Symposium Organizers
Takafumi Fukushima, Tohoku University
Kanchan Ghosal, X-celeprint Inc.
Gregory Whiting, University of Colorado Boulder
Hongbin Yu, Arizona State University
PM04.01: Self-Assembly
Session Chairs
Tuesday PM, November 28, 2017
Sheraton, 3rd Floor, Fairfax A
8:30 AM - *PM04.01.01
Fluidic Microassembly with Surface Tension Effects
Pierre Lambert 1
1 , Université Libre Bruxelles, Brussels Belgium
Show AbstractThis talk relates to fluidic assembly relying on surface tension effects, based on examples developed these last years: capillary gripping [1], capillary self-alignment [2], assembly platform supported by droplets or bubbles [3, 4]. It will be built along three axis.
Firstly, we will present the underlying capillary forces models, emphasizing current research challenges: dynamics of surface tension effects, coupling between the degrees-of-freedom of a liquid meniscus, reliability and repeatability issues due to evaporation, contact angle hysteresis, control of surface tension effects.
Secondly, recent results will be shown on a new approach of thermo-capillary micromanipulation [5,6]. This consists in creating a laser-controlled temperature gradient on a liquid-air interface, leading to a surface tension gradient field which is used to move 500µm components along trajectories located at the interface. This technique is considered to be complementary to capillary self-assembly patterns (Cheerios effect), since it can move individual components. Similar to but unlike natural or Marangoni convection, this technique does not rely on any thermodynamic instability (ie. neither Rayleigh nor Marangoni numbers thresholds are required). Moving particles can be triggered with a 37mW laser power, leading to a temperature difference smaller than 5°C degrees while leading to velocities up to 5 mm/s. The current results include the open loop proof of concept, the experimental characterization of the particle velocity as a function of the laser-particle distance, which is then used to closed-loop control the particle trajectory until a target location. These results are supported by simulation results (Comsol, solving the coupled thermal and flow physics). Recent development on use of light patterns as well as control of particles against a perturbation induced by a neighboring particle.
Finally, the Belgian network MicroMAST - Microfluidics and Micromanipulation: Multiscale Applications of Surface Tension - will be presented. This network is funded by the Belgian Research Agency and has organized the 1st International Conference on Multiscale Applications of Surface Tension last September in Brussels (www.micromast2016.be).
9:00 AM - *PM04.01.02
Interfacial Engineering in MEMS—Moving and Assembling Chips and Drops
Karl Böhringer 1
1 NanoES Institute, University of Washington, Seattle, Washington, United States
Show AbstractA well-known outcome of down-scaling into micrometer dimensions is the dominance of surface over bulk phenomena. Thus, when designing micro-scale systems, the ability to understand and modify surface properties is of utmost importance. A key concept is the "programmable surface" - an interface whose properties can be controlled with high spatial and temporal resolution. This presentation introduces several kinds of engineered programmable surfaces and shows their application in self-assembling microsystems, protein and cell chips, and droplet-based microfluidic systems.
9:30 AM - PM04.01.03
Electric-Field Assisted Self-Assembly of Polystyrene Microspheres for Facile Fabrication of SiO2 Invers Opals
Shih-Cheng Chou 1 , Chen-Hong Liao 1 , Pei-Sung Hung 1 , Yu-Szu Chou 1 , PuWei Wu 1
1 , National Chiao Tung University, Hsinchu Taiwan
Show AbstractIn this work, we demonstrate a scheme utilizing both direct-current and alternative current electric fields as driving forces for rapid assembly of polystyrene microspheres and better infiltration of silica sol particles. Essentially, this method employs both electrophoresis and dielectrophoresis sequentially to construct colloidal crystals with interstitial voids filled with silica. Electrophoresis involves a direct current electric field which directs the movement of suspended microspheres for closely-packed self-assembly, known as colloidal crystals, on selective substrates. Dielectrophoresis entails an alternative current electric field which guides the silica sols in enhanced permeation throughout the colloidal template. Various experimental variables for both electrophoresis and dielectrophoresis are explored and the resulting effects are discussed.
9:45 AM - PM04.01.04
Remotely Controlled Three-Dimensional Self-Assembly Using Time-Varying Magnetic Field for Biomedical Applications
Chao Liu 1 , Jeong-Hyun Cho 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show AbstractA novel self-assembly technique has been developed to remotely trigger the assembly of a micro-scale structure using a high frequency induction energy. Metal thin films are embedded in the micro-scale structures, which generate heat energy due to eddy current and Ohmic heating under time-varying magnetic field controlled by a remotely located induction energy source. The generated heat energy melts polymeric hinges (polycaprolactone, PCL) and generates surface tension force to lift up the panels between hinges. This transforms the two-dimensional (2D) nets into three-dimensional (3D) structures. The self-assembly process can be precisely controlled by tuning the geometrical parameters (e.g., thickness, area) of the metal films as well as the conditions (e.g., power, frequency) of the induction energy source, highly enhancing the manipulative capability of the self-assembly process. Since the PCL hinge material has a low melting point (around 60 oC), the self-assembly can be trigger at a low temperature, limiting the harm of heat energy to living tissues and organs during the assembly process. In addition, since the energy source (magnetic field) triggering the self-assembly is biocompatible, the remotely controlled self-assembly using induction energy is ideal for biomedical applications like 3D biosensing, cell encapsulation and drug delivery.
PM04.02: Interconnect
Session Chairs
Tuesday PM, November 28, 2017
Sheraton, 3rd Floor, Fairfax A
10:30 AM - *PM04.02.01
Self-Align and Self-Assembly at the Nanometer and Milimeter Scale—Modeling and Cases of Use
Lea DiCioccio 1 , Jean Berthier 1 , Yézouma D. Zonou 1 , David Peyrade 2 , Amandine Jouve 1 , Olivier Castany 1
1 , CEA, LETI, Grenoble France, 2 LTM, Centre National de la Recherche Scientifique (CNRS), Grenoble France
Show AbstractNanoparticles, plates, fibers, can self-align using capillarity. This property has been demonstrated for nanoparticles, microelectronic chips and optical components of dimensions comprised between 20 nm, 500 μm and a few millimeters. Capillary self-assembly relies on the restoring forces and torques exerced by the surface tension of the free surfaces of a droplet switched between the two plates or fibers. These forces and torques are associated to the minimization of the surface energy of the liquid. Extensive applications can be found for sensors, actuators and electronic circuitry and lab-on-a-chip systems. Furthermore self-assembly is a parallel technique and can be used for device sizes ranging from millimeters to nanometers for which pick and place serial process, accurate and reliable at the millimeter scale, is not the preferred one at the nanoscale due to sticking problems, fragility and large number of components. The self -align can coupled to assembly technique, such as direct bonding or micro bump fusion, in order to align and bond in one operation. In this paper, for different sizes of object, results will be shown and discussed. Modelling for the align phenomenon will be presented especially for the die to wafer approach.
11:00 AM - PM04.02.02
Interfacial Self-Assembly in Dual-Droplet Inkjet Printing
Karam Al-Milaji 1 , Tse Nga Ng 2 , Hong Zhao 1
1 Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia, United States, 2 Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California, United States
Show AbstractThe well-known coffee ring effect causes colloidal particles convectively transport towards the contact line due to faster evaporation at the edge of the colloidal droplet. In this study, we demonstrated self-assembly of colloidal particles in a dual-droplet inkjet printing configuration to suppress coffee ring effect and to produce nearly monolayer deposition of the colloidal particles. Acting as a Langmuir-Blodgett trough, a supporting droplet is deposited on the substrate followed by a second droplet (i.e., wetting droplet) which contains polystyrene (PS) colloidal particles. In favorable conditions, the wetting droplet quickly spreads over the supporting droplet upon impact, due to its low surface tension. In this study, deionized water is used as the solvent for supporting droplets; a mixture of ethanol/water as the solvent for wetting droplets. The effects of solvent composition of wetting droplets, functionalization and concentration of PS particles on the final deposition morphology were investigated. When the conditions facilitate a network formation among the colloidal particles on the water-air interface during the evaporation of supporting droplet, nearly monolayer deposition of the PS particles is obtained. The colloidal particles experience dominantly particle-particle and particle-interface interactions instead of particle-substrate interactions. A higher particle concentration leads to multilayer or buckling of the deposition film and a lower particle concentration results in a monolayer deposition with an incomplete coverage of the entire droplet footprint. The underlying self-assembly mechanism is insensitive to substrates and can be applied to many other material/substrate combinations. This dual-droplet inkjet printing process has a significant implication in fabricating optical and electrical functional devices where close packing and alignment of the materials are highly desirable.
11:15 AM - PM04.02.03
Rapid and Non-Destructive Nano-Micro Optical Patterning System for Conjugated Polymers
Adam Moule 1 , Ian Jacobs 1 , Jun Li 1 , Zaira Bedolla Valdez 1
1 , University of California, Davis, Davis, California, United States
Show AbstractA significant obstacle for the industrial development of organic electronic devices is the lack of a patterning technology having the disruptive power that photolithography exerted in traditional microelectronics. Here we present a new scalable patterning technology for organic semiconductors called dopant-induced solubility control (DISC) that takes advantage of the existing photolithography infrastructure and is compatible with digital direct-write patterning and sequential roll-to-roll (R2R) solution coating. The solubility of semiconducting polymers can be “switched off” using addition of a high electron affinity molecular dopant. Spontaneous charge transfer with the dopant generates an organic salt that is completely insoluble in non-polar solutions. Here we demonstrate both chemical and optical mechanisms by which the doping can be reversed and the solubility of the polymer is “switched back on.” Using these techniques, we are able to vertically stack and laterally pattern mutually soluble polymer layers, which are vital processing steps needed to expand the use of organic semiconductors in device applications. Optimization of these techniques has yielded diffraction limited film patterning with regular features of 200-300 nm with only solution processing steps and direct write laser patterning. Comparison of patterned and initial samples shows no change in the optical, electrical or chemical properties of the polymer. DISC patterning offers a new avenue to process semiconducting polymers with applications in all areas of organic electronics.
11:30 AM - PM04.02.04
Nanoprinting of Metallic Conductive Inks with Fountain Pen Nanolithography
Talia Yeshua 1 4 , Michael Layani 3 5 , Rimma Dechter 1 , Uwe Huebner 2 , Shlomo Magdassi 3 , Aaron Lewis 1
1 Applied Physics, The Hebrew University of Jerusalem, Jerusalem Israel, 4 Applied Physics, Lev Academic Center, Jerusalem Israel, 3 Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem Israel, 5 School of Materials Science and Engineering, Nanyang Technological University, Nanyang Singapore, 2 , Leibniz Institute of Photonics Technology, Jena Germany
Show AbstractThe field of printed electronics is trying to reduce the dimensions of the electrical components continually. Here we show the printing of conductive metallic lines having widths as small as 15 nm and can be controlled up to a few µm by using Fountain Pen Nanolithography (FPN). Such varying dimensions of conductive lines, with the ability to flexibly print on various complex substrates at selected locations and with a variety of inks, does not currently exist. The FPN technique is based on a force sensing bent nanopipette and the printing with force feedback is similar to a pen in the nano regime. The geometry of the nanopen and atomic force microscopy system used allows for the placement of the printing tip with the highest of optical resolutions. Thus, any desired location can be rapidly accessed with sub-micrometer precision. Using this nanopen, investigations of various inks were undertaken together with instrumental and script-tool development. This has led to the printing of conductive lines using inks composed of silver nanoparticles and salt solutions of silver and copper. In addition, it is shown that printing over structures with varying heights and material characteristics is achievable without changing the dimension of the line. The line widths are varied by using nanopens with different orifices or by tailoring the wetting properties of the ink on the substrate. Metallic interconnections of conducting lines are reported with a conductivity of up to 0.45% of bulk silver. The results demonstrate both conductive lines and electrical interconnections that can be printed at scales presently not being addressed.
11:45 AM - PM04.02.05
Micro-Coaxial Interconnect Strategies for Rapid System-in-Package Integration
Peter Lewis 1 , M Meinhold 1 , Daniela Torres 2 1 , M Miller 1 , Sara Barron 1 , Anthony Kopa 1 , Caprice Gray 1
1 , Draper Laboratory, Cambridge, Massachusetts, United States, 2 , Tufts University, Medford, Massachusetts, United States
Show AbstractWe have conceived a new microelectronics packaging platform in which interconnects among commercial off-the-shelf (COTS) components are made with custom fabricated micro-coaxial wires (micro-coax). This method can be applied to package-scale components as well as die scale. By implementing this paradigm, the circuit designers are freed from the constraints of standard packaging design rules, greatly reducing integration and circuit design re-spin time.
In place of the standard micro-assembly and packaging, this platform requires only that components be placed on one side of a double-sided interposer with through vias. The micro-coax are attached to the other side of the board. The micro-coaxial wires themselves are fabricated in-house or at custom vendors, with a metal core (Cu, 25 to 125 micrometer diameter), dielectric layer (polyurethane or polyimide, 1 to 10 micrometer thickness), and metal shield (Au, Ag, or Cu, 3 to 30 micrometer thickness) and are designed for transmitting power to the microchips. These power distribution micro-coax have minimal impedance with the majority of the cross section as metal. (In a later phase, micro-coax for transmitting signals between micro-chips will be designed and fabricated to have impedance between 30-75 ohms depending on the chip requirements.) In this presentation, we will focus on joining strategies for low impedance micro-coaxial wires for power distribution. The joining strategy must introduce minimal additional impedance and must be compatible with automation because complex microelectronic systems typically have high I/O count and therefore require hundreds or thousands of joints between the micro-coax and the interposer.
We have connected micro-coax intended for power distribution (50 micron core diameter, 2 microns of polyurethane, 10 microns of Au) to a high frequency test fixtures using several different joining processes. The test fixture data is used to calculate the inductance, resistance and capacitance (components of impedance) of the wires and joining points. Inductance dominate the impedance for our power coax at high frequencies. Core bonding techniques include thermo-sonic bonding and soldering. The micro-coax shield is connected with one of the following methods: (1)a short jumper wire bond from shield to pad, (2) by a ink jet printing insulating epoxy over the signal connection, then printing conductive epoxy to the ground, (3) aerosol jet printing an insulation layer over the core connection, then print a Ag ink layer from shield to pad. The inductance of these connections range from 10 pH to 120 pH. For comparison, the inductance of our micro-coax is 20 pH/mm. These results align well with our joint simulations, which indicate the importance of minimizing the physical volume of the joint. To date, the aerosol jet printed shield to ground connection strategy is the most promising for both automation and minimizing joint volume.
PM04.03: Optical Assembly
Session Chairs
Tuesday PM, November 28, 2017
Sheraton, 3rd Floor, Fairfax A
1:30 PM - *PM04.03.01
Origami Silicon Optoelectronics for Hemispherical Electronic Eye Systems
Yei Hwan Jung 1 , Kan Zhang 1 , Solomon Mikael 1 , Shaoqin Gong 2 , Weidong Zhou 3 , Zhenqiang Ma 1
1 Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States, 2 Biomedical Engineering and Wisconsin Institute for Discovery, University of Wisconsin–Madison, Madison, Wisconsin, United States, 3 Electrical Engineering, The University of Texas at Arlington, Arlington, Texas, United States
Show AbstractInspired by the marvelous visual systems in biology, recent efforts toward evolving camera systems have focused on transforming planar image sensor array into hemispherical formats. Digital image sensors in hemispherical geometries offer unique imaging advantages over their planar counterparts, such as wide field of view and low aberrations. The hemispherical geometry not only eliminates complex optical elements for refined imaging, but also adds new features such as panoramic view and infinite depth of field. Numerous successful designs that incorporate state-of-the-art materials brought such unusual format sensors a step closer to practical cameras. Nevertheless, the challenge is to establish commercial infrastructure for such technically advanced manufacturing processes. Increasing the pixel density for high spatial resolution is another challenge. Here, a simple origami approach for fabricating single-crystalline silicon-based focal plane array and artificial compound eye that have near flawless hemispherical structures is presented. Convex isogonal polyhedral concepts allow certain combinations of polygons to fold into spherical formats. Using each polygon block as a sensor pixel, the devices were shaped into maps of truncated icosahedron and fabricated on flexible sheets utilizing conventional silicon manufacturing processes and further folded into either a concave hemisphere for focal plane array or a convex structure for artificial compound eye. These two prototypes in concave and convex shapes represent simple and low-cost methods as well as flexible optimization parameters in terms of pixel density and hemisphere design for electronic eye systems. Results and simulations demonstrated in this work combined with miniature size and simplicity of the design establish practical technology for integration with conventional electronic devices. Applying this concept to state-of-the-art digital cameras that capture high quality images or surveillance cameras using infrared night vision are also desirable which would further expand the capabilities of cameras.
2:00 PM - PM04.03.02
Controlled Assembly of Nanoparticles into 3D Microstructures
Shanying Cui 1 , Adam Gross 1 , Christopher Roper 1 , John Vajo 1
1 , HRL Laboratories, Malibu, California, United States
Show AbstractWe describe a new charge titration assembly process that enables the organization of nano-sized particles into sub-mm, multilayered high density arrays without organic structure directing agents. This fast, scalable, and material-agnostic assembly process will enable leveraging nanoscale properties in macroscale components for magnetic and optical applications.
Assembly through charge titration is applied to multiple particle compositions and shapes. The particles are first synthesized and their surface charges versus pH are measured with a zeta-potential analyzer. Next, we suspend the particles in an aqueous solution and finely control the interparticle forces by tuning the pH gradually and uniformly throughout the solution towards the particles’ isoelectric point (IEP) where interparticle attraction results in assembled arrays of nanoparticles. We find that the rate of pH change, especially near the IEP, plays an important role in the assembly size and quality. This is in contrast to normal titration methods that result in localized changes in pH and uncontrolled agglomeration of nanoparticles. Using this method, 100 micron sized aligned and close-packed arrays from 100 nm particles are assembled. We demonstrate such assembly with iron oxide hydroxide (FeOOH) nanorods, lithium yttrium fluoride (LiYF4) nanoprisms, and sodium yttrium fluoride (NaYF4) nanohexagons, showing the material and shape versatility of this approach. This technique can be extended to create large-scale core-shell structures consisting of a core assembled material surrounded by a second material. Our assembled structures have applicability to magnetic and infrared scattering materials.
2:15 PM - PM04.03.03
Direct Transfer Printing for Assembly of Flexible Hybrid Electronics and Photonics Devices
David Grierson 1 , Frank Flack 2 , Max Lagally 2 , Kevin Turner 1 3
1 , systeMECH, Inc, Madison, Wisconsin, United States, 2 Department of Materials Science and Engineering, University of Wisconsin–Madison, Madison, Wisconsin, United States, 3 Mechanical Engineering and Applied Mechanics , University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractA direct transfer-printing approach that enables deterministic assembly of thin, high-performance semiconductor die and layers directly onto flexible and soft substrates is presented. Transfer-printing experiments show that direct transfer printing can achieve high-yield and high-fidelity transfer of thin silicon components (100 nm – 10 μm thickness) with diverse architectures and a wide range of lateral dimensions (nm – cm) to flexible polyethylene terephthalate substrates over chip-scale areas. The underlying contact mechanics of direct transfer printing are investigated through finite element simulations of the transfer process. The mechanics models are shown to provide guidance for controlling the contact area, contact stress, and strain in the flexible substrate during component transfer, all of which are critical for achieving reproducible and high-yield printing. Implementation of direct transfer printing for the manufacture of flexible hybrid electronics (FHE) and photonics will be discussed.
2:30 PM - PM04.03.04
Self-Assembled THz Octagrams as 3D Isotropic Metamaterials
Kriti Agarwal 1 , Chao Liu 1 , Jeong-Hyun Cho 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show Abstract
Split-ring resonator (SRR) based metamaterials have been studied for the development of a diverse range of sensors for the detection of dielectric constant, displacement, and targeted particle due to the high dependence of their frequency response on the resonator dimensions as well as the permittivity within the split. However, the angle dependence of these two-dimensional (2D) structures presents a major hurdle due to the switching of the resonance between electric (1st mode) and magnetic (2nd mode) resonances as well as no resonance when the incident electric field is perpendicular to the SRR plane. The angle dependence renders SRR sensors unusable for detection of targeted molecules in cases when the orientation of the SRR is difficult to control. The 2D nature of the existing planar SRR structures does not allow to overcome this limitation. However, when self-assembled into three-dimensional (3D) structures previously unrealized optical responses can be achieved that extend the capabilities of the SRRs. A perfectly isotropic frequency response (angle independent) is obtained by transformation of the conventional C-shaped SRR structure into a symmetric X-shaped segments such that the split within the SRR is no longer 2D but rather it is 3D occurring at the corners of cube. The 3D split is equally moderated by the three vectors (electric field, magnetic field, and wave) at all orientations of the resonator forming an 8-pointed star-shaped octagram split-ring resonator (OSRR) demonstrating a perfectly isotropic response with no changes in resonant frequency or amplitude for any orientation. The isotropic 3D OSRR allows the in-vivo detection of target molecules with a 25 times higher sensitivity than the corresponding 2D structure due to the strong coupling between OSRR segments producing a domino effect that enhances small changes in local permittivity. At the same time, the 3D OSRR achieves a two-fold advantage by allowing the monitoring of the isotropic transmission amplitude for minute changes in an analyte as well as the monitoring of the resonant frequency for large changes in analytes.
2:45 PM - PM04.03.05
Transfer Printing GaN from SiC Substrates
Shawn Mack 1 , Laura Ruppalt 1 , Brian Downey 1 , D. Scott Katzer 1 , James Champlain 1 , David Meyer 1
1 Electronics Science and Technology Division, U.S. Naval Research Laboratory, Washington, District of Columbia, United States
Show AbstractEpitaxial III-N heterostructures grown directly on SiC have state-of-the-art properties but lack selective etch chemistries accessible with alternative substrates. Transition metal-nitride (β-Nb2N) layers on SiC serve as equivalent epitaxial templates for III-N heterostructures and etch with very high selectivity, opening a new route towards GaN epitaxial lift-off. We demonstrate elastomer-based transfer printing of GaN HEMT heterostructures and processed devices from SiC substrates with β-Nb2N sacrificial layers. Electrical properties are commensurate with native substrate performance and vary with the thermal conductivity of heterogeneous substrates. Strategies to minimize stress gradients and achieve planar bonding will be discussed.
PM04.04: 3D Printing
Session Chairs
Tuesday PM, November 28, 2017
Sheraton, 3rd Floor, Fairfax A
3:30 PM - PM04.04.01
A 3D-Printed-Layered Module of Compliant Electrostatic Gripper Consisting of Elastically Deformable Bipolar Micro-Probes
Kazuki Wakabayashi 1 , Kento Kawano 1 , Kunio Takahashi 1 , Shigeki Saito 1
1 , Tokyo Institute of Technology, Tokyo Japan
Show AbstractIn this study, we propose a new concept of compliant electrostatic gripper by stacking 3D-printed-layered modules that consist of elastically-deformable bipolar micro-probes. Due to the module structure, the micro-probes tips can be aligned precisely on the large surface area where the electrostatic force is generated by the bipolar electrodes. The proposed gripper is expected to work effectively on thin and/or fragile objects with compliance on the surface without any damage due to excessive stress. The module is prototyped by 3D printer, and the performance as a holding gripper is experimentally evaluated.
To date, new handling techniques of thin and/or fragile sheet materials such as polymer films, papers, and fabrics have been required in order to develop advanced wearable devices, and many other applications, although the conventional electrostatic chucks work successfully typically for flat and hard wafer in the semi-conductor fabrication. In recent years, our research group has developed compliant bipolar electrostatic grippers, and then investigated how the grippers work in the past studies. Still the critical issue remains to be solved that the effective area for electrostatic force, which is defined by the array of micro-probe tips, should be enlarged while the spatial density of bipolar electrodes should be increased. In addition, it is currently well-recognized that insulation between the bipolar electrodes is seriously important to avoid the damage from the breakdown in case of spatially high density of electrodes. To solve this issue by layer-by-layer fabrication, 3D printing technology can be considered one of the most useful for applications in relatively large scale.
The module having bipolar probes consists of three-sublayer (conductor-insulator-conductor) structure. The 80mm-long bipolar probes are arranged at 45-degrees to interface. The dimensions of a rectangle tip surface of the bipolar probes are 1.2mm in width and 1.6mm in height. Conductive and insulating layers are 0.4mm and 0.8mm in thickness, respectively. The bipolar probes are fabricated by a fused deposition modeling (FDM) 3D printer having a 0.4mm-diameter nozzle. Carbon-mixed and ABS filaments are used for conductor and insulator, respectively.
In experiment, the force curve is determined, and is partially compared with a finite element analysis to evaluate the compliance, the maximum force, and other characteristics. Additionally the force per unit effective area, which includes the gap between the probes, is calculated to discuss the future design that can enables the potentially maximum performance for real application. Subsequently, demonstrations of pick-up experiments for a PP film, a printing paper and a fabric are conducted to show that even the prototyped module work as handling device for thin sheet materials under particular conditions, and thus the proposed concept will highly contribute to the fabrication technology in the next generation.
3:45 PM - PM04.04.02
Multiplexed Multi-Material 3D Printing
Mark Skylar-Scott 1 , Jochen Mueller 2 , Claas Visser 3 , Jennifer Lewis 1
1 Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts, United States, 2 , ETH Zürich, Zurich Switzerland, 3 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States
Show AbstractWe report a multiplexed, multi-material 3D printing system (MM3D) that enables local composition and architecture to be precisely controlled. Specifically, we developed multi-nozzle printheads for direct ink writing that consist of bifurcating, microfluidic-based nozzle arrays. Each nozzle allows up to four different materials to be seamlessly switched on demand during the printing process. To demonstrate our MM3D platform, we printed elastomeric inks with programmable stiffness as well as highly reactive inks in complex 3D architectures.
4:00 PM - PM04.04.03
Versatile Method for Precise Metallic Pattering of Soft, Micro-Structured 3D Structures
Jeremy Reeves 1 , Rachael Jayne 1 , Thomas Stark 1 , Lawrence Barrett 1 , Richard Lally 1 , Alice White 1 , David Bishop 1
1 , Boston University, Boston, Massachusetts, United States
Show AbstractWe present methods for the fabrication of mechanical metamaterial scaffolds with engineered optical and mechanical properties. A MEMS-based stencil-lithography technique allows for the application of metallic patterns to soft direct-laser-written polymer scaffolds with micron-scale alignment to the mechanical metamaterial substrate. This allows for the printing of nanoscale patterns on 3D structures with nontrivial topography and on materials that are incompatible with traditional lithographic techniques. A mechanically-tunable optical metamaterial, operating in the mid-infrared, is demonstrated to highlight the versatility and precision of the fabrication technique. Further applications, enabled by the integration of these structures with MEMS actuators, are also discussed.
4:15 PM - PM04.04.04
Demonstration of Direct-Metal 3D Printing via Local Electrochemical Deposition
Marco Stefancich 2 , Matteo Chiesa 1 , Harry Apostoleris 1 , Sverre Minnesjord 3
2 , Dubai Electricity and Water Authority, Dubai United Arab Emirates, 1 , Khalifa University of Science and Technology, Abu Dhabi United Arab Emirates, 3 , Fluid Metal 3D, Skien Norway
Show Abstract3D printing of metal is a widely sought after technique for the manufacturer’s toolbox, but at present the technique is limited to large and expensive laser or energy-based sintering systems. We have demonstrated the direct printing of pure metal at room temperature via localized, jet-assisted electrodeposition in a compact system that could dramatically improve over current metal-printer costs. We describe the operation of the system and demonstrate the printing of mm and cm-scale 3D structures in copper with deposition rates up to 16 um/s. We further consider optimizations of the system to broaden its applicability.
4:30 PM - PM04.04.05
3D Printing of Heterogeneous Composite RF Devices
Bradley Duncan 1 , Maxwell Plaut 1 , Benjamin Barclay 1 , Sebastien Uzel 2 , Andrew Zai 3 1 , Michael Lis 4 1 , David Cipolle 1 , John Russo 1 , Jennifer Lewis 2 , Theodore Fedynyshyn 1
1 , Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts, United States, 2 , Harvard University, Cambridge, Massachusetts, United States, 3 , Humatics Corporation, Cambridge, Massachusetts, United States, 4 , Viridis 3D LLC, Lowell, Massachusetts, United States
Show AbstractMillimeter-wave (>30 GHz) communication devices, such as 5G phones, permit higher bandwidth and offer size, weight, and power (SWaP) advantages over lower frequency systems. Dielectric materials used for millimeter-wave applications must possess low-loss characteristics and sub-mm feature resolution. 3D printing offers a viable strategy for the development and production of radio frequency (RF) devices structures. However, most 3D printable materials demonstrate low dielectric constants and/or high losses at these higher frequencies limiting their potential SWaP benefits. To date, there has been limited success in controlling both the geometric and compositional deposition of materials for millimeter-wave RF devices. Here, we describe a 3D printing strategy based on both sequential and gradient deposition of composite inks to generate novel RF devices. The hybrid inks comprised of block copolymers and surface modified ceramic nanoparticles demonstrate low-losses and high dielectric constants at millimeter-wave frequencies. The dielectric constant of the final printed structure can be programmably controlled by varying the polymer-to-nanoparticle ratio within the ink on-the-fly using an active mixing nozzle. Using this approach, we will create gradient dielectrics and characterize their performance compared to predictions from theoretical modeling.
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This material is based upon work supported by the Assistant Secretary of Defense for Research and Engineering under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily represent the views of the Department of Homeland Security.
4:45 PM - PM04.04.06
Reconfigurable, High-Resolution Three-Dimensional Printing of Liquid Metal Alloy with Stable Electrical Contact
Young-Geun Park 1 , Subin Jo 1 , Byeong Wan An 1 , Jang-Ung Park 1
1 , UNIST, Ulsan Korea (the Republic of)
Show AbstractThe stretchability of interconnect is essential for stretchable electronic devices because it occupies a large area portion of electronic devices and circuits, consequently absorbing most of the strains when stretched. In this reason, various kinds of stretchable interconnect and electrodes have been developed. Printing techniques for interconnection can minimize damage to the substrate and devices and also have high compatibility for forming three-dimensional (3D) structure. Liquid metal has excellent mechanical and electrical properties in that it has a conductivity of metals and almost infinite stretchability.
New printing technology using liquid metal is developed, named “Stop-and-go printing”. According to this printing method, the printed patterns on the substrate can be picked up and precisely reconfigured into the desired new two-dimensional (2D) structure or even 3D freestanding structure. Also, to the best of our knowledge, liquid metal is printed in the highest resolution (~ 8 μm linewidth) than ever reported, with enabling precise control of start and finish point, on the rigid and soft substrate. Liquid metal penetration into solid metals has been the bottleneck of liquid metal usability. Through the stop-and-go printing, the liquid metal alloy has modified compatibility with solid metals in that the printing method forms thin oxide skin on entire liquid metal surfaces thus this printing method set liquid metal as a reliable stretchable interconnects. We demonstrated the reconfigurable printing method into certain applications: to stack the EGaIn in z-axis without electrical contact, to switch light-emitting diode (LED) pixels, to tune the resonance frequency of spiral coil antenna, to form the flexible and stretchable interconnect for the micro-LED array. 2D and 3D structured stop-and-go printed liquid metals are able to be encapsulated with soft polymers such as polydimethylsiloxane thus the liquid metal interconnect can be protected from external impact and guarantees sustainability. The properties as interconnect, such as electrical properties (maximum current density ~ 1010 A/m2) and thermal properties (3D structure stability at ~ 500°C) are tested.
Symposium Organizers
Takafumi Fukushima, Tohoku University
Kanchan Ghosal, X-celeprint Inc.
Gregory Whiting, University of Colorado Boulder
Hongbin Yu, Arizona State University
PM04.05: Transfer Printing
Session Chairs
Wednesday AM, November 29, 2017
Sheraton, 3rd Floor, Fairfax A
8:30 AM - *PM04.05.01
Transfer Printing for LEGO-Like Microassembly and Nanomaterial Integration
Seok Kim 1
1 , University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show AbstractReversible dry adhesion-based transfer printing provides a highly straightforward pathway to heterogeneous material integration. The speaker presents his recent research outcomes accomplished in his laboratory which has been exploring responsive surfaces, microassembly, and nanomanufacturing technologies. The first part introduces an engineered reversible dry adhesive made of a shape memory polymer and highlights its consumer product-like prototype. The second part shows how his reversible dry adhesive advances transfer printing techniques to enable his microassemly called micro-LEGO and summarizes the applications of micro-LEGO with the examples not only of 3D heterogeneous micro-structures but also of devices such as a microtoroid resonator, a tip-tilt-piston micromirror, and a RF MEMS switch. Finally, the third part demonstrates his transfer printing techniques which are further exploited in order to pattern and integrate colloidal quantum dot films. The strategies presented in his talk benefit research activities in smart dry adhesives, 3D MEMS, and nano devices.
9:00 AM - *PM04.05.02
Mechanics of Transfer-Printing Ultrathin Nanomembranes Including 2D Materials
Nanshu Lu 1
1 , The University of Texas at Austin, Austin, Texas, United States
Show AbstractMany high-performance flexible and stretchable electronics are manufactured by a so-called transferring-printing process, which involves picking up a high-quality inorganic nanomembrane (NM) from its donor substrate and delivering it to a foreign substrate via elastomeric stamps. As NM thickness reduces to nanometers or subnanometers (e.g., 2D materials), it can easily rupture during the picking up or printing process and form blisters after printing, which fail the transfer-printing. An important factor that controls the transfer-printing quality is the adhesion of various interfaces. We have therefore experimentally measured the adhesion energy between elastomer and NMs, between NMs and silicon wafer, as well as between different NMs (e.g. 2D heterostructures) using a buckling/blistering metrology. We can then predict the tensile stress in the nanomembrane induced by stamp compression during both picking up and printing processes. While the tensile stress in the NM increases monotonically with the compressive load applied on the stamp, an abrupt increase of the tensile stress can occur when NM-substrate interface starts to fail. An intrinsic length scale, factoring together interface adhesion, stamp properties and geometry, is identified for determining the appropriate compressive load on the stamp, which should be large enough to engage stamp-NM contact but not too large to rupture the NM. Recommendations for stamp material and size will also be offered.
9:30 AM - PM04.05.03
Soft Composite Nanofoams with Electrically Switchable Adhesion for Micro Transfer Printing
Sanha Kim 1 , Yijie Jiang 2 , Chunxu Chen 2 , Hangbo Zhao 1 , Christine Jacob 1 , Kevin Turner 2 , A. John Hart 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 , University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractIntegration of high-performance microscale materials and nanofabricated devices onto target objects realizing new kinds of heterogeneous systems requires advanced pick-and-place techniques. At present, elastomers, which have adhesion that can be controlled via peeling speed, are the most widely utilized stamp materials. However, transfer techniques based on viscoelastic stamp materials have limitations, including low on-off adhesion ratios, time-dependent adhesive strength, and sensitivity to ambient (e.g., high temperature, pressure, humidity).
Here, we introduce engineered composite nanofoams with electrically switchable adhesion, as a new stamp surface for precision microtransfer printing. The nanofoams are composed of carbon nanotube (CNT) forests (vertically aligned, ~10 nm diameter CNTs in the form of films or structured arrays) directly grown on conductive bottom electrodes and conformally coated with an ultrathin (<1 nm) layer of alumina. As CNT forests are highly porous (>90 vol%), the surface is mechanically soft and compliant (compressive modulus of ~10-200 MPa and hardness of ~5-30 MPa), which enables good mechanical contact against a broad range of micro objects with minimal van der Waals adhesion. The adhesion between the nanofoam stamp and target objects can be effectively tuned by inducing a stronger electrostatic attraction through the application of an external voltage applied to the bottom electrodes. We find that the adhesive force scales with the square of the applied voltage and can be increased up to 100-fold over the initial van der Waals adhesion at an applied voltage of 30 V. The experiments are supported by electromechanical contact models that elucidate the key design parameters. Finally, we demonstrate voltage-controlled pick-and-place of microparticles and unpackaged micro-LEDs.
9:45 AM - PM04.05.04
High Fidelity Transfer Printing of Compliant Polymer Thin Films Using Pre-Strained Stamps and Application in Organic Electronic Device Fabrication
Pratik Sen 1 , Michael Kudenov 1 , Brendan O'Connor 1
1 , North Carolina State Univ, Raleigh, North Carolina, United States
Show AbstractTransfer printing is a useful technique that allows for the deterministic assembly of stacked micro/nano materials in electronic devices. Transfer printing using specific mechanical loading protocols has been shown to be highly successful in printing rigid solid inks such as silicon. These loading protocols include the application of a shear load to the stamp, the use of pressure, and varying the delamination kinetics during the process. In this presentation, we report a novel transfer printing method exploiting a unique mechanical loading process titled STrain Assisted soft-Matter Printing (STAMP) that is highly effective in printing compliant polymer thin films. This method utilizes the release of pre-strain on an elastomer stamp to facilitate high fidelity printing of polymers that has minimal impact on the polymer film or receiving surface.
The STAMP method is particularly important for polymer-based electronics where multilayer polymer films are often necessary, but are challenging to fabricate due to solution casting methods that may dissolve underlying layers or suffer from dewetting. To overcome these challenges numerous transfer printing methods for organic semiconductors have been developed, however they often rely on external heating, surface treatments, the use of sacrificial layers or immersion in a liquid, which can be detrimental to the final device. The STAMP method described is free of these manipulations resulting in sharp heterogeneous interfaces with no impact of the film morphology during the printing process. We will describe the mechanics behind the STAMP technique and show that this approach can overcome a large unfavorable difference in the thermodynamic work of adhesion between the stamp/ink and ink/receiver interfaces. The limits of the method will be probed through an analysis of transfer printing PEDOT:PSS films with varying adhesion characteristics tuned through the use of additives. The printing methods will then be used to demonstrate successful fabrication of a number of organic electronic devices. A particular focus will be on printing polymer semiconductor active layers and PEDOT:PSS electrodes to realize high performance semitransparent organic photodetectors.
PM04.06: Elastomer Assembly
Session Chairs
Wednesday PM, November 29, 2017
Sheraton, 3rd Floor, Fairfax A
10:30 AM - *PM04.06.01
Transfer-Printed Microscale Semiconductors—Techniques and Applications
Christopher Bower 1
1 , X-Celeprint Inc., Dyke Parade Ireland
Show AbstractIntegrating ultra-miniaturized compound semiconductor devices onto non-native substrates enables new kinds of products with desirable functionalities and cost structures that are inaccessible by conventional means. Micro assembly technologies are the practical ways to make such micro-scale combinations possible. Micro transfer printing technology (µTP) is a widely-demonstrated form of micro assembly, having demonstrated applicability in optical communications, magnetic storage, photovoltaics, bio-integrated electronics, and displays. The common value proposition of µTP in all of these applications is to provide a product that uses the most advantageous semiconductor devices and has the most desirable form factor. Those characteristics provide cost benefits, performance metrics, or combinations of properties that are inaccessible or impractical without µTP.
11:00 AM - PM04.06.02
Bifurcation of Self-Folded Planar Bilayers—Mechanistic Understandings and Application to Realize Functional Shapes in a Programmable Manner
Arif Abdullah 2 , Jimmy Hsia 1
2 Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois, United States, 1 Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
Show AbstractStimuli-responsive curving of thin shells, also known as self-folding, is a topic of substantial technological importance due to its potential to overcome the limitations of traditional planar lithographic techniques and actuate minuscule architectures. Owing to their thin configurations, the shape transformation behaviors of self-folding structures are often governed by structural instabilities. Our research investigates the effects of one such instability mode, namely bifurcation buckling, on the stimuli-responsive shape transformation behaviors of planar two-dimensional bilayers.
In the first part of this work, we intended to understand the bifurcation phenomenon by considering a set of regular convex bilayer polygons morphing under biaxial mismatch strains (one layer expands isotropically with respect to the other). We developed finite element models to elucidate the effects of original shape, geometric nonlinearities, and edge layers on the morphing behavior (pre- and post-bifurcation) of bilayers. Our calculations revealed that for all the geometries, the bilayers formed axisymmetric shallow spherical caps at lower strains but bifurcated into asymmetric cylindrical shapes beyond some critical value of the mismatch strain. To verify the computational predictions, we fabricated bilayer PDMS (Polydimethylsiloxane) samples with varying cross-linking densities and then performed swelling experiments in organic solvents.
In the second part of this work, we applied our knowledge on bilayer bifurcation to design stimuli-responsive gripper-like architectures capable of tetherless actuation. We considered bilayer regular star polygons (with varying geometric parameters) as they closely resemble the prehensile biological hand seen in primates. For gripping functionalities, the star polygons need to resist bifurcation and maintain their axisymmetric spherical configurations up to very high strains to capture and hold on to desired objects. We developed finite element models to establish the geometry – mismatch strain – curvature relationships of star polygons and identified the key structural parameters necessary to achieve axisymmetric gripper-like configurations. We then verified our model predictions by performing swelling experiments of PDMS bilayers in organic solvents.
Through a combination of finite element modeling and experiments, we developed mechanistic understandings of a structural instability mode and demonstrated its applicability to achieve functional shapes in a programmable manner. Thus, our research contributes to the broad field of self-assembly as the findings could motivate functional devices across multiple disciplines such as sensing, artificial muscles, robotics, therapeutic cargos, and reconfigurable biomedical devices.
11:15 AM - PM04.06.03
Elastomeric Surfaces as 2D “Assemblers”—Micromanipulation, Assembly and Transfer of Functional Polymeric Microstructures Using Silicone Films
T.P. Vinod 1 , Stephen Morin 1
1 , University of Nebraska–Lincoln, Lincoln, Nebraska, United States
Show AbstractThe directed assembly, via physical or chemical driving forces, of microscale components promises to enable functional structures that are not possible via self-assembly alone. Strategies which rely on the “active” micromanipulation of components through reversible mechanical deformations of elastomeric substrates represent exciting new opportunities in directed assembly. We are investigating scalable techniques that use the precise mechanical actuation of elastic substrates to manipulate and assemble large numbers of microscale building blocks rationally and simultaneously to yield extended structures. Specifically, we report the deposition of polystyrene microparticles of discrete sizes (2 μm to 30 μm) in ordered patterns with single-particle or multi-particle domains onto polydimethylsiloxane substrates using microcontact printing and microparticle screen printing where, by stretching and relaxing the elastomeric support, they are rationally assembled into larger structures of desired geometries. The resulting polymeric microstructures can be transferred from the elastomeric “assembly” substrate to various planar/nonplanar surfaces using sacrificial, water-soluble adhesive films. We demonstrated that this approach is also applicable to the fabrication of heterogeneous structures with functional (e.g., optical or catalytic) properties when the appropriate building blocks were used. We believe 2D assembly substrates, which can operate over large-areas for the assembly of thousands to millions of microstructures simultaneously, represent an exciting route to the microassembly of functional building blocks relevant to numerous fields (e.g., advanced micromanufacturing, microrobotics, nanotechnology, etc.).
11:30 AM - PM04.06.04
MICROPRINCE—Open Access Foundry Pilot Line for Elastomer Assisted Micro-Assembly
Uwe Krieger 2 , Kanchan Ghosal 3 , Gabriel Kittler 2 , Roy Knechtel 1 , Christopher Bower 3 , Ronny Gerbach 1
2 , X-FAB Semiconductor Foundries AG, Erfurt Germany, 3 , X-Celeprint Inc., Durham, North Carolina, United States, 1 , X-FAB MEMS Foundry GmbH, Erfurt Germany
Show AbstractElastomer assisted Micro-Transfer-Printing (μTP) is a demonstrated and versatile micro-assembly technology that has been developed in a laboratory and an industrial environment for over ten years. μTP involves the release, transfer and printing of an array of devices from their growth substrate to a different non-native substrate in a massively parallel manner (i.e. thousands of devices per transfer) with a positioning tolerance less than 1.5 µm, using an elastomeric stamp as the transfer element. X-Celeprint has demonstrated this technology in a wide range of diverse applications spanning from OLED and micro-LED displays to concentrated photovoltaics, sensors, storage and photonics [1, 2]. This technology provides an excellent solution to challenges involving the heterogeneous integration of III-V devices with silicon and other application specific substrates such as engineered substrates, flexible substrates, CMOS wafers and glass substrates. Despite the transformational potential of μTP, no commercial facility is available to scale up the technology to an industrial production level in a microelectronics foundry environment.
This paper will describe a European project, MICROPRINCE, that has the goal of setting up the worldwide first open access foundry pilot line for heterogeneous integration by μTP and demonstrate its capability on five defined target applications. The project includes 13 European partners and will be led by X-FAB MEMS Foundry GmbH, who will set up the pilot line in its cleanroom facilities. The installed pilot and the developed processes will lead to the unique opportunity to transfer R&D results to commercial exploitation. Companies planning to use the technology will now be able to use a foundry to have their products fabricated. This key element is expected to spur rapid adaption of the technology. The successful implementation is expected to lead to a substantial and sustainable growth of micro-assembly related businesses.
11:45 AM - PM04.06.05
Microtransfer Printing Using Composite Stamps with Enhanced Adhesion
Kevin Turner 1 , Helen Minsky 1 , Aoyi Luo 1 , Xing Gao 1
1 , University of Pennsylvania, Philadelphia, Pennsylvania, United States
Show AbstractSoft stamp microtransfer printing utilizing elastomer stamps is a versatile technique for assembly of heterogenous micro- and nano-systems. Microtransfer printing has been used to construct a broad range of devices, including flexible electronics, multi-material photovoltaic cells, and micromechanical systems. Elastomers are well suited as stamp materials in small-scale pick-and-place assembly processes as their low elastic modulus can accommodate roughness on surfaces, thus allowing van der Waals adhesion, and their adhesion is highly rate dependent, which allows adhesion to be tuned via peeling speed. While many stamps used in microstansfer printing are simple elastomer posts, the detailed geometry and compliance of the stamp strongly affect the maximum adhesion that can be achieved and the ability to tune adhesion through factors such as speed and loading direction (e.g., normal vs. shear loading).
Here, we investigate the role of stamp geometry and elastic properties on effective adhesion strength and adhesion tuning via finite element simulations. Based on the mechanics modeling, a composite stamp consisting of a stiff core and thin elastomer shell is shown to offer significantly higher adhesion than a simple homogenous elastomer stamp. The compliance of the elastomer layer allows conformal contact to a range of substrates, while the stiff core alters the detachment mechanics and significantly increases the adhesion strength that be achieved under normal loading. Composite stamps with lateral dimensions of 200 micrometers and below were fabricated and characterized. Effective adhesion strengths of up 1.5 GPa, a >8x enhancement compared to a comparable homogenous elastomer stamp, was measured. The composite stamps were used in microtransfer printing trials to retrieve and print silicon nanomembranes as well as colloidal nanocrystal films. The mechanics modeling, experimental methods, and results will be discussed in this talk.
This work was supported by the National Science Foundation under CMMI-1435745.
PM04.07: Fundamentals for Micro-Assembly
Session Chairs
Wednesday PM, November 29, 2017
Sheraton, 3rd Floor, Fairfax A
1:30 PM - PM04.07.01
Self-Assembly in Confinement—Understanding of Structure and Symmetry of Spherical Colloidal Crystals
Junwei Wang 1 , Michael Engel 1 , Nicolas Vogel 1
1 , Friedrich-Alexander University Erlangen, Erlangen Germany
Show AbstractThe spontaneous organization of individual building blocks into ordered structures is extensively used in nature and found at all length scales, from crystallization processes, via composite materials, to living cells constituting complex tissue. Understanding the relationship between building blocks, environmental conditions, and resulting structure is of fundamental importance for controlling materials properties.
Confining elements imposed upon the self-organizing particles can significantly alter the assembly process and may lead to entirely different colloidal crystals. Especially interesting confinements are emulsion droplets that prevent the formation of periodic structures by introducing boundaries and curvature.
Depending on the drying conditions, such confined assembly processes can lead spherical colloidal crystals with ordered exterior regions and a high amount of disorder in the core region [1] or create very highly ordered structures with symmetries deviating from the typical face-centered cubic packing typically observed for colloidal crystals.
Here, we fabricate monodisperse emulsion droplets to create confinements with a precise number of colloidal particle. We systematically explore the structural details of the resulting assembly structures of the colloidal particles within the confinement and create a detailed phase diagram. We support our model by event-driven molecular dynamics simulations of hard-spheres in a spherical confinement. We finally study structural coloration as an emergent properties of the formed spherical crystals.
References
[1] N. Vogel, S. Utech, G. England, T. Shirman, K.R. Phillips, N. Koay, I. Burgess, M.
Kolle, D. A. Weitz and J. Aizenberg
Color from hierarchy: diverse optical properties of micron-sized spherical colloidal assemblies
Proc. Natl. Acad. Sci. USA 2015, 112, 10845
1:45 PM - PM04.07.02
Development of Bipolar Electrostatic Chuck Module Having Array of Beam Assembly Using Lithography Technique
Seungman Choi 1 , Kazuki Wakabayashi 1 , Kunio Takahashi 1 , Shigeki Saito 1
1 , Tokyo Institute of Technology, Tokyo Japan
Show AbstractWe present a fabrication method of a bipolar electrostatic chuck (ESC) having an array of beam assembly for manipulation of curved dielectric objects such as plastic films and fabrics. The fabricated device can clamp a curved object due to its elastically-deformable beams compliant with an object surface. The device is fabricated by the lithography technique to handle with a microscale object.
An ESC is a handling device using electrostatic force. The ESC draws attention due to its easiness to operate and unaffectedness to atmosphere. The conventional flat ESC has application only to flat surfaced-objects, not to curved-objects, because a contact surface with curved-objects is not large enough to generate intensive adhesive force. In addition, the conventional device works typically only for larger than millimeter-scale object. In this study, in order to manipulate a curved microscale object, we fabricated a bipolar ESC device having array of beam assembly whose tip can be deformed in accordance with surface of the manipulated object. The microscale beams were fabricated by conducting the lithography technique including wet and dry etching processes.
We fabricated the bipolar ESC device by enacting multiple dry and wet etching with a single etching mask for silicon on an insulator (SOI) wafer. The SOI wafer consists of three-layer Si conductor (60 μm)-SiO2 insulator (3 μm)-Si conductor (435 μm). The two Si layers are removed by deep RIE, and the SiO2 layer is removed by wet etching with hydrogen fluoride (HF) acid. The fabricated bipolar ESC device consists of 9 beam-assembly and a support board connected with beams. Each beam has a rectangular cross section, typically 200 μm x 498 μm with a length of 6mm. The beams are slanted at an angle of 45. Each beam is assembled at intervals of 300 μm with its neighbors.
The adhesive electrostatic force generated at the tip of beams assembly was partially compared with the theoretical force calculated with a finite element analysis. When ±150V was applied to bipolar electrodes, the adhesive force was 21.37 mgf, whereas theoretical adhesive force was 63.38 mgf in the same condition. The generated adhesive force per unit effective area, which include the gap between the beams, corresponds to the weight of a quartz glass with thickness of 0.38 mm.
The multiple etching process for three-layers materials was enacted with single etching mask, so that the arrangement of each layer is not necessary after the fabrication. We also suggest the generated force per unit effective area is large enough to clamp dielectric films and fabrics. We expect the fabricated bipolar ESC device with beam assembly is applicable to various field, such as manipulation of film adhesive wearable device and three-dimensional figure of microelectromechanical systems (MEMS).
2:00 PM - PM04.07.03
Residual-Layer-Free Transfer Molding of Mesoscale Structures Enabled by 1D Discontinuous Dewetting
Michael Deagen 1 , Linda Schadler 1 , Chaitanya Ullal 1
1 , Rensselaer Polytechnic Institute, Troy, New York, United States
Show AbstractTransfer molding offers a low-cost approach to large-area nanofabrication in a variety of materials through layer-by-layer assembly. To achieve residual-layer-free filling prior to transfer, a blade meniscus coating process was performed on elastomeric stamps with 1-D patterns of parallel micro-channels and periods ranging from 6 μm to 140 nm. The framework of discontinuous dewetting, described by the wetting of recessed features combined with macroscopic dewetting of ink along the surface of the stamp, was applied to 1-D periodic channels. Changing the azimuthal orientation of the stamp with respect to the blade velocity leads to vastly different wetting morphologies, providing insight into the dominant mechanism for discontinuous dewetting at these size scales and setting this work apart from discontinuous dewetting of 2-D patterns. The critical velocity of the meniscus on patterned surfaces was compared to the critical velocity for a flat surface and was found to follow a similar cubic dependence with respect to the dynamic contact angle. A proposed map of wetting regimes acts as a guide for achieving discontinuous dewetting at maximum throughput, and experimental results were compared to this hypothesis. Residual-layer-free transfer of isolated lines of polydimethylsiloxane (PDMS) onto glass, silicon, and PDMS substrates was achieved through plasma bonding, in addition to multi-layer structures of sub-micron PDMS lines in a woodpile configuration. These results may aid in the development of dip coating, slot die coating, and other roll-to-roll (R2R) processes to produce large-area patterns of isolated features in a range of materials, with potential applications in printed electronics and photonics.
2:15 PM - PM04.07.04
Continuous-Feed Electromechanical Transfer Printing of Graphene
Sanha Kim 1 , Piran Ravichandran Kidambi 1 , Dhanushkodi Mariappan 1 , A. John Hart 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractTwo-dimensional (2D) materials, including graphene, boron nitride and transition metal dichalcogenides, provide a broad range of building blocks for next-generation ultrathin electronics in large-area, flexible and stretchable formats. Accordingly, scalable and reliable transfer of 2D materials from growth substrates to soft, flexible substrates or to other 2D material surfaces is now essential. However, state-of-the art transfer methods typically use wet chemistry and polymer carrier layers, which causes defects and unintended doping, and is unacceptably slow (e.g., several minutes to hours).
Here, we demonstrate high speed roll-based electromechanical transfer of graphene from the metal growth substrate to a target polymer film. Transfer is achieved by first oxidizing the graphene-coated Cu to weaken their adhesion, and then applying a mechanical load (~10-100 N/m), electric field (~1-1.5 kV), and elevated temperature (~100-130 °C) to establish intimate contact and provide a driving force for direct transfer. The contact transfer process is entirely dry, not requiring any adhesives, etchants, or sacrificial transfer layers. We study the effect of surface topography and process parameters on the transfer ratio, and achieve continuous transfer of graphene at speeds of ~0.1-0.2 m/s in a roll-to-plate system. We also show the capability of printing either continuous or patterned graphene layer, on both sides of a dielectric film in a single step.
PM04.08: Innovative Assembly
Session Chairs
Wednesday PM, November 29, 2017
Sheraton, 3rd Floor, Fairfax A
3:30 PM - *PM04.08.01
Heterogeneous Integration of Nanoparticles, Nanowires and Microscopic Chips across Length Scales and Material Boundaries
Johannes Reiprich 1 , Shantonu Biswas 1 , Mahsa Mozafari 1 , Leslie Schlag 1 , Joerg Pezoldt 1 , Thomas Stauden 1 , Heiko Jacobs 1
1 , TU Ilmenau, Ilmenau Germany
Show AbstractThis talk will discuss heterogeneous integration technologies to enable the integration of functional nanomaterials and devices across length scales and material boundaries. The following topics will be presented:
Gas Phase Electrodeposition -- Gas phase electrodeposition is site selective nanoparticle assembly, deposition, and growth process. It replaces the liquid medium and ions in the wet chemical analog with a carrier gas, high mobility gas ions, and charged nanoparticles. The discovered gas phase counterpart enables the site selective deposition in 2 and 3D using pre-patterned surfaces. The process is applied to fabricate nanostructured electrodes, multimaterial / multifunctional sensor arrays, nanoscopic bondwires, SERS enhancement layers, and reactive nanoparticle films.
Fluidic Self-assembly of Microscopic Semiconductor Chips -- The goal of the second process is to enable the assembly and electrical connection of microscopic semiconductor chips on foreign substrates in a massively parallel fashion. The chips are smaller than what can be assembled effectively using robotic pick and place. The physics and applications of fluidic self-assembly will be described. The process has been applied to fabricate solid-state lighting modules in a reel-to-reel fashion.
Metamorphic and stretchable Electronics -- Heterogeneous integration of semiconductor chips on foreign substrates enables the distribution of electronic functions on elastomeric supports, which in turn enables the realization of stretchable and metamorphic electronics. First demonstrators include metamorphic LED and microphone arrays which morph from a planar to a spherical to a cone and box like topologies with corresponding emission and receive characteristics, respectively.
4:00 PM - PM04.08.02
Directed Assembly of Fluorine Free Functional Membranes via Random Distribution of Core/Shell Template Particles
Mario Stucki 1 , Christoph Ruedi Kellenberger 2 , Michael Loepfe 1 , Wendelin Stark 1
1 , ETH Zürich, Zürich Switzerland, 2 , Novamem AG, Zürich, Zürich, Switzerland
Show AbstractInspired by recent bans of fluorinated chemicals[1] along with increasing pressure of international NGOs (Greenpeace) on current market leaders,[2] we investigated the assembly of fluorine free functional membranes. Its role is to protect the wearer from external water, such as rain, while simultaneously water (e.g. sweat) can evaporate outwards keeping the wearer dry. The current state of the art is based on porous polytetrafluoroethylene (PTFE in Gore-Tex®) afforded through stretching. This process, patented in the late 1950`s, should be replaced by more recent membrane assembly methods. With a straightforward templating technology we are able to produce porous polymer films in a controlled and scalable process.[3,4] The adaption of the membrane assembly towards wearable, soft polymers (e.g. polyurethanes) required the balance of suitable porosity against the structural stability. In cases of high template loading, thus high porosity, the polymeric network collapses upon template removal resulting in solid polymer films similar to the ones produced with too little template material. We found a way to overcome this issue by precisely introducing stearic acid at the interface of template and polymeric material. Precoated core/shell limestone particles were used as a carrier for the targeted assembly of the nanoscale surfactant molecule at the desired interface. Precise internal pore coating by stearic acid reduced shrinkage of the porous network upon template removal by about 23 ± 4 %. The apparent water contact angle increased from 88 ± 3° to 101 ± 4°. Specific and precise introduction of stearic acid increased the porosity, the hydrophobicity of the porous system and, surprisingly, tripled the materials waterproofing. Free, uncoated stearic acid did not achieve these desired results. The breathability of the membranes showed excellent levels of 1078 ± 47 g m-2 d-1, which is slightly higher than current market leaders (Gore-Tex ®: 954 ± 18 g m-2 d-1).
The membrane assembly process was transferred from laboratory scale to a continuous roll coating pilot machine, manufacturing membrane at the m2 scale. With about 2.8 m2 of membrane in 30 cm width, a laminate with a commercial fabric was produced and a functional prototype jacket was tailored.[5,6] The shown directed assembly of a functional internally coating of the porous system in membranes can be expanded towards different core/shell combination and their introduction into a multitude of elastomers.
[1] Stockholm Convention on Persistent Organic Pollutants: Geneva, 2009.
[2] Leaving Traces. Greenpeace Int., 2016.
[3] Kellenberger, Luechinger, Lamprou, Rossier, Grass, Stark, J. Membr. Sci. 2012, 387–388, 76.
[4] Hess, Kohll, Raso, Schumacher, Grass, Stark, ACS Appl. Mater. Interfaces 2015, 7, 611.
[5] Stucki, Stark, WATERPROOF AND BREATHABLE, POROUS MEMBRANES 2015.
[6] Stucki, Kellenberger, Loepfe, Stark, J. Mater. Chem. A 2016.
4:15 PM - PM04.08.03
Autoperforation of 2D Materials for Generating Two Terminal Memresistive Janus Particles
Albert Liu 1 , Pingwei Liu 1 , Daichi Kozawa 1 , Juyao Dong 1 , Volodymyr Koman 1 , Michael Strano 1
1 Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractDue to its inherent stochasticity, brittle fracture is seldom used as a nanofabrication method. However, the imposition or templating of a specific strain field can guide fracture along a pre-set design. Herein, we show that this autoperforation provides a means of spontaneous assembly for 2D surfaces. Chemical vapor deposited mono- and bi-layer graphene, molybdenum disulfide (MoS2), or hexagonal boron nitride (hBN) autoperforate into circular envelopes when sandwiching a microprinted polymer spot, allowing lift-off and assembly into solution. The resulting composite microparticles have two independently addressable, external Janus faces that we show can function as an intraparticle array of parallel, two terminal electronic devices. As an example, we print a 0.9 wt% black phosphorous (BP) nanoflake in polystyrene (PS) latex ink into mono-layer graphene sandwich particles, resulting in micro-particles possessing non-volatile, 15 bit memory storage via a spatially addressable memresistor array throughout the particle interior. Such particles form the basis of free floating devices capable of collecting and storing digital information in their environment. The 2D envelopes demonstrate remarkable chemical and mechanical stability during 4 months of preservation in aqueous media. They also survive a highly acidic gastrointestinal environment, as well as aerosolization over 0.3 meters and re-collection. Autoperforation of 2D materials into such envelope structures open the door to precise compositing of particulate devices, extending nanoelectronics into previously inaccessible environments.
4:30 PM - PM04.08.04
Silica Encapsulated DNA-Based Tracers for Underground Reservoir Characterization
Gediminas Mikutis 1 , Claudia Deuber 1 , Lucius Schmid 1 , Anniina Kittilä 1 , Xiang-Zhao Kong 1 , Robert Grass 1 , Martin Saar 1 , Wendelin Stark 1
1 , ETH Zurich, Zurich Switzerland
Show AbstractEnvironmental tracing is a direct and reliable way to characterize aquifers, evaluate underground reservoirs and well as to track contamination. By performing multitracer tests, and translating the tracer breakthrough into tomographic maps, key parameters about the reservoir structure are obtained. However, the tracers used today (fluorobenzoic acids, isotopes, dyes, salts) are not suitable for high resolution geology characterization because only a limited number of unique fingerprints are available (e.g. less than 10 tracer dyes). DNA with its modular design allows generating a virtually unlimited number of unique fingerprints. Its downside is insufficient stability due to microbial activity and chemical stress. Therefore, a material that would protect DNA from external damage, yet keep the advantages of the DNA modular design, would overcome the current tracer limitations.
We developed a bottom-up approach to encapsulate DNA into silicon oxide particles by electrostatically assembling short double-stranded DNA sequences onto quaternary amine-functionalized silica nanoparticles, and then growing a silicon oxide shell on the surface using Stöber method.[1] The final encapsulates with a narrow size distribution at 150 nm (tunable) showed increased thermal, light, and chemical stability over extended periods of time. Furthermore, DNA could be quantitatively recovered by dissolving SiO2 shells using a mild fluoride solution (250 ppm). The breakthrough curves of these layer-by-layer assembled DNA/silica particles in porous sand columns had slightly earlier and sharper breakthroughs than a traditional solute tracer uranine because of the size exclusion effect: larger particles result in earlier breakthroughs. The surface charge was found to not influence the particle mobility and deposition. Experiments in an unconsolidated aquifer confirmed the preferential flow path theory, since the particle tracers again resulted in an earlier and sharper peak than solute tracers.[2, 3]
In conclusion, silica micro-assembly was proven to improve the DNA thermal, light, and chemical resistance, making the new material an ideal non-reactive tracer. Simultaneously performing multitracer tests using a large number of unique DNA-based microparticle tracers allows to better characterize aquifers, oil and geothermal reservoirs or to track multiple sources of contaminants with high resolution.
[1] Paunescu, D., Fuhrer, R. and Grass, R. N. (2013), Protection and Deprotection of DNA—High-Temperature Stability of Nucleic Acid Barcodes for Polymer Labeling. Angew. Chem. Int. Ed., 52: 4269–4272.
[2] Mikutis, G., Deuber, C. A., Schmid, L., Kittilä, A., Grass, R.N., Saar, M. O., Stark, W. J., Silica encapsulated DNA-based tracers for underground reservoir characterization, in preparation.
[3] Deuber, C.A., Kittilae, A., Somogyvári, M., Mikutis, G., Bayer, P., Kong, X-Z., Stark, W. J., Saar, M. O., DNA-labeled silica nanoparticles as subsurface fluid flow tracers, in preparation.
4:45 PM - PM04.08.05
Two-Dimensional Material Based Layer Transfer of Thin-Film Devices
Yunjo Kim 1 , Kyusang Lee 1 , Chanyeol Choi 1 , Yi Song 1 , Jared Johnson 2 , Wei Kong 1 , Shinhyun Choi 1 , Kuan Qiao 1 , Ibraheem Almansouri 3 , Eugene Fitzgerald 1 , Jing Kong 1 , Alexie Kolpak 1 , Jinwoo Hwang 2 , Jeehwan Kim 1 , Babatunde Alawode 1 , Christopher Heidelberger 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 , The Ohio State University, Columbus, Ohio, United States, 3 , Masdar Institute of Science and Technology, Abu Dhabi United Arab Emirates
Show AbstractVan der Waals epitaxy has gain great interest for epitaxial growth of two-dimensional (2D) materials as it allows for substantially relaxed lattice matching conditions for single-crystalline growth. However, the mechanism to achieve planar growth of three-dimensional (3D) semiconductor films on 2D films have seen limited success, in part due to the limited understanding of the interaction between the 2D material substrate and 3D epitaxial film. In these studies, researchers have focused solely on the 2D film as the epitaxial template for growth. In our study, we demonstrate that epitaxial registry can be induced remotely from the substrate to the epitaxial layer through monolayer graphene. Due to the atomic-thickness and weak van der Waals interaction on the surface of graphene, semiconductor adatoms on its surface can be made to register to the crystalline substrate underneath graphene and self assemble to form single crystalline semiconductor films. This work introduces a novel epitaxial growth mechanism of semiconductor films on graphene-coated substrates, termed remote epitaxy. We investigate the conditions that facilitate the remote interaction and self-assembly of semiconductor adatoms in the presence of graphene. In addition, due to the weak van der Waals interactions on the surface of graphene, a well-defined cleavage plane forms at the interface, enabling facile mechanical exfoliation of the epitaxial film. The exfoliation process yields a clean interface allowing for the graphene-coated substrate to be re-used for continuous fabrciation of thin-film semicondcutors. This novel layer transfer process, termed two-dimensional material based layer transfer (2DLT), opens apportunities to fabricate a variety of thin film semiconductors, while potentially saving costs associated with semiconductor wafers by offering reusable graphene-coated substrates. Reusable graphene-coated substrates will have profound impact especially in the field of non-silicon electronics and photonics since the wafers themselve contribute significantly to the cost of device fabrication.
PM04.09: Poster Session: Micro-Assembly
Session Chairs
Thursday AM, November 30, 2017
Hynes, Level 1, Hall B
8:00 PM - PM04.09.01
Dry Press-Assembled Monodisperse Spheres
Cefe Lopez 1 , Denise Montesdeoca 1 , Farzaneh Bayat 1 , Andre Espinha 1 , Carlos Pecharromán 1 , Alvaro Blanco 1
1 , Instituto de Ciencia de Materiales de Madrid (ICMM, CSIC), Madrid Spain
Show Abstract
We present a new method to fabricate silica photonic glasses from powder by using a uniaxial press in dry conditions [1]. This novel procedure is much faster than the traditional ones and is capable to yield thick solid, freestanding photonic glasses [2] that show resonant optical modes. This novel material lends itself useful in the field of granular media as well as in disorder photonics. The packing process and the flow of particles under pressure can be studied in pressed photonic glasses. We have demonstrated by total transmittance and coherent back scattering measurements that the applied pressure does not affect the resonant optical response but has sizable impact on the mechanical stability of the resultant system. A simple but powerful phenomenological model of forward scattering has been developed that accounts for the ripples in the scattering cross section. Further atomic layer deposition infiltration, of extreme accuracy, allows the fine tuning of their optical properties [3]
[1] D. Montesdeoca, et al. Part. Part. Syst. Charact. 33, 871–877 (2016).
[2] P.D. García, et al. Adv. Mater. 19, 2597–2602 (2007).
[3] A. Espinha, et al. Part. Part. Syst. Charact. 33, 352–357 (2016).
8:00 PM - PM04.09.03
Self-Assembled 3D Split-Ring Resonators as Tri-Axial Inclinometers
Kriti Agarwal 1 , Chao Liu 1 , Daeha Joung 1 , Jeong-Hyun Cho 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show Abstract
Optical inclinometers have been investigated for the development of small scale, low-on chip power sensors that can remotely sense the angle of rotation for application in microbots and nanosatellites. However, they suffer from a limited range of < 45° as well as the need for three individual sensors for tri-axial sensing that can reduce packaging density and cause interferences. Similarly, split-ring resonator (SRR) based inclinometers suffer from the angular dependence of the SRR transmission response which limits the sensing range of remote monitored SRR-based optical inclinometers to 0°-180°. The 2D nature of the planar SRRs fails to overcome the limited sensing range of 180° along only one axis. However, by using a novel polymer hinge based origami-like self-assembly, 2D planar SRR structures can be converted to 3D SRRs with the resonators present on each face of a cubic structure. Through the patterning of twisted SRR structures of three different lengths on the faces of a polymer based cubes, the frequency response can be achieved with three peaks representing the resonant frequency of each of the chosen SRR lengths. The overall transmission response obtained is fully anisotropic such that the transmission amplitude for all the three peaks does not repeat itself for any two values of the angle of incidence along the three coordinate axes. By determining the transmission amplitude of the three peaks, tri-axial measurements of the angle of rotation up to 360° can be carried out which are needed to determine the position and orientation of the targeted object. The fully anisotropic SRR provides the ability for small scale, low power, remote, and interference-free tri-axial detection of the rotation angle especially in medical microbots where the low-power consumption and small area is highly desired.
8:00 PM - PM04.09.04
Morphological Control of Melting Gel Materials by Electrospray Deposition
Lin Lei 1 , Jihyun Ryu 1 , Kutaiba Marzoki 1 , Daniel Sullivan 1 , Muthanna Kareem 1 , Lisa Klein 1 , Assimina Pelegri 1 , Jonathan Singer 1 , Gabriela Rodriguez 2 , Andrei Jitianu 2
1 , Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States, 2 , Lehman College-CUNY, Brooklyn, New York, United States
Show Abstract
Melting gel materials are oligomeric silsesquioxanes that possess glass transition temperatures near room temperature and a consolidation temperature >150C, above which they irreversibly transform into modified silica glass. Melting gels can be processed as a thermoplastic melt into a desired form and then converted into a permanent structure based on this property. In our study, melting gel materials are processed by electrospray deposition in order to investigate the kinetic behavior arising from different experimental conditions and how these affect the final morphologies of melting gel films. Due to the electrostatic breakup mechanism present in electrospray, the resulting sprays possess uniform droplets down to hundreds of nanometers. By using dilute loadings, these microdroplets can deliver extremely small quantities of material at a continuous rate and incorporate fillers to change the properties of the spray and the functionality of the final structures. Control of spray composition, substrate temperature, flow rate, and collection distance, translates to tuning of the dynamic evolution of solvent evaporation and melting gel consolidation. The results reveal that these can be used to controllably tune surface structure from dense, to cellular, to superhydrophobic fractal coatings. Nanoindentation tests show that the mechanical properties of the constituent melting gel are also affected by these parameters. In addition, manipulation of charge dissipation during the deposition also results in the ability to limit the extent of spray as a means to gain control over the coating thickness.
8:00 PM - PM04.09.05
Optimization of Jet Physics for Electrodeposition-Based Metal 3D Printing
Marco Stefancich 2 , Matteo Chiesa 1 , Harry Apostoleris 1 , Omar Almelhi 1 , Saba Khan 1 , Lutfiye Ozer 1 , Sverre Minnesjord 3
2 , Dubai Electricity and Water Authority, Dubai United Arab Emirates, 1 , Khalifa University of Science and Technology, Abu Dhabi United Arab Emirates, 3 , Fluid Metal 3D, Skien Norway
Show AbstractMetal 3D printing based on localized jet-assisted electrodeposition has the potential to play an important role in metal 3D printing. The high mass transfer rate and the disruption of the limiting layer at the jet impact point, allow for localized high rate electrodeposition. While such metal-printer prototypes have recently been demonstrated, significant optimization remains to be done. The key to this process will be optimizing the parameters of the print jet, which enables the high speed mass transfer required for high speed printing. We discuss here the physics and such deposition and present a predictive model of deposition speed dependence on jet characteristics based on the hydrodynamic mass transfer theory of jet electroplating.
8:00 PM - PM04.09.06
Electrical and Optical Anisotropy of Coatings of Flow-Aligned Silver Nanowires
Ye Xu 1 2 , Dengteng Ge 3 2 , Gabriel Calderon-Ortiz 2 , Annemarie Exarhos 2 , Jay Kikkawa 2 , Shu Yang 2 , Aujun Yodh 2
1 , Beihang University, Beijing China, 2 , University of Pennsylvania, Philadelphia, Pennsylvania, United States, 3 , Donghua University, Shanghai China
Show AbstractConductive and transparent coatings consisting of silver nanowires (AgNWs) have been suggested as a promising candidate for conducting components in emerging flexible electronics applications. The electrical and optical properties of such AgNW coatings depend strongly on the structure of nanowire networks formed by various processing methods. In this work, we deposit AgNW coatings with various degrees of alignment and study how the alignment of nanowires affects the electrical and optical anisotropy in AgNW coatings. Specifically, we introduce a robust method to prepare ultra-thin coatings of well-aligned AgNWs on glass substrates up to centimeter scale; the method utilizes the rapid flow of AgNW suspensions through a confined geometry. The angle-dependent sheet resistance of the coatings is measured, and large anisotropy in surface conductivity is found to characterize the aligned AgNW networks. We also find angle-dependent intensity and spectrum for transmitted, reflected, and scattered visible light by aligned nanowire coatings, resulting in different transparencies and colors depending on the orientation relative to the polarized light source.
8:00 PM - PM04.09.07
Research on Controlled Self-Assembly of Fluorescent Block Copolymers Drive by π-π Interactions
Liang Han 1 , Feng He 1
1 , Southern University of Science and Technology, Shenzhen China
Show AbstractIn recent, nanoscale 2D (two-dimensional) self-assembled architectures have drawn a great deal of attentions as a result of their unique properties caused by their ultrathin and flat morphologies. Over the past few years, various 2D micro-/nano- structures have been reported constructed by inorganic metal salts, organic molecules, proteins and block copolymers (BCPs). In these methods of preparing 2D assembled nanostructures,crystallizationdriven processes play a vital role, and the shapes of these formed 2D nanostructures are thus controlled by crystal unit cell symmetry. Therefore, 2D micro-/nano- architectures with high symmetry, as exemplified by equilateral triangle-, square-, hexagon- and circular-shaped assembled structures, are still rarely explored,and achieving them maybe need other noncrystallization approaches, for example, Van der Waals' force, affinity / hydrophobic interaction, hydrogen bonds, π-π interactions and so on. However, considerable control over the structures of 2D BCP micelles is still hardly to realize and noncrystalline 2D regular architectures are still rarely obtained. To acquire colloidally stable 2D micro-/nano- structures with uniform structures, controlled shapes and dimensions remains a keychallenge.
Poly(p-phenylenevinylene) (PPV) or OPV is a classic kind of π-conjugated materials with fascinating optical and electronic properties. The long conjugated backbones make PPVs possess strong intermolecular packing tendency. These sheet-forming polymeric blocks were always utilized to prepare appropriate BCPs as building blocks for supramolecular self-assembly. However, most of the reported morphologies of PPV were common 1D micro-/nano- structures that were cylindrical or fiber-like. We combine PPV blocks and poly (2-vinyl pyridine) (P2VP) to build amphiphilic diblock copolymers PPV12-P2VPn with “sheet-coil” type, and colloidally stable 2D fluorescent square micelles were formed in selective solvent isopropanol. Low dispersities and dimensional control of the 2D square micelles were realized by adjusting the block ratio of P2VP/PPV and solution concentration. Furthermore, it was found that the assembly process of 2D micelles in solution was closely related to the temperature and intermolecular π-π interaction and the perpendicular packing angle play a vital role on the formation of square films.
8:00 PM - PM04.09.08
Carrier Transport in GaAs-Graphene-GaAs Heterostructures by Tight-Binding Calculations
Chanyeol Choi 1 , Yunjo Kim 1 , Sunwoo Lee 2 , Janghoon Woo 2 , Yongmin Baek 2
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 , Yonsei University, Seoul Korea (the Republic of)
Show AbstractThe lattice mismatching in epitaxial growth has been an obstacle to homo-epitaxy. Recently, we discovered that the epitaxial growth of crystalline material can be achieved through the simplest two dimensional materal, graphene. By transferring single layer graphene on crystalline materials, lattice matching requirement is relaxed and homo-epitaxy is obtained successfully. This is because a weak van der Waals effect of graphene is not strong enough to block the potential field of host substrates. Since epitaxy-grown films are released at the surface between graphene and epitaxy-grown semiconductor, we can constantly reuse the host substrates. In this regard, graphene has become an excellent candidate for reducing the cost of III-V semiconductors. We further investigate carrier transport of vertical heterostructure, specifically GaAs-graphene-GaAs which is prior to the release process, by using tight-binding approach. Due to the coupling between graphene and semiconductor, charge transport and transmission coefficient are influenced. Also, our energy dispersion result shows that GaAs band dispersion retains its original curvature in k-space although transmission is suppressed slightly. This indicates single layer graphene can be considered as ‘transparent layer’, even though screening effect from graphene van der Waals potential field exists. This work will help us to understand how much graphene affects the epitaxial growth and how tightly the grown semiconductor are bound to graphene.
8:00 PM - PM04.09.09
Self-Assembled Growth of Sr(Ti,Fe)O3-CoFe2O4 Epitaxial Nanocomposite Thin Films by Pulsed Laser Deposition
Dong Hun Kim 1 , Tae Cheol Kim 1 , Seung Han Lee 1 , C. A. Ross 2
1 , Myongj University, Yongin Korea (the Republic of), 2 , MIT, Cambridge, Massachusetts, United States
Show AbstractOxide nanocomposite thin films have been extensively explored, in particular BiFeO3-CoFe2O4 (BFO-CFO) self-assembled nanocomposite in which a ferrimagnetic spinel phase (CFO) grows epitaxially as pillars within an immiscible ferroelectric antiferromagnetic perovskite phase (BFO). The nanocomposite shows a strong out-of-plane anisotropy as a result of both the shape anisotropy of the pillars and the dominant magnetoelastic anisotropy of the CFO under out-of-plane compression due to epitaxy with the BFO matrix. However, there is little work on oxide nanocomposites in which both materials are ferro- or ferrimagnetic. Such nanocomposites could combine the properties of both phases, and exchange coupling at the interfaces may lead to nanocomposites with exchange-spring behavior.
In this work, Iron-substituted SrTiO3-CoFe2O4 nanocomposite thin films were grown by pulsed laser deposition on (001) SrTiO3 substrates, and their structure and magnetic properties were compared with those of single phase films. Both CoFe2O4 thin films grown in oxygen and under vacuum exhibited an in-plane magnetic easy axis, but films grown in vacuum exhibited polycrystallinity and additional metallic phases. Sr(Ti,Fe)O3 grown under high vacuum conditions showed an out-of-plane easy axis, whereas films grown in oxygen had no ferromagnetism. Nanocomposite thin films grown under high vacuum exhibited a terraced microstructure with out-of-plane easy axis. On the other hand, nanocomposites grown in oxygen exhibited two-step switching and much higher saturation magnetization. The results are consistent with dominant magnetoelastic anisotropy.
This investigation shows that nanocomposites can be fabricated with two magnetic oxide phases to give a two-step hysteretic response, and we conclude that lattice strain at the STF20-CFO vertical interface plays a crucial role in controlling the structure and magnetic properties of nanocomposites.
8:00 PM - PM04.09.10
Precise Three-Dimensional Assembly of Aligned Carbon Nanotubes by Direct Laser Writing
Ying Liu 1 , Wei Xiong 2 , Lan Jiang 3 , Jean-Francois Silvain 4 , Yong-Feng Lu 1
1 , University of Nebraska–Lincoln, Lincoln, Nebraska, United States, 2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan China, 3 School of Mechanical Engineering, Beijing Institute of Technology, Beijing, Beijing, China, 4 , Institut de Chimie de la Matière Condensée de Bordeaux, Bordeaux France
Show AbstractCarbon nanotubes (CNTs) exhibit remarkable mechanical, electrical, thermal, and optical properties, which are not only sensitive to their dimensions but are also highly anisotropic. We have developed a new approach for the assembly of well-aligned multiwalled CNTs (MWNTs) by direct laser writing via two photon polymerization (TPP) stereolithography combined with thermal annealing. Highly uniform and stable composite photoresists were prepared by directly incorporating MWNTs up to 0.2 wt% into thiol-acrylate resins. Various functional 3D micro/nanostructures including woodpiles, microcantilevers, suspended microbridges, microcoil arrays, and photonic crystals have been successfully fabricated by TPP. The final composite structures contained well-dispersed and aligned nanotubes embedded inside polymer matrix, which were revealed both by destructive thermal annealing and nondestructive polarized Raman Spectroscopy. The orientation of MWNTs in the composites was determined by laser scanning direction and was ascribed to spatial confinement effect as well as volume shrinkage. The composite micro/nanostructures exhibit the combined properties of being flexible, transparent with high electrically conductivity and enhanced mechanical strength. The CNT alignment also generates strong anisotropy in the electrical properties. Precise MWNTs assembly of ~100 nm spatial resolution has been achieved by selective thermal evaporation of the polymer component out of the composites. Our work paves the way towards printing of MWNTs into arbitrary 3D micro/nano-architectures, which is promising for a broad range of device applications, including MEMS/NEMS, 3D electronics, integrated optics, biomimetics, and metamaterials.
8:00 PM - PM04.09.11
Transferable Arrays of Nanomaterials Fabricated by Directed Self-Assembly of Diblock Copolymers
Heejung Kang 1 , Jonghyuk Jeon 1 , Byeong-Hyeok Sohn 1
1 Chemistry, Seoul National University, Seoul Korea (the Republic of)
Show AbstractDiblock copolymers composed of two different polymers spontaneously assemble into periodic nanodomains, of which the size and morphology can be controlled by the molecular weight and composition of copolymers. Their thin films have been utilized for fabrication of nanomaterials. Furthermore, nanodomains of diblock copolymers can be aligned in specific orientation by the directed self-assembling technique. In this study, we employed nanodomains of diblock copolymers as templates for arrangement of ex-situ fabricated nanomaterials as well as for in-situ synthesis of nanomaterials. The orientation of nanomaterials over large area was mainly controlled by the directed self-assembling process of diblock copolymers in order to produce arrays of nanomaterials. In addition, we were able to transfer arrays of the fabricated nanomaterials onto flexible substrates by detaching them from the original substrate. We also investigated the structures and physical properties of arrays of nanomaterials before and after transferring procedure.
8:00 PM - PM04.09.12
A Polymer Janus Particle Having Ring Arrays of Gold Nanoparticles Aligned at Its Equator
Yutaro Hirai 1 , Hiroshi Yabu 2
1 , Tohoku University, Sendai Japan, 2 , WPI-AIMR, Sendai Japan
Show AbstractJanus particles, whose hemispheres are hydrophilic and hydrophobic, form Pickering emulsion, in which Janus particles are arranged at the emulsion interface as stabilizers. Janus particles are also applicable to display elements of electronic paper devices. Furthermore, Janus particles containing chemical catalysts on the one side of the surface have been attracted attentions as self-propelled micro-stirrers. On the other hand, In these previous reports, each phase of Janus particle was functionalized. There are few reports focused on modification of the interface of Janus particles.
Gold nanorings have strong plasmon resonance horizontal to the ring surface, and gold nanoring arrays have been employed to ultra-sensitive SERS biosensor substrates. It is also reported that some chemical reactions can be catalyzed by strong electromagnetic field generated by plasmonic resonance of gold nanostructures. Thus, it is vital to introduce gold nanorings to Janus particles, which can be applicable to sensing and catalyze chemical reactions occurred at the oil-water or air-water interfaces by using a coupling of plasmon resonance among Janus particles.
We have been reported that polymer particles having phase separated structures can be prepared by adding a poor solvent to block copolymer or homopolymer blend solution followed by solvent evaporation (Self-Organized Precipitation, SORP). Furthermore, we have reported that gold nanoparticles (AuNPs) can be introduced selectively by using polymer-coated AuNPs, which coated with polymer having affinity with each phase. It has been reported that circular AuNPs arrangement composed of appropriate intervals such that the surface plasmon of AuNPs couple each other exhibit simillar extinction spectrum intensity and wavelength as those of gold nano rings. In this report, AuNPs were arranged in a ring shape at the polymer-polymer interface of Janus particle by mixing AuNPs coated with two kinds of polymers constituting Janus particles into the polymer solution.
AuNPs are coated with amino terminated polystyrene (PS-NH2) and/or amino terminated polybutadiene (PB-NH2) and then mixed with PS and PB tetrahydrofran (THF) solution. After evaporation of THF, Janus particles having Au NPs were obtained. PS-NH2 coated AuNPs and PB-NH2 coated AuNPs were induced in PS and PB phase, respectively. On the other hand, when AuNPs were coated with both PS-NH2 and PB-NH2 (mixing ratio=1:1), the AuNPs were aligned at the equator of Janus particle. By covering AuNPs with two kinds of polymers, the surface tension of the polymer-coated AuNPs became intermediate value of the two kinds of polymers. Finally, we also induced Au nanorods(AuNRs) to Janus particles. Localized surface plasmon resonance (LSPR) of short axis faced AuNRs alignment show higher enhanced LSPR than AuNPs. When PS-NH2 and PB-NH2 (mixing ratio 1: 1) coated AuNRs were induced to Janus particles, AuNRs aligned and crossed vertically to the polymer interface in Janus particles.
8:00 PM - PM04.09.13
Low Temperature Soldering Surface-Mount Electronic Components with Hydrogen Assisted Copper Electroplating
Sabrina Rosa 1 , Arash Takshi 1
1 , University of South Florida, Tampa, Florida, United States
Show AbstractStandard electronic assembly is based on soldering electronic components on a printed circuit board (PCB). The soldering process requires melting the soldering materials at an elevated temperature. With the recent developments of flexible and wearable electronics, a challenge is to solder elements at low temperatures for not damaging the plastic or fabric substrates. Copper growth for the development of electroplating technique as a low-temperature soldering procedure represents a useful method for the formation of metal deposits, allowing modification of the thickness and morphology of the soldering joints. To accelerate the soldering process we have employed the hydrogen assisted electroplating (HAE) method to solder a surface-mount component to a PCB track at room temperature. The deposition of the plating material has been demonstrated by creating a junction bridge across a ~1 mm gap between two electrodes on a patterned PCB board and also between a track and an electronics component terminal. The experiment was designed by making a small electrochemical cell around the gap on the PCB. The deposition of copper was studied at various voltages ranging from -1.0V to -1.3V. Formation of irregular deposits by electrodeposition were investigated. During the experiment electrolysis was observed, allowing hydrogen ions to interact with Cu2+ ions in order for the plating to take place. The hydrogen bubbles released after the electrolysis caused the structure of the electroplated layer to be more porous, but with a similar conductivity as solid copper and a remarkable mechanical strength suitable for use as interconnect on PCBs. A junction between the two electrodes was reported to occur in less than 1 minute, this result ensures the participation of the electrolyte and the copper as the plated material. The morphology of copper deposits based on the interaction with hydrogen was examined using a Scanning Electron Microscopy (SEM) technique. Further improvement is required to solder components by using this low temperature soldering technique, which also helps altering the surface of the samples providing benefits reducing the cost of production.
8:00 PM - PM04.09.14
Large Angle Electrothermal Micromirror Array
Corey Pollock 1 , David Bishop 1
1 , Boston University, Boston, Massachusetts, United States
Show AbstractThere are many applications including telecommunication, display technologies, and smart lighting that benefit from micromirror arrays. Two of the most successful commercial arrays are the Digital Micromirror Device by Texas Instruments for projector displays and the LambdaRouter by Lucent for telecommunications. These devices were mass produced, however they had relatively low angular range (<20° optical). Academic research is consistently working towards mirror arrays with improved angular range, speed and optical efficiency. Although many mirror designs in research have larger angular ranges, they use fabrication techniques that are not currently scalable for large quantities.
We have developed a tip-tilt mirror driven by electrothermal bimorphs capable of steering a beam ±40° [1]. This mirror uses the MEMSCAP PolyMUMPs process which is inherently scalable for large quantities. By utilizing a similar bimorph-mirror design, we have created a 2x2 micromirror array capable of large tip-tilt angles that can be mass produced using existing technology. This has the potential to vastly improve commercially available arrays and benefit many applications such as telecommunications, display technologies and smart lighting.
[1] J. Morrison, M. Imboden, T.D.C. Little, D.J. Bishop, “Electrothermally actuated tip-tilt-piston micromirror with integrated varifocal capability,” Optics Express 23, 9555-9566 (2015).
8:00 PM - PM04.09.15
Controlled Adsorption of Biocompatible Polymers to Surfaces of Polyphenol Crystals
Gyuhyeong Choe 1 , Jonghwi Lee 1 , Soo Min Bae 1
1 , Chung-Ang University, Seoul Korea (the Republic of)
Show AbstractRecently, anti-oxidant materials such as polyphenols have received great attention in many science and engineering areas such as cosmetic, pharmaceutical, and adhesive areas. Similar to dopamine, natural polyphenols have phenol and catechol functional groups, and in most conditions, they have significant bioavailability. However, their physicochemical properties have seldom been controlled for a specific target application. For example, the initial abrupt release of polyphenol crystals which can cause adverse effects has seldom been suppressed. Crystal engineering could provide a convenient tool to control the properties of materials with minimum modification of the intrinsic properties. In this study, we developed a novel technique to talior the properties of polyphenols using limited amounts of polymers, polymer-directed crystallization, which is based on the controlled surface adsorption mechanism of polymers onto growing crystal surfaces. Various polymers generally regarded as safe were utilized for the cooling crystallization of polyphenol, and catechin was chosen as a model polyphenol. Mixed solutions of catechin and various polymers underwent the controlled nucleation and growth processes. When polyethylenimine (PEI), hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) were used, the habits of catechin crystals were significantly changed due to surface adsorption of polymers. Their X-ray diffraction results also showed significant changes in crystallinity, compared to recrystallized catechin crystals. In SEM observation, recrystallized catechin crystals without a polymer have needle morphology of an average length of 80 um. On the other hand, the cases of PEI, HPMC and PVA showed average length of only 2 um. FT-IR investigation revealed the existence of the adsorbed layers of polymers on the surfaces of crystals and significant interactions between polymers and catechin. In the release tests of crystals using simulated instetinal fluid sine pancreatin, catechin with PVA and HPMC showed 50% lower initial release patterns compared to recrystallized catechin without a polymer. Surprisingly, catechin with PEI showed 90% sustained inital release pattern, although it has a smaller average particle size. These results promised that the polymer-directed crystallization method could be effective for controlling the propertis of polyphenols with a limited amount of polymers, which could find promising future applications in many future application areas.
8:00 PM - PM04.09.16
Comparison between Transferred Patterns by Deformation Method of Stretchable Elastomers
Seunghang Shin 1 , Yeonho Jeong 1 , Hyunmin Choi 1 , Yoon Gyo Jung 1 , Young Tae Cho 1
1 , Changwon National University, Changwon-si Korea (the Republic of)
Show AbstractGenerally, in the printed electronics processes, there is a limitation that nm-class pattern transfer can not be performed. Many studies have been conducted to reduce line width, a kind of that applies printing process using elastic restoration.
In this study, a reduced pattern was fabricated by applying elastic deformation to reverse offset printing process. Tension and reduction process of the stretchable elastomer to which the pattern was transferred was changed. Subsequently, changes in fabricated patterns were compared and analyzed. One method is Stretching both sides of stretchable elastomer with microscale linear pattern printed. Elastomer substrate with pattern transferred is increased, the line width of the pattern becomes thinner. However, when the deformation exceeds a strain of a specific numerical value, crack was occurred. Another method uses elastic restoration of stretched elastomer. As the area of the elastomer substrate decreases, the line width of the pattern also decreases. Therefore, Aspect ratio was increased. Patterns fabricated by these two methods were compared by SEM.
8:00 PM - PM04.09.17
Photocatalysis Using Self-Assembly Erdite Phase Particles in Biomimetic Supraparticles
Luiz Gorup 1 2 , Emerson Camargo 1 , Gleiciani de Queiros Silveira 2 , Naomi Ramesar 2 , Douglas Montjoy 2 , Nicholas Kotov 2
1 , Federal University of Sao Carlos, Sao Carlos Brazil, 2 Chemical Engineering, University of Michigan–Ann Arbor, Ann Arbor, Michigan, United States
Show AbstractThe extensive variety of available biological nanostructure has inspired promising strategies to fabricate biomimetic nanostructured hybrid materials. Biomimetic systems can be used as a template that enables innovative alternatives to overcome the limitations of conventional synthesis methods. In this work, we use biotechnology with materials chemistry to fabricate self-organized systems of erdite nanoparticles to form pollen-shaped supraparticles (SPs). Supraparticles of 5 µm with pollen morphology was assembled and surface showing spines which provided a surface area of greater than 8.2 m2 / g. The nanostructures were formed by altering the ionic strain of the synthesis solution. The pollen morphology prevents aggregation of the particles and promotes high surface area which allows the supraparticles to exhibits excellent photocatalytic properties with the assistance of H2O2 for degradation of methylene blue (MB). In the reaction solutions, a concentration of 25 µg/mL of methylene blue was degraded completely by the 0.5 mg/mL SPs assisted by 6.0 mg/mL H2O2 within 4 minutes, the catalytic efficiency of the SP maintained 100% up until 12 cycles. These excellent photocatalytic property is owing to the synergistic efect of SP and H2O2. The SP exhibits high specific surface area, high adsorption capacity and low recombination of the photo-generated electrons and holes due to the shape of nanostructure and erdite phase property.
8:00 PM - PM04.09.18
Combination of PEG Hydrogel and Hydrophobic PDMS Rubber by Self-Assembly
Yunho Cho 1 , Jonghwi Lee 1
1 , Chungang University, Seoul Korea (the Republic of)
Show AbstractAfter more than four decades of research and development, various hydrogels with beneficial hydrophilic properties are available for many applications now. However, the weak mechanical properties of hydrogels often limit their application. For example, poly(ethylene glycol) (PEG) has outstanding antifouling property, but it cannot be used for actual coating layers on commercial parts because of its low mechanical durability. Composites of well-controlled structures could be effective solutions, which can improve the merit of each materials and to complement its shortcomings. Herein, we developed unique composite materials of PEG and polydimethylsiloxane (PDMS), which can form durable coating layers on any polymeric surfaces. PEG hydrogel films having a continuous open pore structure were first prepared by a self-assembly technique, directional melt crystallization of solvent and subsequent solvent sublimation. Then, we infiltrated PDMS into the porous PEG hydrogels. To improve the adhesion between the composite coating layers and substrates, substrate polymer surfaces were also pretreated with the directional melt crystallization method. The resulting porous surfaces of substrates allow PDMS infiltration, resulting in strong interface between the composites and the substrates. The structure of composites was confirmed by scanning electron microscopy. Porous PEG hydrogels had 20 µm width and 20~80 µm length of pores, which remain intact after infiltration. Interfaces between different phases showed ordered interlocked finger structures, indicating improved adhesion properties. Energy dispersive X-ray spectroscopy distinctly confirmed the ordered location of PEG and PDMS phases in the composites. Micro-indentation measurement revealed that a composite of PEG/PDMS = 10/90 wt% showed 269 kPa of elastic modulus and no hysteresis. Its low water contact angle, 23°, proved the hydrophilic properties of PEG contribute to the surface properties of composites: Infiltrated PDMS did not completely cover the surface of composites. Because both PEG and PDMS are well-known materials having good antifouling properties, this co-continuous structure of PEG and PDMS has potential for antifouling applications.
8:00 PM - PM04.09.19
3D Additive Manufacturing of Micron Scaled Metal Structures Using FluidFM Technology
Cathelijn van Nisselroy 1 , Luca Hirt 1 , Alain Reiser 2 , Ralph Spolenak 2 , Janos Voros 1 , Tomaso Zambelli 1
1 Institute for Biomedical Engineering, ETH Zurich, Zurich Switzerland, 2 Laboratory for Nanometallurgy, ETH Zurich, Zurich Switzerland
Show AbstractFabrication of tailored metal layers, patterns and structures has been a topic of growing interest in the last decade. Applications of these custom-made designs can be found in various fields like optics, (bio)sensing, (micro)electronics and microelectromechanical systems (MEMS). Where traditional fabrication methods, such as stereolithography, are often time consuming and limited to 2D arrangements, additive manufacturing (AM) allows for the fabrication of structures without geometrical constraints. So far, however, solid AM methods for the purpose of manufacturing metal structures have only been established at the macro scale. The limitation of these AM techniques, such as the focused laser beam method and the metal powder particle melting process, is their finite resolution (~100 µm), which is inadequate for (sub)micron scaled manufacturing.
Here we report the use of the Fluid Force Microscope (FluidFM), a technique enabling voxel by voxel printing of metal structures with sub-micron resolution. Each voxel is printed by confined electroplating under the apex of the force-controlled nanopipette, and all subsequent voxels are deposited similarly in an automated, layer-by-layer fashion due to the system’s integrated force-feedback. With the FluidFM we have successfully demonstrated the one-step, mask-free microprinting of a wide variety of pure 3D copper geometries. Currently this technique is not only used to investigate the 3D deposition of other metals, such as gold and platinum, but also to study the possibility of multi-material printing at the micron scale.
8:00 PM - PM04.09.20
Sequential Electrophoretic Depositions for Gradient Colloidal Crystals and Inverse Opals
Pei-Sung Hung 1 , Chen-Hong Liao 1 , Shih-Cheng Chou 1 , Yu-Szu Chou 1 , Po-Chun Hsieh 1 , PuWei Wu 1
1 , National Chiao Tung University, Hsinchu Taiwan
Show AbstractThe fabrication of colloidal crystals and inverse opals has attracted considerable attentions for many years due to their unique physical and chemical characteristics. For example, a desirable inverse opaline structure exhibits adjustable internal pores that are fully interconnected, and therefore reveals promising potentials in chromatography, catalysis, sensing, and separation. In this work, we demonstrate a fabrication scheme that employs sequential electrophoresis of polystyrene microspheres with different sizes to construct a colloidal crystal with layered structures. Subsequently, the interstitial voids among the closely-packed microspheres are backfilled with Ni (via electrodeposition), followed by selective removal of the colloidal template. As a result, we are able to produce inverse opals with layered structures in which individual layers have different pore sizes. This gradient-pore inverse opaline structure, to our best knowledge, has not been reported in literatures. Our sequential electrophoresis route allows us to tailor-make gradient structures to accommodate specific applications. Material characterization including SEM, XRD, Hall effect, and BET analysis are performed and their results are discussed.
8:00 PM - PM04.09.21
Copper (II) ion-lysozyme Hybrid Microflowers and Their Antibacerial Effects
Jingyuan Xu 1 , Jing Li 1 , Leilei Tian 1
1 Materials Science and Technology, Southern University of Science and Technology, Shenzhen, Guagndong, China
Show AbstractOrganic–inorganic hybrid micromaterials, as the name shows, are the structure that the cores of organic materials are bound with inorganic microparticle components.
Apart from the sphere microparticles, the flower-like inorganic (metallic)-protein hybrid microstructure with the high surface area to volume ratio have piqued the interests of scientists because of their superior efficiency and enzyme stability.[1]
In our research, monodisperse protein (lysozyme)-copper ion microflowers particles with controlled diameters ranging from 10 μm to 50 μm have been prepared.
In this work, copper (II) ion-lysozyme hybrid microflowers were prepared with excellent antibacterial performance which could be applied to bacterial contamination detection and biological healthy test.
Our flower-like hybrid microstructure is a brand new idea for the organic-inorganic materials: the Cu2+-lysozyme hybrid microflowers were used for antibacterial applications, firstly due to their porous morphology easy for bacterium adsorption with large amount, and the mutual promotion of sterilization ability of the copper (II) ion and lysozyme themselves. The study of antibacterial efficiency could be promoted for about 14.5% exceeding of either of the raw materials, with the help of Escherichia coli and Staphylococcus aureus. This advance could probably be up to 20% with anticipation.
In order to maintain a moderate particle size distribution and achieve the controllable particle diameters, we adopted a simple synthesis method proposed by Ge et al[2], whose team used laccase, carbonic anhydrase and lipase as the organic compound with a pH 6.5 phosphate buffered saline (PBS). We extended his research for applying lysozyme with PBS of gradient pH from 6.0 to 6.9. Initially, we prepared a proper concentration of copper (II) sulfate and a series of concentration of lysozyme (PBS) solution. Then, we added Cu2+ solution carefully into the enzyme solution and mix them gently. After one day (24 hours) to three days (72 hours), a flower-like precipitate appeared. Through this strategy, we can achieve monodisperse microflowers with different size and denseness without any complicate operations and expensive facilities.
[1] Lee, S. W., Cheon, S. A., Kim, M. I., & Park, T. J. (2015). Organic–inorganic hybrid nanoflowers: types, characteristics, and future prospects. Journal of Nanobiotechnology, 13(1), 54.
[2] Ge, J., Lu, D., Liu, Z., & Liu, Z. (2009). Recent advances in nanostructured biocatalysts. Biochemical Engineering Journal, 44(1), 53-59.
8:00 PM - PM04.09.22
Transformation of Hexagonally Close-Packed Colloidal Monolayers into any Two-Dimensional Bravais Lattice—An All Solution-Based Process
Miriam Mauer 1 , Christian Stelling 1 , Bernd Kopera 1 , Fabian Nutz 1 , Matthias Karg 2 , Stephan Förster 3 , Markus Retsch 1
1 , University of Bayreuth, Bayreuth Germany, 2 , Heinrich-Heine Universität Düsseldorf, Düsseldorf Germany, 3 , Forschungszentrum Jülich GmbH, Jülich Germany
Show AbstractThe preparation of particle arrays on solid substrates is an essential step for the fabrication of functional surfaces and thin-film devices with applications in lithography, optics, photonics, high-density data storage and as adhesive/non-adhesive surfaces. Colloidal self-assembly represents an attractive and scalable route towards hexagonally close-packed particle arrays. Up to now, however, it is hardly possible to realize two-dimensional symmetries other than hexagonal packing. To significantly broaden the structural variability, the fabrication of non-close-packed and also non-hexagonal particle arrays is required. Here, we demonstrate how to fabricate non-close-packed particle arrays with symmetries of all possible Bravais lattices in a simple solution-based process. Our process starts with readily self-assembled, hexagonally close-packed monolayers, which are immobilized on an air/water interface. Upon transfer onto the target substrate, stretching along a specific crystallographic direction occurs. This yields non-close-packed structures with non-hexagonal symmetry. We demonstrate how to control the stretching factor by interfacial modification of the target substrate to access all possible Bravais lattices. Our process tremendously opens the possibilities provided by colloidal lithography, since it offers a versatile approach for batch or continuous fabrication of non-close packed particle arrays with per-determined symmetry.
8:00 PM - PM04.09.23
New Installation Method of Porous Membrane in a Microfluidic Channel
Seungyoon Han 1 2 3 , Dae Kun Hwang 1 2 3
1 , Ryerson University, Toronto, Ontario, Canada, 2 , Institute for Biomedical Engineering, Science and Technology (iBEST), Toronto, Ontario, Canada, 3 , Keen Research Center for Biomedical Science, Toronto, Ontario, Canada
Show AbstractMicrofluidic devices integrated with porous membranes have offered a simple but high throughput mass transport control for many microfluidic applications, such as single cell separation, sample analysis, and purification. In this study, we demonstrate a novel assembly process of porous membranes into microfluidic channels. This new approach to integrate porous membranes into microfluidic devices resolves many practical issues, such as leaking, normally observed in membraned-based microfluidics (multilayers) constructed by physical sealing. This approach also offer advantageous features, such as replacement of membranes, selection of membrane materials, and spatial configuration, over chemical sealing and in-situ fabrication. In our approach, we apply a magnetic field to install porous membranes, fabricated by using stop-flow lithography, into desire locations within PDMS microfluidic channels. Resulting PDMS microfluidic channels show no sign of leaking for their operation.
8:00 PM - PM04.09.24
Two-Dimensional Hierarchical Binary Superlattices of Functionalized 1D Nanoparticle/Cylindrical-Micellar System
Sung-Hwan Lim 1 , Taehoon Lee 1 , Younghoon Oh 2 , Theyencheri Narayanan 3 , Bong June Sung 2 , Sung-Min Choi 1
1 , Korea Advanced Institute of Science and Engineering, Daejeon Korea (the Republic of), 2 , Sogang University, Seoul Korea (the Republic of), 3 , ESRF, Grenoble France
Show AbstractSynthesis of binary or multicomponent superstructures of nanoparticle, which may provide new properties through synergetic coupling between different types of nanoparticles, has attracted great attentions for various potential applications as well as its own scientific merit.1 Exciting progress in the synthesis of binary superlattice has been intensively made with spherical nanoparticle with two different sizes, and various symmetries have been investigated by using an interplay of entropy and van der Waals, electrostatic, and other interactions. Very recently, a few different binary superlattices with the mixtures of spheres and nanorods and the mixtures of disks and nanorods have been also observed. However, systematic experimental studies on the mixtures of two different sizes of 1D nanoparticles to form highly ordered binary superlattices have been very rare.
Here, we investigated how 1D nanoparticles are self-assembled when they are mixed with a hexagonally ordered cylindrical-micellar system, depending on the diameter and number ratios between the 1D nanoparticles and cylindrical micelles.2,3 The 1D nanoparticles with different diameters (p-CnTVBs) were synthesized by in-situ polymerization of polymerizable cationic surfactants, n-alkyltrimethylammonium 4-vinylbenzoate (CnTVB, n is the number of carbon in alkyl chain), which form worm-like micelles in water. The non-ionic surfactant, penta(ethylene glycol) monododecyl ether (C12E5) in water were used to provide a pre-formed hexagonal system of micellar cylinder (4.3 nm in diameter). The diameter of the 1D nanoparticles was controlled by the alkyl chain length (n = 10, 12, 14, and 16). This allows us to vary the diameter of 1D nanoparticles (2.5 nm ~ 3.9 nm) systematically, and thus the diameter ratio between 1D nanoparticles and C12E5 cylinder is varied. When the p-CnTVB are added to the hexagonal phase of C12E5 cylinder (C12E5/water (45/55)), the binary mixtures of 1D nano-objects show two types of hierarchical superlattices, a hexagonal array of p-CnTVBs embedded in a honeycomb lattice or a kagome lattice of C12E5 cylinder, depending on the diameter and number ratios. The binary superlattices can be unidirectionally aligned with a large scale under oscillatory shear field. Theoretical free energy calculation showed that the formation of hierarchical superlattices of 1D nano-objects can be understood in terms of the free volume entropy-driven particle packing phenomena. The understanding obtained in this study may be applicable for designing highly ordered and highly aligned inorganic 1D nanoparticle binary superlattices of different symmetries and functionalities.
Reference
1. C. Yan et al., Chem. Soc. Rev. 46, 1483 (2017).
2. S.-H. Lim and S.-M. Choi et al., Angew. Chem. Int. Ed. 53, 12756 (2014).
3. S.-H. Lim and S.-M. Choi et al., Nat. Commun. 8, 360 (2017).
.
8:00 PM - PM04.09.25
Block Copolymers Self-Assembly to Ordered Nanomaterials
Aihua Chen 1
1 , Beihang University, Beijing China
Show AbstractBlock copolymers can produce numbers of microphase separated nanostructures with cylinder, lamellar, gyroid, sphere morphologies, etc., which are of wide scientific and technological interests. If any functional groups or properties are well assembled into the block copolymers, the functionality might act as a probe to elucidate the relationship of nanostructures with functionality, i.e., both nanostructures controlled by functionality and nanostructure-specific functionality. Self-assemblied amphilphlic block copolymers, either in solution or film, have been widely used as template to prepare versatile ordered materials. Since the first report of SBA-15 templated from EOPOEO triblock copolymers, organic and inorganic mesoporous materials with relatively larger pore size from block copolymers have been attracted numerous interesting in recent years [1, 2]. Moreover, the self-assembly of block copolymer thin films has also been widely studied for its potential utility in emerging nantechnologies such as nanolithography, nanotemplating, nanoporous membranes, and ultrahigh-density storage media. To control the self-assembly of BCP thin films, especially for highly ordered cylindrical domains perpendicular or parallel to substrates, is significant for the tailored application of block copolymer self-assembled thin films. In our group, we have studied to switch the alignment of PEO-b-PMA(Az) thin films trough a facile method, and mesoporous materials template from this BCP.
8:00 PM - PM04.09.26
Assembly of Novel Mineral-Based Luminescent Thin Films via Layer-by-Layer Self-Assemble Method
Meitang Liu 1 , Tianlei Wang 1 , Hongwen Ma 1
1 , China University of Geosciences (Beijing), Beijing China
Show AbstractLayered materials have attracted attentions to their excellent physicochemical properties and potential applications in future multifunctional devices, and the nanosheets of those have been used as building units of functional materials due to their intrinsic unique two-dimensional structure [1]. As the successful liquid exfoliation of layered materials and the fruitful assembly of the inorganic nanosheets with polyelectrolyte, quantum dots and so on, layer-by-layer self-assembly method (LBL method) have been masterly used to build layered and ordered functional materials [2, 3]. In our previous work, we selected exfoliated LDHs and MMT nanosheets with opposite charges to assemble a pseudo electronic microenvironment (PEM) via LBL method, which has not been declared in other literatures [4, 5]. When chromophores were intercalated into the PEM, the luminescent lifetimes are significantly prolonged. It is well-known that transition metal-bearing LDHs nanosheets can exhibit ferromagnetic effect (FE), so we introduced Co, Ni and Fe element etc. on the LDHs’ nanosheets. Surprisingly, the luminescent lifetimes based on ferromagnetic LDHs are significantly prolonged compared with that of the pristine chromophores, even much longer than those films without oppositely-charged and ferromagnetic architecture [6-8]. Therefore, it is highly expected that the PEM and FE formed by oppositely-charged and transition metal-bearing inorganic nanosheets have remarkable influence on obtaining better optical property, which suggest a new potential way to manipulate, control and develop the novel light-emitting materials and optical devices. In this presentation, we will give an explicit illustration on how to construct PEM and FE environment and introduce most of our newly developed interesting functional ultrathin films based on PEM and FE in detail.
References
[1]Parka, D.H., Hwang, S.J., Oh, J.M., Yang, J.H., Choy, J.H., Prog. Polym. Sci. 2013, 38, 1442.
[2]Nicolosi, V., Chhowalla, M., Kanatzidis, M.G., Strano, M.S., Coleman, J.N., Science 2013, 340, 1420.
[3]Wang, Q., O’Hare, D. Chem. Rev. 2011, 112, 4124.
[4]Wang T.L., Liu M.T., Ma H.W., Liu X.J., Fu Y., Hu K.R., RSC Adv. 2014, 4: 40748.
[5]Wang T.L., Liu M.T., Ma H.W., Appl. Sci-Basel 2016, 6: 272.
[6]Wang T.L., Liu M.T., Ma H.W., Fu Y., J. Nanosci. Nanotech. 2017, 17: 1434.
[7]Liu M.T.,Wang T.L., Ma H.W., Fu Y., Hu K.R., Guan C., Sci. Rep. UK 2014, 4: 7147.
[8]Liu M.T.,Wang T.L., Ma H.W., Fu Y., Hu K.R., Guan C., Mater. Lett. 2015, 153: 40.
8:00 PM - PM04.09.27
SU8 for Acoustofluidic Devices—Material Properties and Advanced Lithographic Techniques
Andreas Winkler 1 , Erik Angermann 1 , Citsabehsan Devendran 2 , Stefan Harazim 1 , Christine Henze 1 , Ingolf Mönch 1 , Adrian Neild 2 , Andrey Sotnikov 1 , Parsi Sreenivas Vijay 1 , Henning Turnow 1 , Robert Weser 1 , Hagen Schmidt 1 , Siegfried Menzel 1
1 , Leibniz Institute for Solid State and Material Research (IFW), Dresden Germany, 2 , Monash University, Clayton, Victoria, Australia
Show AbstractThe negative tone epoxy-based photoresist SU-8 is the material of choice for numerous microelectromechanical systems (MEMS) [1]. SU-8 exhibits high transparency in the visible light spectrum, low shrinking, excellent chemical resistance, and high mechanical and thermal stability. Furthermore, the possibilities of creating up to several millimeters thick SU-8 layers, structures with very high aspect ratios (up to 40), microchannels, reservoirs and pumps as well as biocompatible and even in vivo devices [2, 3] make this material interesting for (bio-)microfluidic as well as for upcoming acoustofluidic sensors and actuators including acoustic tweezers, particle sorters, mixers and aerosol generators.
In contrast to the state-of-the-art laboratory material Polydimethylsiloxane (PDMS), SU-8 is in principle suitable for parallel and cost-effective device manufacturing of acoustofluidic devices in a wafer-scale fashion with sub-micron resolution. While a few studies have already verified certain advantages of SU-8 in acoustofluidic applications [4-6], there is a current lack of knowledge on its acoustically-relevant properties in the microacoustic frequency range, including the elastic moduli, the density as well as the mode-dependent surface and bulk acoustic wave velocities and the associated attenuation coefficients. However, due to the complexity of the interaction of acoustic waves with solid and fluidic components, FEM simulations based on profound material properties are indispensable in order to predict and to tailor the behavior of acoustofluidic devices like sensors and actuators.
Using carefully designed test samples and improved measurement techniques, such as film density measurements via Archimedes’ principle, pulse-echo measurement, nanoindentation, laseracoustic velocity dispersion measurement, electrical network analysis and laser vibrometry, we determined the acoustically-relevant material properties of SU-8 films and structures. Furthermore, we demonstrate that the complex optical transmission / absorption properties of SU-8 in the deep-UV (DUV) wavelength region makes the choice of the exposure conditions crucial, while at the same time, they enable new simple techniques for the structuring of microchannels and -chambers. Based on an optical transmission measurement study of pre-baked SU-8 layers from 1 to 150 µm thickness in the wavelength range of 235 to 400 nm, we demonstrate a straightforward exposure technique for the creation of complex three dimensional enclosed microchannels within a single layer of SU-8.
1 Renaud, P. and A. Bertsch, Micromachines 6, 6, 790 (2015).
2 Huang, S.H., S.P. Lin et al., Sens. Act. A-Phys. 216, 257 (2014).
3 Nemani, K.V., K.L. Moodie et al., Mater. Sci. Eng. C-Mater. Biol. Appl. 33, 7, 4453 (2013).
4 Mu, C., Z. Zhang et al., Sens. Act. B - Chem. 215, 77 (2015).
5 Saiki, T. and Y. Utsumi, Elec. Comm. Japan 97, 1, 54 (2014).
6 Winkler, A., S. Harazim et al., Biomed. Microdev. 19, 1, 9 (2017).
8:00 PM - PM04.09.28
A Non-Destructive Micro-Sensor for In Situ Analysis of Ions in Plants
Stephanie Armas 1 , Parth Patel 1 , Jared Church 1 , Woo Hyoung Lee 1 , Swadeshmukul Santra 1 , Karin Chumbimuni-Torres 1
1 , University of Central Florida, Orlando, Florida, United States
Show AbstractHuanglongbing (HLB), more commonly known as citrus greening disease (CGD), is an insect-borne bacterial disease affecting citrus crops worldwide [1]. CGD symptoms can be visually seen throughout the plant, displaying yellowing veins, asymmetrical chlorosis and blotchy leaves, leading to underdeveloped fruit with green colored and stained seeds [1]. The mottling discoloration has been linked to zinc deficiency in the plant [3], thus monitoring varying concentrations of zinc in plants (in particular the phloem tissue) can be useful in early detection, monitoring disease progression and possibly therapy [2]. Here, the use of micro-ion selective electrodes (µ-ISEs), equipped with a µ-Ag/AgCl reference electrode will provide a non-destructive method for monitoring free zinc content in the phloem of plants, via a small incision. ISEs can provide the selectivity and sensitivity needed to detect micro- to nano-molar concentrations of zinc within a complex phloem sap matrix. Initially, a model ion, such as sodium, was used due its’ well established and well defined potential response. Here, two approaches were employed: mini- and micro-ISEs. First, conditioning protocols and membrane composition were studied and optimized in the mini-ISE (600 µm diameter) platform. The knowledge acquired was transferred to the µ-ISE (200µm (ISE+reference) sensor diameter) platform and thereby minimized optimization time in the microscale platform. Studies have yielded a near Nernstian slope of 51.86 mV response with a limit of detection (LOD) of 1.95 x10-6 M over a range of 1 x10-5 M to 0.6 M, for the sodium µ-ISE. The sodium electrode was then calibrated within the phloem/xylem sap in order to study matrix effects and determine the correlation of ΔE between water and sap. Lastly, sodium concentration was determined within three areas of leaves. Consequently, a zinc µ-ISE was also optimized in a similar fashion. The zinc µ-ISE shows a promising potential response of 34.5 mV with an LOD of 5.46x10-6 M over the linear range of 1 x10-5 M to 1 x10-2 M. Further studies will continue towards determining long stability of the sensors and reproducibility. For the first time a (µ-ISE) shows promise for application towards in situ plant analysis.
1. Hijaz, F. M.; Manthey, J. A.; Folimonova, S. Y.; Davis, C. L.; Jones, S. E.; Reyes-De-Corcuera, J. I. Plos One 2013,
2. Batool, A.; Iftikhar, Y.; Mughal, S. M.; Khan, M. M.; Jaskani, M. J.; Abbas, M.; Khan, I. A. Horticultural Science 2007, 34, 159-U153.
8:00 PM - PM04.09.29
Monolayer Printed Thermochrmic with a Fast Color-Switching
Hyesoo Kim 1 , Sungjun Cho 1 , Gwangmook Kim 1 , Sooun Lee 1 , Wooyoung Shim 1
1 , Yonsei University, Seoul Korea (the Republic of)
Show AbstractThe ability to induce the coloration for display with molecular inks has stimulated intense research efforts to use chromic as an ink for reflective-type visual information on surfaces. These techniuqes rely on spcific chromic inks to enable the change of colors under external stimuli: (i) mechanochromic ink requires mechanical forces such as rubbing, crushing, pressing, shearing, and smearing; (ii) elecctrochromic ink requires the electric field; and (iii) thermochromic requirs heat. A challenge common to chromic-enabled display is to change the color with fast color-switching time despite the mass-dependent nature of chromic inks. Thermochromic inks need to be effectively coupled with external heat to induce the coloration, which generally involves in a slow heat transfer processes that are not suitable for potential display applications. Here we show a method of molecular printing of thermochromic ink of low heat capacity, enabling an unprecedented fast color-switching without optoelectronic elements. Molecular printed-ink is patterned on fabricated microheaters that induce transient local heat generation, leading to facilitating the rate of local heating and cooling processes. Depending on the density of thermochromic ink, i.e., number of microcapsuled dye in the form of the monolayer leading to low heat capacity, the chroma of the patterned ink can be increased. Using this technique we can print the thermochromic ink with an area of centimeter scale, CMYK colors, and a color-switching rate of 20 - 500 ms, which is integrated into thermochromic device prototype for potential display applications.
8:00 PM - PM04.09.30
A Study of Parameters on Jet Flow Rate in Near-Field Electrospinning for Precise Nanofiber Patterning
Dongwoon Shin 1 , Jong-Hyun Kim 1 , Jiyoung Chang 1
1 , University of Utah, Salt Lake City, Utah, United States
Show AbstractElectrospinning is a technique to generate nanofibers out of polymer solution in an electric field, and it has many applications in the fiber-based sensors, filtrations, tissue scaffold implants, and batteries. Despite electrospinning is an effective method to produce nanofiber, obtaining the desired pattern is challenging especially in microscale due to Coulomb repulsive force between fibers and lack of jet flow rate control. In particular, measurement of the jet flow rate was performed in far-field electrospinning, but no measurement or control of jet flow rate in near-field electrospinning with a tip-to-collector distance of 1 mm or less was reported. This paper investigates the major parameters that affect the jet flow rate in electrospinning under working distance between 0.5mm to 1mm for the first time. Three parameters were set to identify the major factors affecting the jet flow rate at intervals of less than 1 mm, which are an electric field, voltage, and working distance. Three different setups were tested such as decreased electric field by decreasing voltage with fixed distance, increased electric field by reducing distance with fixed voltage, and constant electric field by decreasing the other two factors proportionally. All experiments were conducted with the working distance between 0.5mm and 1.0mm, the voltage between 500V and 1000V. In order to predict the jet speed, we used the relation between the shape of the fibers being deposited on the collector and the velocity of the stage. The tendency of the spun-fiber getting straight was noticed in the first and the second experiment. Also, it was recognized that there was a certain condition that the spun-fiber was formed straight when the jet speed was equal to the speed of the stage. The jet diameter became smaller in the first test while it became larger in the second. In the constant electric field, the spun-fiber turned out to be straight and thinner from coiled and thicker as both the applied voltage and the working distance decreased. To sum up, the control of the jet flow rate is the key for slow jet speed and small diameter of the jet to have a precise nanofiber pattern. Through the experiment, it was verified that the jet speed and the diameter of the jet were dominated by the applied voltage the most. Based on the result, another experiment of electrospinning at 400V and 0.5mm was performed to accomplish the desired patterning in the stage speed of 5, 10, and 15mm/s. As a result, the desired image was patterned with straight nanofiber at 15mm/s in the area of 500µm by 500µm. Achieving more complicated design at a lower voltage in a smaller area will be future work. This paper will present the effect of other parameters, including molecular weight of polymer and polymer concentration, to the jet flow rate. This study will also provide a theoretical foundation for realizing polymer based microscale patterning and 3D printing in the future.
8:00 PM - PM04.09.31
Printed Paper Biosenors Embedded with Functional Nanoparticle Assembly as Sensing Interfaces for Human Performace Monitoring
Shan Yan 1 , Cameron Ghazvini 1 , Chirag Soni 1 , Ross Hernandez 1 , Jack Lombardi 2 , Jin Luo 1 , Mark D. Poliks 2 , Benjamin Hsiao 3 , Chuan-Jian Zhong 1
1 Chemistry, SUNY-Binghamton, Binghamton, New York, United States, 2 Science and Industrial Engineering, SUNY-Binghamton, Binghamton, New York, United States, 3 Chemistry, Stony Brook University, Stony Brook, New York, United States
Show AbstractPaper based sensors offer an intriguing alternative to conventional sensors with attractive features such as low cost and high flexibility, disposability, and permeability. However, a major drawback is that standard microfabrication techniques, such as physical vapor deposition and photolithography, cannot be used in paper sensor fabrication because of the high temperature requirement. This paper describes a study of paper-based sensors fabricated at room temperature using aerosol jet printing as a high-resolution additive process for the deposition of nanoink materials on paper substrates. Interdigitated microelectrodes were printed on multi-layered fibrous membrane-type paper in a one-step process using conductive metal nanoparticles and carbon nanomaterials. With additively fabricated microelectrodes on the paper, functionalized metal and alloy nanoparticle (e.g., Au, AuCu, etc.) thin films are deposited as sensing interfaces. Testing of the sensors in human performance monitoring has demonstrated an enhancement in sensitivity in comparison with sensors fabricated with conventional substrates, which significant implications for design and manufacturing of a fully-printable and highly-sensitive human performance monitor coupled to flexible electronics towards wearable and wireless applications.
8:00 PM - PM04.09.32
Preparation of α-alumina Powder and Binder for 3D Printer
Ryohei Hamano 1 , Toshiyuki Ikoma 1
1 , Tokyo Institute of Technology, Tokyo Japan
Show AbstractAlpha-alumina is a ceramic with excellent chemical stability, mechanical properties, high melting point, and insulating property; however, it shows poor workability due to its low fracture toughness. There are a lot of molding processes for α-alumina, such as a press molding and an extruding molding. 3D printing is rapidly growing technology to make complex and precious moldings. Ceramics with self-hydration hardening properties, gypsum and tricalcium phosphate, have been applied for 3D printers. However, there are only a few descriptions on 3D printings for α-alumina due to no hydration hardening property. To achieve α-alumina moldings with the ink-jet powder laminating method, powder fluidity of α-alumina with different particle sizes and binders for bonding the powders should be investigated. The purposes of this study are to elucidate influences 1) of particle size distribution (PSD) of α-alumina powders to their powder fluidity, 2) of binders to bond α-alumina powder firmly, and 3) of PSD and binders to mechanical strength of moldings and sintered bodies.
Powder fluidity was evaluated with Hausner ratio for the powders with different PSD, in which the weight ratios of A20, A3 and A04 particles with average particle diameters of 20.1 μm, 3.4 μm, and 0.4 μm were changed. The ratio, generally depends on bridging of particles, can be calculated from their packing and tap densities. Zeta-potential of each particle was measured with a microscope electrophoresis method. Polyallylamine (PAA) as a cationic polymer or polyvinyl alcohol (PVA) as a nonionic polymer was used as a binder to bond the powders. The cylindrical rubber molds with Φ 5 × 3 mm in size were prepared and the powders were just put in. The binders were dropped onto the powders molded and dried at room temperature for 1 night to judge the formation of moldings. Finally, the powders adjusted and binders were employed for a 3D printer. The printed moldings were sintered at 1500°C for 5 h. The compressive strength of the moldings and the sintered bodies was measured.
Hausner ratio of the powders with the weight ratio of A20: A3: A04 at 63: 27: 10 (X) and 56: 24: 20 (Y) were 1.19 and 1.23, correspondingly. Zeta-potentials of α-alumina particles showed bimodal peaks at +30.0 mV and -23.2 mV for A3, and that showed single peak at -9.1 mV for A04. By using rubber molds, the drop of PAA binder on both the powders can make moldings; however, the PVA addition cannot form moldings. This indicates that the charge of binders is strongly affected to the molding properties of α-alumina. The printed moldings by using the powder of X had the relative packing density of 40% in the 3D printer; however, the powder of Y cannot form any powder beds. The compressive strength of the printed moldings was 8.2 kPa, and that of sintered bodies with relative density of 40% was increased at 3.6 MPa. The powder with X showed near-net zero shrinkage even after sintering at 1500°C.
8:00 PM - PM04.09.33
Facile Diatom Frustule Monolayer Assembly Method
Aobo Li 1 , Mahetem Moges 2 , Javier Morales 3 , Amy Saccoccio 4 , Stephan Anderson 5 , Xin Zhang 1
1 , Boston University, Boston, Massachusetts, United States, 2 , Georgia Institute of Technology, Atlanta, Georgia, United States, 3 , Interamerican University, San Germán, Puerto Rico, United States, 4 , Randolph Community Middle School, Randolph, Massachusetts, United States, 5 , Boston University Medical Center, Boston, Massachusetts, United States
Show AbstractDiatoms are unicellular microalgae which are ubiquitous in aquatic environments and remarkably diverse. The silica exoskeletons represent biologically evolved micro- and nanostructured materials. Typically, diatom frustules contain dense arrays of micro and nano pores, which result in large surface areas. Diatoms represent promising candidates for developing a range of biologically-enabled technologies, given their highly organized, intricate micro- and nanoscale morphology. For example, they have been leveraged as biological sensors. Several studies have been reported in which single diatom frustules serve as sensitive components in innovative sensors. Since diatom frustules are naturally compatible with silica surface modification techniques, these biological materials have been modified in this fashion and applied to a variety of bio-sensing applications.
The advanced properties of diatoms have typically been studied on the scale of the single diatom frustule (for example, in sensing) or on the scale of arrays of randomly oriented diatom frustules. In diatom-based sensing and optical devices, individual diatom manipulation is required for device fabrication, which has greatly limited their application in batch fabrication. Therefore, effective methods for arranging diatoms into large area, uniformly oriented monolayers and/or arrays will also be explored. With the aid of such techniques, in combination with the aforementioned material synthesis/modification techniques, it will be possible to batch manipulate frustules for a variety of fabrication purposes.
In this study, we present a facile method for assembling diatom frustule monolayers. Frustules from Coscinodiscus sp. (C. sp.) diatoms were cleaned with concentrated sulfuric acid under 60 °C for 40 min, followed by repeated dilution and settling. A silicon wafer was used as the substrate for the assembling. It was first treated with O2 plasma before being submerged under water. C. sp. suspension was then dropped in the water for settling. Water beam with a flow rate of 10 ml/min and a diameter of ~500 μm was then injected under water to flush the frustules gently to push them together.
We found that diatom frustules tend to stick to hydrophilic silicon substrate surfaces under water, and move along the surface when exposed to jets of water. With fine control of the water jets, compact diatom frustule monolayers may be readily formed, rendering the method to be the most effective method towards making compact frustule monolayers. We hypothesize that with different diatom sides (concave side or convex side) contacting the substrate, frustules will exhibit varying kinetics of distribution along the surface, which may serve to differentiate the two types of frustules spatially on the substrate. Such technique has the potential to serve as the method for both assembling and orientation control of diatom frustule in future sensor developments.
8:00 PM - PM04.09.35
Aerosol-Jet Printing of Compliant Ball Grid Array Pads
Shayandev Sinha 1 , Jesse Singer 2 , Daniel Hines 2 , Abhijit Dasgupta 1 , Siddhartha Das 1
1 , University of Maryland, College Park, Maryland, United States, 2 , Laboratory for Physical Sciences, College Park, Maryland, United States
Show AbstractBall Grid Arrays (BGA) are typically solder bumped bonding pads which, after a reflow process, establish a mechanical and electrical connection between a surface mounted (SMT) electrical component and a printed circuit board (PCB). High-temperature processing is required for many of these reflow processes, leading to thermal shock which can damage some electrical components. Additionally, for the production of flexible circuits on a polymer substrate, there is a requirement for lower temperature processing capabilities (around 150 °C) and for reducing strain resulting from mechanical stresses that can build up during the reflow process. Additive manufacturing techniques provide an alternative methodology that can be used to fabricate a direct replacement for standard, solder bumped BGAs. We have developed aerosol-jet (AJ) printing methods to fabricate a polymer bumped BGA. As a demonstration of the process, a test chip was first polymer bumped using an AJ printed, ultra-violet (UV) curable polymer ink and then subsequently coated with an AJ printed silver nanoparticle-laden ink in order to establish a conducting layer printed over the polymer bump. The structure for the polymer bumps was achieved by printing the polymer ink using a specific toolpath coupled with in-situ UV curing of the polymer. This process provided good control over the shape, resulting in well-formed bumps on the order of 150 um in diameter by 200 um tall. A detailed discussion of the related AJ printing methods will be presented. Characterization of overspray in AJ printing with respect to controlled printing of structures will also be discussed.
Symposium Organizers
Takafumi Fukushima, Tohoku University
Kanchan Ghosal, X-celeprint Inc.
Gregory Whiting, University of Colorado Boulder
Hongbin Yu, Arizona State University
PM04.10: Nano Manufacturing
Session Chairs
Thursday AM, November 30, 2017
Sheraton, 3rd Floor, Fairfax A
8:30 AM - *PM04.10.01
An Assembly Tool for Manufacturing Macro Systems from Micro-Scale Objects
Julie Bert 1 , Jeng Ping Lu 1 , Lara Crawford 1 , Sourobh Raychaudhuri 1 , Anne Plochowietz 1 , Bradley Rupp 1 , Yunda Wang 1 , Jamie Kalb 1 , George Gibson 2 , Gregory Burton 1 , René Lujan 1 , Qian Wang 1 , Yu Wang 1 , Ion Matei 1 , Patrick Maeda 1 , Daniel Davies 1 , David Biegelsen 1 , Eugene Chow 1
1 , PARC, A Xerox Company, Palo Alto, California, United States, 2 Xerox Research Center, Xerox Corporation, Webster, New York, United States
Show AbstractWell established top down manufacturing techniques exist for assembling objects with high positional accuracy on millimeter length scales. Additionally, the significant research focus on nanotechnology over the past few decades has produced reliable bottoms up self-assembly at the nanoscale. However, there remains a gap in the ability to manufacture assemblies comprised of micrometer scale components. This limitation also constrains the utility of nano-scale assemblies that could provide unique functionality when incorporated into larger ordered heterogeneous structures. To address this gap we present a micro-scale digital assembly system capable of placing objects as small as 10 um with 1 um accuracy. Our assembly system consists of an optically driven electrostatic actuator array for positioning the micro-objects in two dimensions. The objects are suspended in a dielectric fluid on the array, and the array electrodes are used to dynamically manipulate the electric potential landscape to control their position and orientation. This reusable assembly array is integrated with a transfer system to move assembled patterns to a final substrate without loss of positional fidelity in order to enable functional use of the assemblies. This talk will describe the system architecture of our micro-assembler and present our recent assembly results including quickly ordering large numbers of particles with very high throughput, using computer vision to assemble highly accurate patterns, and transferring an assembled pattern to a final substrate with high fidelity.
9:00 AM - *PM04.10.02
Simultaneous and Independent Acoustic Manipulation and Assembly of Multiple Miniature Objects Using a Single Actuator
Quan Zhou 1
1 , Aalto University, Espoo Finland
Show AbstractSimultaneous and independent manipulation and assembly of multiple objects is a grand challenge in micromanipulation and microassembly. So far, the most promising solution is optical tweezer, which requires the objects under manipulation being transparent. Limited successes have also been achieved in magnetic manipulation by exploiting the differences in object properties. Here, we report an acoustic technique that has little restriction on the properties of the objects. Our system is extremely simple, consisting of a single piezo actuator mounted at the center of a vibrating plated. We can achieve simultaneous and independent manipulation and assembly of multiple particles on the plate by employing spatially highly nonlinear excitation fields. We model the nonlinear excitation field using particle tracking velocimetry for a large set of frequencies. Based on the model, we can achieve simultaneous manipulation and assembly of multiple particles in tasks such as trajectory following, particle assembling, pattern transformation, and droplet merging. Despite the reported acoustic manipulation is achieved on a vibration plate, the method can be extended to other energy fields as soon as they are spatially highly nonlinear and such nonlinearity can be excited.
9:30 AM - PM04.10.03
Additive Manufacturing of Ingestible Gastroretentive Biomedical Electronics
Yong Lin Kong 1 , Robert Langer 1 , Giovanni Traverso 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractIngestible electronics provides an attractive means of embedding active biomedical functionalities into the human body without requiring invasive surgical procedures. In particular, the gastric environment offers a immune privileged site in the human body that can tolerate the introduction of foreign devices without eliciting life-threatening immune responses. Yet, the long-term retention of such devices is challenging due to the mechanically and chemically hostile dynamic gastric environment. Further, constrained by the limitation of conventional manufacturing, current ingestible gastric electronics lack the ability to be retained in the stomach beyond a day. Here we demonstrate an approach to prolong the retention of gastric electronics to weeks via multi-material three-dimensional design and fabrication. The multi-scale additive manufacturing approach enabled the seamless incorporation of active trigger-able modules such as drug release reservoirs. Ultimately, the ability to create a personalized multi-functional ingestible gastroretentive electronics could enable a surgical-free integration of wireless medical devices with the human body.
9:45 AM - PM04.10.04
Thermocapillary Multidewetting of Thin Films
Arielle Marie Gamboa 1 , Michael Nitzsche 1 , Valeria Saro-Cortes 1 , Tianxing Ma 1 , Lin Lei 1 , Jonathan Singer 1
1 Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States
Show AbstractThermocapillary dewetting of liquids and molten films has recently emerged as a viable alternative to conventional microprocessing methods. As this thermal gradient-induced mechanism is universal, it can be applied to any material. This work explores the sequential dewetting of materials with varying melting points, including polymers and metals, to create aligned morphologies. The variation in melting point allows for the dewetting of single layers at a time or mobility-limited simultaneous dewetting. As a result, a variety of multimaterial structures can be produced with built-in alignment, such as arrays of concentric circles, lines with periodic segmentation, or islands on holes. This approach employs photothermal methods to induce the necessary thermal gradient, manipulating several variables in order to influence the consequent structures. Adjusting laser power and light intensity allows for the control of temperature for selective dewetting of films; altering beam size and exposure time affects the extent of dewetting in terms of diameter size; overlap effects and simultaneous dewetting can result in complex architectures. This controlled writing of patterns also presents a technique to create both masks at low temperatures for conductive multilayers as well as templates for electrospray deposition.
PM04.11: Flexible Assembly
Session Chairs
Thursday PM, November 30, 2017
Sheraton, 3rd Floor, Fairfax A
10:30 AM - PM04.11.01
Digitally Printed Flexible Organic Photodiodes with Self-Organized Electrodes
Ralph Eckstein 1 2 , Noah Strobel 1 2 , Tobias Rödlmeier 1 2 , Uli Lemmer 1 2 , Gerardo Hernandez-Sosa 1 2
1 , Karlsruhe Inst of Technology, Karlsruhe Germany, 2 , InnovationLab, Heidelberg Germany
Show AbstractOrganic semiconductors offer promising and unique properties towards light-sensing applications e.g. tunable absorption spectra, solution processability, mechanical flexibility and high internal quantum efficiencies. For that reason, optical sensors using these materials fabricated by industrial relevant printing techniques will become more and more relevant for many applications in e.g. sensing in wearables and medical diagnostics, environmental monitoring, or automotive industry. In this work we present highly efficient multi-layer organic photodiodes based on the polymer-fullerene blend PTB7:PC70BM, an AZO electron transport layer, and PEDOT:PSS electrodes, which were entirely aerosol jet printed on flexible PET substrates.[1] Furthermore, we demonstrate the fabrication of photodiode arrays throug a direct-printed patterning technique based on surface energy contrast which enables teh self organization of the functional inks. This technique allows for a reproducible deposition of multilayer devices with high registration accuracy and feature sizes down to a few micrometers.[2] We present a comprehensive electrical and optical characterization of the printed layers and devices in dependency of the active layer thicknesses, surface topography and transparency. The devices exhibited specific detectivities of >1E12 Jones over a broad wavelength range (400-750 nm) and maximum responsivities of 0.25 A/W.
[1] R. Eckstein, T. Rödlmeier, T. Glaser, R. Mauer, S. Valouch, U. Lemmer, G. Hernandez-Sosa.
Advanced Electronic Materials, 1,1500101 (2015)
[2] R. Eckstein, M. Alt, T. Rödlmeier, P. Scharfer, U. Lemmer, G. Hernandez-Sosa
Advanced Materials, 28, 7708 (2016)
10:45 AM - PM04.11.02
Self-Aligned Strategy for Printed Electronics
Woo Hyun 1 , Lorraine Francis 1 , C. Daniel Frisbie 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show AbstractPrinted electronics is an emerging field for additive manufacturing of electronic devices with low cost and minimal material waste for a wide range of application areas including displays, distributed sensing, smart packaging, and energy management. Moreover, its compatibility with roll-to-roll production formats and flexible substrates is desirable for high-throughput manufacturing of flexible electronics. Despite the promise, however, the roll-to-roll production of printed electronics is quite challenging due to web movement hindering accurate ink registration and high-fidelity printing. To address this challenge, we have developed a self-aligned printing strategy compatible with roll-to-roll manufacturing by utilizing capillary action of liquid inks on microstructured surfaces. In the process that we term Self-aligned Capillarity-Assisted Lithography for Electronics (SCALE), microstructured ink reservoirs and capillary channels are imprinted on plastic substrates and filled by inkjet printing of functional materials into the reservoirs. The liquid inks move under capillary flow into the adjoining channels, allowing high-resolution patterning and self-alignment of functional materials to build electronic devices with generous printing tolerance. In this talk, I will show fabrication of key building blocks (e.g. transistor, resistor, and capacitor) for electronic circuits using the SCALE process on plastics, suggesting a reliable, effective, and versatile platform to realize high-throughput manufacturing of printed and flexible electronics.
11:00 AM - PM04.11.03
Fully Ink-Jet Printed, Self-Aligned Resistors on Flexible Substrates with Resistance from 10 to 106 Ω and Their Applications in Printed RC Filters
Motao Cao 1 , Krystopher Jochem 1 , Lorraine Francis 1 , C. Daniel Frisbie 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show AbstractInkjet-printing is a promising way to fabricate electronic devices on plastic substrates at low cost. However, its further application to high throughput roll-to-roll processing is limited by both resolution and layer-to-layer alignment for multilayered devices. To solve this problem, a novel self-aligned printing method has been developed, which involves imprinting an open network of reservoirs, capillaries and device structures on a flexible substrate, inkjet printing electronically functional inks into the reservoirs and using capillarity to fill features to create electronic components. Fabrication of various of transistors, capacitors and resistors has been demonstrated. This presentation focuses on printed resistors, one of the major building blocks for realizing printed flexible electronics. The challenge of fabricating resistors using this self-aligned strategy lies in precisely control the resistance value in a large range without significantly changing the size of the devices. In this work, we achieved fully inkjet-printed, self-aligned resistors with resistance values ranging over six orders of magnitudes while keeping the overall size of the device constant. Poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) was used as the resistive material, and silver was used for the electrodes. The thickness uniformity of the PEDOT: PSS films in the circular reservoirs of the device structure was improved through the addition of isopropyl alcohol to lower the surface tension of the inks. We then altered the resistance by changing the geometry of the electrodes as well as modifying the ink with ethylene glycol or another type of PEDOT: PSS ink with a higher resistivity. Fully printed low pass RC filters with tunable cut-off frequency were also fabricated to demonstrate the AC behaviors of the resistors in circuits. The printing method has a good repeatability and is compatible with low cost, high throughput roll-to-roll printing.
11:15 AM - PM04.11.04
Flexible Light-Emitting and Light-Sensing Devices Fabricated with Nanogap Electrodes via Adhesion Lithography
Dimitra Georgiadou 1 , Gwenhivir Wyatt-Moon 1 , Yen-Hung Lin 2 , Alina Zoladek-Lemanczyk 3 , James Semple 1 , Suhas Mahesh 2 , Fernando Castro 3 , Henry Snaith 2 , Thomas Anthopoulos 1 4
1 Department of Physics, Imperial College London, London United Kingdom, 2 Department of Physics, University of Oxford, Oxford United Kingdom, 3 , National Physical Laboratory, Teddington United Kingdom, 4 Materials Science & Engineering, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal Saudi Arabia
Show AbstractNanogap electrodes have received significant attention during the last decades and several nanotechnology approaches have been proposed for the fabrication of co-planar electrodes with a separation reaching atomic scale resolution. However, no existing method is able to upscale the manufacturing of such nanogap electrodes at a low cost without compromising the quality and reliability of these nanostructures.
To address this challenge, our group has recently introduced adhesion lithography (a-lith), an innovative technique that can be used for the patterning of sub-15 nm nanogaps between symmetric or asymmetric metal electrodes [1]. We have shown that a-lith is a high throughput, simple and facile technique that can be applied on arbitrary substrate material types and sizes, while it can be performed in ambient conditions, bearing no toxicity issues and requiring relatively low equipment cost. The fact that dissimilar metals can be patterned this way has allowed the fabrication of nanoscale devices such as radiofrequency Schottky diodes [2], semiconductor-free non-volatile memory [3] and other electronic devices.
Herein we demonstrate nanoscale optoelectronic devices, namely organic light-emitting nanodiodes (nano-OLEDs) and nanoscale photodetectors (n-PDs), fabricated with a-lith patterned nanogap electrodes. In nano-OLEDs, the light is emitted from a narrow active region that is defined by the nanogap geometry and specifically the electrodes thickness and the nanogap length/width. It will be shown how the unique large aspect ratio geometry leads to high performance polymer light-emitting devices that can operate in both continuous DC and pulsed AC mode, the latter leading to better heat dissipation and longer operational stability.
In the case of n-PDs, the narrow channel length is expected to efficiently dissociate electron–hole pairs and subsequently sweep them to the electrodes before they recombine. Our group has already reported preliminary results on n-PDs using P3HT:PCBM blends and CuSCN UV-sensitive photodiodes. On that basis we exploit further the versatility offered by these nanoscale structures upon combining the a-lith electrodes with solution-processed perovskite materials to engineer highly efficient low operation voltage (<0.5 V), high on/off ratio (>100) and fast photoresponse (<1 ms) photodiodes.
The successful demonstration of fully functional optoelectronic nano-scale devices on plastic substrates of arbitrary size renders this exemplary manufacturing platform unique within the field of printed and plastic electronics. Moreover, intelligent materials selection and engineering pave the way to the next generation flexible light-emitting and light-sensing devices that can be tailored to match the requirements posed by the specific target application.
[1] D. J. Beesley et al., Nature Communications 5, 3933 (2014)
[2] J. Semple et al., Small 12, 1993 (2016)
[3] J. Semple et al., IEEE Transactions on Electron Devices 64, 1973 (2017)
11:30 AM - PM04.11.05
Assembling of Thin Form Electronic Devices on Bioresorbable Substrates
Haokai Yang 1 , Wenwen Xu 1 , Todd Houghton 1 , Hanqing Jiang 1 , Hongbin Yu 1
1 , Arizona State University, Tempe, Arizona, United States
Show AbstractAs the advanced microelectronics technology continues to progress, medical devices, in particular implantable biomedical devices have seen increasing use in medical practices. Traditionally, such medical implantable devices are made of rigid materials that will be left inside the patients’ body for prolonged time even after the devices have ceased to function, and could leave the patients feel discomfort and even affect their motion and daily life. It is therefore crucial to develop of new kind of medical implants that are bioresorbable or biodegradable inside the patients’ body after desired amount of time. Among many challenges are the integration of functional devices with bioresorbable substrates. In this work, we demonstrate the fabrication of very thin form of the electronics devices, including transistors and their subsequent assembling and integration onto bioresorbable substrate materials, and the testing of these devices under chemical conditions that resemble biological environment. Electronic devices are fabricated on silicon-on-insulator (SOI) substrates, thereby these devices can be released from the bulk substrate to facilitate subsequent transfer process onto flexible and bioresorbable substrates. Many substrate materials were tested, such as gelatin along with other biocompatible materials. Further testing after assembling of these microscopic devices with close to submicron thickness were testing in biological relevant chemical environment.
11:45 AM - PM04.11.06
Foldable Paper Electronics by Direct-Write Laser Patterning
Xining Zang 1 , Yao Chu 1 , Buxuan Li 1 , Minsong Wei 1 , Liwei Lin 1
1 , University of California, Berkeley, Berkeley, California, United States
Show AbstractIn the past decade, great amount of attention has been attracted in clean energy and clean techniques. Recyclability and disposability graduate become an essential evaluation of materials and devices. Wasted paper have been demonstrated the potential to be used in disposable electronics, which has inspired many researchers to work on paper based electronics. So far, paper based energy generator, paper based energy storage devices including battery and supercapacitors, paper platform sensor and actuator, low cost on-paper diagnosis and paper based microfluidics have all been investigated with fruitful results. Most of former works are based on the additional manufacturing by depositing functional materials on paper such as the wax printing, evaporation, and lithography process.
In this paper, we demonstrated for the first time converting non-conductive paper to conductor directly by IR/UV laser in which process integrated circuit is patterned. Anti-intuitively, ablated paper did not burn into ashes but converted to highly conductive Molybdenum (Mo) carbide (Mo3C2) grafted graphene paper (MG-paper) due to the rinsing gelatin mediated Mo ion ink. Besides the inherent porosity from paper fibers, laser generated a lot more nanoscale pores due to the high local temperature generated by focus laser beam. Such hierarchical nano-to-micro scale porous MG-paper, showed pressure and gas sensing ability with the graphene base and carbide charge transfer promoter. Strengthened paper fabrics provided resilience to folding induced deformation, where the conductivity of converted paper showed less than 30% decay after 800 cycles. Direct patterned electret generator, van-shape foldable generator with promoted current density, interdigit supercapacitor were demonstrated successfully. Foldable circuits could be patterned by laser and assembled by Origami mechanism, which brings the promise of higher dimension electronic circuits.
PM04.12: 3D Assembly
Session Chairs
Thursday PM, November 30, 2017
Sheraton, 3rd Floor, Fairfax A
1:30 PM - *PM04.12.01
Three-Dimensional Micro and Nanoassembly by Self-Folding
David Gracias 1
1 Department of Chemical and Biomolecular Engineering; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States
Show AbstractThree dimensional high-throughput assembly of functional, multi-material microstructures remains a major challenge for engineering. While high-throughput photo and nanoimprint lithography and serial approaches such as e-beam / ion beam lithography have revolutionized science and engineering with their extreme precision and reproducibility, they represent inherently 2D layered patterning methodologies. More recently, 3D printing has emerged as a strategy to create functional micro and sub-mm structures but have limited material, throughput and resolution capability. Here, the assembly of 3D patterned structures by curving, bending and folding using mismatch strain engineering, surface tension and differential swelling will be discussed. The methods leverage the afore mentioned patterning techniques but also include the added step of differential patterning of engineered strain within the planar films so that 3D microstructures with multi-materials and high resolution patterned can be assembled into curved and 3D structures a highly parallel manner. In addition a discussion of materials and self-folding processes, several enabled applications in electronics (e.g. assembly of 3D interconnected computationl devices, 3-axis sensors), optics (e.g. metasurfaces and metamaterials) and biomedical engineering (e.g. microsurgical tools and curved tissue models) will be discussed.
2:00 PM - *PM04.12.02
Tensile Fatigue Testing System of Micro Specimens Using a Micro Manipulator
Kensuke Tsuchiya 1
1 , The University of Tokyo, Tokyo Japan
Show AbstractWe developed a micro-scale tensile fatigue test system, which can test specimens fabricated from bulk materials.
The system consists of a probe attached to a micro-manipulator, a micro-manipulator with a load sensor for accurate initial positioning and applying tensile stress, and a scanning electron microscope for observation.
This paper reports the design of the system and the result of tensile tests and tensile fatigue tests on the specimens which are made of coarse-grained magnesium alloy AZ31 whose crystallographic structures ware analysed by EBSD method.
The results indicate the following conclusions;
1. The developed system can apply accurate tensile stress in intended amplitude, frequency and number of cycles, and observation of specimens enables to determine whether the tensile stress is applied accurately.
2. Tensile strength and tensile fatigue strength of micro-scale specimens are much larger than that of macro-scale specimens.
3. The tensile strength is dependent on the crystal orientations.
According to these facts, the developed micro-scale tensile fatigue test system enables to examine the tensile strength and fatigue limit of micro-scale specimens.
2:30 PM - PM04.12.03
3D Self-Assembly by Remotely Transmitted Microwave Energy for Enhanced Manipulative Capability
Chao Liu 1 , Joseph Schauff 1 , Daeha Joung 1 , Jeong-Hyun Cho 1
1 , University of Minnesota, Minneapolis, Minnesota, United States
Show AbstractA novel self-assembly technique has been developed to control the self-assembly process remotely using a microwave energy. Three-dimensional (3D) micro-scale structures can be easily created using such assembly technique by integrating a nanometer thick metal (chromium, Cr) thin film in the micro-scale structure. The Cr thin film absorbs microwave energy and generates heat due to eddy current and Ohmic heating. The generated heat energy melts the polymeric hinges and triggers self-assembly process. Since the assembly process is controlled by a remotely located microwave energy source, direct contact between a heat source and the micro-scale structures is not required, leading to an enhanced manipulative capability of the 3D assembly process. By locating Cr thin films with different thicknesses adjacent to the hinges, multiple folding configurations can also be achieved simultaneously on a single micro-scale structure. The achievement of multiple folding angles in a single structure is crucial for building complex structures for various applications like complex micro machines and micro robots. Taking advantage of the highly manipulative property of the remote-controlled self-assembly, such micro-scale machines can be easily sent to restricted environments or even human bodies and then assembled into their functional forms to complete diverse tasks.
2:45 PM - PM04.12.04
Understanding the Rolling Behavior of a Cylindrical Micro-Object in Adhesional Contact for Mechanical and Adhesional Micro-Manipulation
Shigeki Saito 1 , Ming Dao 2
1 , Tokyo Institute of Technology, Tokyo Japan, 2 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractUnderstanding the rolling behavior of a cylindrical micro-object is critical for establishing the proper techniques of micromanipulation and micro-assembly by mechanical means. In this study, the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface is presented using a combined theoretical/computational approach. Closed-form dimensionless expressions for the critical rolling moment, the initial rolling contact area, and the initial rolling angle are extracted after a systematic parametric study using finite element method (FEM) simulations. The total energy of this system is defined as the sum of three terms: the elastic energy stored in the deformed micro-cylinder, the interfacial energy within the contact area, and the mechanical potential energy that depends on the external moment applied to the cylindrical micro-object. A careful examination of the energy balance of the system confirms that the rolling resistance per unit cylindrical length can be simply expressed by “work of adhesion times cylindrical radius” independent of the Young’s modulus. In addition, extending a linear elastic fracture mechanics based approach in the literature, the exact closed-form asymptotic solutions for the critical conditions for initial rolling are obtained; these asymptotic solutions are found in excellent agreement with the full-field FEM results. The values obtained from the theoretical predictions are also compared favorably with existing experimental results. Furthermore, recent and past experimental results on manipulating a cylindrical micro-object by a single probe are shown, and potential contributions for the next-generation fabrication technology are discussed.
PM04.13: Block-Co-Polymers
Session Chairs
Thursday PM, November 30, 2017
Sheraton, 3rd Floor, Fairfax A
3:30 PM - PM04.13.01
Substrate Pattern Guided Ordered Phase Separation and Miniaturization in Polymer Blend Thin Films
Nandini Bhandaru 2 , Rabibrata Mukherjee 1
2 , Indian Institute of Technology Kanpur, Kanpur India, 1 , Indian Institute of Technology Kharagpur, Kharagpur India
Show AbstractGuided self-assembly of ultrathin polymer films on a topographically patterned substrate can be a useful route to nano and micro fabrication, particularly as the ordering is achieved during film preparation itself eliminating any post-processing such as thermal or solvent vapor annealing. These surfaces have the potential to be applied in areas such as anti–reflection coatings, organic solar cells, templates in tissue engineering and selective deposition, multifunctional substrates for combinatorial studies and many more. With this work we investigate the substrate topography induced self-assembly of an immiscible polymer blend, with synergistic interactions between dewetting and phase separation leading to formation of structures with high symmetry. Polystyrene (PS) / poly(methylmethacrylate) (PMMA) blend thin films of various concentrations and compositions were spin coated on flat as well as on different topographically patterned substrates, and myriad of complex nanostructures were obtained. The morphologies were classified into three broad regimes based on the blend concentration (Cn). It was observed that for a particular topography and a specific blend composition, there exists a critical blend concentration (Cn*) below which the solution spin dewets resulting in isolated polymer droplets or threads aligned along substrate grooves. Above Cn* the overall morphology of the film transforms from discontinuous to continuous. The physical confinement imposed by the topographic patterns enables precise ordering of these domains along the substrate which are random otherwise, and significant miniaturization of the domain size was also achieved as compared to flat substrates. While the extent of ordering of the domains gradually diminish with increase in film thickness (vis-à-vis Cn), the size of the domains remains much smaller, resulting in significant downsizing of the features. Further, this method of miniaturization was developed into a facile method for creating large area coatings with excellent broad band anti reflection properties.
3:45 PM - PM04.13.02
Directed Self-Assembly of Mesoscale Eutectic Architectures via High-Operating-Temperature Direct Ink Writing
John Boley 1 , Kundan Chaudhary 1 , Thomas Ober 1 , Mohammedreza Khorasaninejad 1 , Wei Ting Chen 1 , Erik Hanson 2 , Ashish Kulkarni 3 , Jaewon Oh 4 , Jinwoo Kim 3 , Larry Aagesen 2 , Alexander Zhu 1 , Federico Capasso 1 , Katsuyo Thornton 2 , Paul Braun 3 , Jennifer Lewis 1
1 , Harvard University, Cambridge, Massachusetts, United States, 2 Materials Science and Engineering, University of Michigan–Ann Arbor, Ann Arbor, Michigan, United States, 3 Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States, 4 , University of Waterloo, Waterloo, Ontario, Canada
Show AbstractControlling nanoscale features within mesoscale architectures is a powerful, yet challenging, manufacturing objective. Lithography and light-based printing techniques provide the high throughput, large build volumes, and fine size control necessary for this goal, but require multiple processes to realize target compositions and forms. Self-assembly processes offer a low-cost way to create mesoscale features comprising ensembles of nanoscale frameworks. Specifically, directionally solidified eutectics enable the production of large scale parts containing periodically arranged sub-units whose lattice spacing can be controlled over multiple orders of magnitude and motifs span a broad range of complexities. As such, this class of materials is well suited for numerous potential technical applications, such as photonic devices. However, current fabrication methods for eutectics are limited in their range of attainable geometries. To overcome this limitation, we utilize high operating temperature direct ink writing (HOT-DIW) as an effective means to simultaneously pattern and directionally solidify eutectic materials. As a first example, we create mesoscale eutectic AgCl-KCl architectures composed of lamellar features oriented along the printing direction, whose periodic spacing can be varied between ~ 100 nm and 2 mm. Heat transfer calculations and phase field modeling are carried out to understand the influence of key printing parameters on their directional solidification. Given their periodicity, these mesoscale eutectic architectures serve as diffraction gratings that manipulate light in the visible and infrared regimes. By selectively etching KCl lamellae followed by coating silver onto the remaining AgCl lamellae, their diffraction efficiency is enhanced by an order of magnitude. While this demonstration focuses on a eutectic system with a lamellar nanostructure, HOT-DIW can be used to pattern nearly any material whose melting point is below 700 °C, the current maximum hot operating temperature, including polymers, glasses, and metal eutectics.
4:00 PM - PM04.13.03
Microscale Ordering of Block Copolymer Nano-Phases through Edge-Templating
Monali Basutkar 1 , Pawel Majewski 2 , Gregory Doerk 2 , Alamgir Karim 1 , Kevin Yager 2
1 , The University of Akron, Akron, Ohio, United States, 2 , Brookhaven National Laboratory, Upton, New York, United States
Show AbstractThe fabrication of next-generation nanomaterials requires a precise control of ordering at multiple lengthscales, from macro- and micro-, to nano-scale. Spontaneous self-assembly in nanostructured block copolymer (BCP) thin films produces well-ordered nanophases, but facile templating of these morphologies across larger lengthscales remains challenging. Here, we demonstrate how intentional material discontinuities - i.e. thin film edges - can be used to spontaneously align cylindrical BCP microdomains. Laser Zone Annealing (LZA) was employed to control the morphology at a nanoscale level by manipulating the annealing conditions; coupling to microscale patterning then enables control of ordering across multiple lengthscales. Intense photothermal gradients created by a highly localized laser heating leads to BCP alignment regulated by the local stress-relief direction with respect to the film boundaries. The nanoscale in-plane orientation of the cylinder-forming polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) morphology is systematically investigated as a function of processing history and film thickness, in order to elucidate the mechanism leading to the novel edge-templating effect. The presented templating strategy should enable the design of unique and regulated micro/nano-structures through the use of carefully engineered microfeatures.
4:15 PM - PM04.13.04
Numerical Simulations of Directed Self-Assembly in Di-Block Copolymer Films Using Zone Annealing and Pattern Templating
Joseph Hill 1 , Paul Millett 1
1 , University of Arkansas, Fayetteville, Arkansas, United States
Show AbstractDirected self-assembly (DSA) of block copolymers (BCPs) has been shown as a viable method to realize bulk fabrication of surface patterns with sub-20 nm feature sizes. However, much work remains to understand and optimize DSA methods in order to move this field forward. Large-scale numerical simulations of cold zone annealing have been performed and correlation between zone velocity and domain orientation has been shown. Additional simulations have been conducted to study to what degree zone velocity can be further increased while maintaining desired defect densities by combining zone annealing and chemo-epitaxy techniques. It is found that these two DSA methods do synergistically enhance long-range order with a particular relationship between thermal zone velocity and chemical template spacing. The simulations utilize a Time-Dependent Ginzburg-Landau model and parallel processing to explore relationships between the magnitude and velocity of a moving thermal gradient and the resulting BCP domain orientations and defect densities.
4:30 PM - PM04.13.05
Architected Ceramic Nanomaterials via Macromolecular Self-Assembly
Lisa Rueschhoff 1 , Luke Baldwin 1 , John Berrigan 1 , Hilmar Koerner 1 , Timothy Pruyn 1 , Matthew Dickerson 1
1 , Air Force Research Laboratory, Wpafb, Ohio, United States
Show AbstractNanoscale controlled ceramics and ceramic composites exhibit extraordinary mechanical properties, including elastic deformation and high toughness, but are difficult to fabricate using scalable production methods. The ability to control pre-ceramic polymer (PCP) patterning by using bottom-up approaches allows for the production of hierarchical ceramic components with desired mechanical properties. The combination of block copolymers (BCPs) and pre-ceramic polymers (PCPs) allows for the forced patterning of the PCPs as a result of the self-assembly of the BCPs. BCPs contain two or more chemically-distinct blocks that phase separate into well-defined nanostructures (e.g. lamella). Subsequent pyrolysis of the material converts the PCP into a structural ceramic material while removing the self-assembled BCP from the structure. In this presentation we will discuss effects of polymer chemistry, processing techniques, and film thickness on the order of BCP/PCP systems. This work can help advance nanoscale architecting of tough ceramic materials through the bottom-up technology of block copolymer (BCP) self-assembly.
4:45 PM - PM04.13.06
Highly Oriented Block Copolymer Thin-Film Fabrication by Sharp Dynamic Thermal Field Induced Self-Assembly
Monali Basutkar 1 , Saumil Samant 1 , Joseph Strzalka 2 , Alamgir Karim 1
1 , The University of Akron, Akron, Ohio, United States, 2 , Argonne National Laboratory, Lemont, Illinois, United States
Show AbstractThe ability of block copolymers (BCPs) to spontaneously microphase separate and self-assemble into well-defined nanostructures having periodicities in the range of 5 nm – 100 nm makes them highly attractive as potential candidates for next-generation applications including lithography, thin film filtration membranes and nanoelectronic devices such as capacitors, batteries and photovoltaics. In order to achieve industrially viable functional architectures, it is essential to control the microphase orientation and macroscopic alignment of these materials. Directing the self-assembly of high-interfacial area lamellar-BCP (l-BCP) nanodomains in thin films to produce vertically oriented etchable nanostructures holds much technological relevance for potential device manufacturing applications ranging from nanoelectronics to membranes. In this work, we demonstrate a template-free approach towards rapid (2 – 4 min.) fabrication of highly ordered vertical lamellar microdomains in l-BCP thin films (100 nm – 1 μm) by a one-step continuous dynamic thermal gradient process – Cold Zone Annealing-Sharp (CZA-S). CZA-S creates a thermal gradient induced strain gradient field that directs the self-assembly of l-BCPs to create vertically oriented lamellar microdomains without resorting to complex, expensive and time-consuming techniques. The facile CZA-S process has the potential for continuous large-area manufacturing of highly ordered nanomaterials on rigid as well as flexible substrates due to its inherent compatibility with the existing roll-to-roll technology. This study also reports a thorough understanding of the dynamic molecular mechanisms involved in the nanostructure formation and morphology evolution of vertically oriented BCP lamellae along the CZA-S thermal gradient tracked in real-time by in-situ Grazing Incidence Small Angle X-ray Scattering (GISAXS) studies. This work beyond being practically useful for rapid vertical ordering of l-BCP films, provides valuable insights into the structural evolution and dynamics of l-BCP ordering process, collectively providing a molecular level understanding of material-processing-morphology-efficacy relationship.