Symposium Organizers
William W. Yu Worcester Polytechnic Institute
Helen VanBenschoten Warner Babcock Institute for Green Chemistry
Andrew Wang Ocean Nanotech, LLC
BB1: Materials Synthesis and Processing Towards Green Chemistry I
Session Chairs
Monday PM, November 30, 2009
Public Garden (Sheraton - 5th Floor)
9:00 AM - **BB1.1
Green Chemistry in Materials Science.
John C. Warner 1
1 , Warner Babcock Institute for Green Chemistry, Wilmington, Massachusetts, United States
Show AbstractSociety's thirst for novel materials with specific functional requirements and appropriate cost is ever increasing. Molecular level innovation is attempting to keep pace with this demand in research and development labs around the world. In the past few years a growing sustainability awareness has placed an increasingly greater amount of attention on the impacts of our materials on human health and the environment. The field of Green Chemistry and the twelve principles that it is based upon provide a means to achieve the performance and cost goals while at the same time minimizing the environmental and toxicological impacts. This presentation will provide an overview with illustrative examples by one of the founders of the field of Green Chemistry.
9:30 AM - **BB1.2
The Surface Modification on the Surface of Magnetic Nanocrystals for Biological and Environmental Applications.
Chunjiao Zhou 1 , Pengfei Rong 2 , Wei Wang 2 , Jianda Zhou 2 , Wenjie Zhang 1 , Qiang Wan 1 , Bingsuo Zou 1 3
1 , Beijing institute of Technology, Beijing China, 2 The Radiological Department of Third Xiang-ya Hospital, Central South University, Cahngsha China, 3 School of MSE, Beijing Institute of Technology, Beijing China
Show AbstractSuperparamagnetic Fe3O4 nanocrystals synthesized by a chemical co-precipitation technique were modified with humic acid containing carboxylic acid, phenolic hydroxyl and quinone functional groups. The as- synthesized products were high soluble in water and used as magnetic resonance imaging (MRI) contrast agents and adsorbents for removal of cationic organic dye Methylene blue (MB) from neutral water. Superparamagnetic iron oxide nanoparticles with appropriate surface moiety have recently attracted a great deal of attention due to their potential biological applications[1], such as, bioseparation, biosensor, biocatalysis, hyperthermia, MRI image contrasting and specific cell labeling and tracking. Meanwhile, their applications in wastewater treatment have aroused more and more concerns, because magnetic separation techniques are generally superior to filtering or centrifugation based purification techniques, as magnetic nanoparticles could be easily extracted from the solution with high selectivity and efficiency by applying an external magnetic field [2]. In this presentation, we prepared superparamagnetic Fe3O4 nanocrystals coated with humic acid and used them as magnetic resonance imaging (MRI) contrast agents and adsorbents for removal of cationic organic dye Methylene blue (MB) from neutral water.The superparamagnetic nanocrystals were synthesized by the chemical co-precipitation of ferrous and ferric salts in a basic aqueous solution with humic acid as coating agents. Animals study was performed using adult male Wistar rats ( about 180 g). Nanoparticles were applied in a concentration of 0.6 mg of Fe/kg of rat body weight in 1mL of 0.9% NaCl solution through intravenous injection into a tail vein and the liver was scanned using a 1.5T-MR scanner before injection and at 5 minutes after injection. A common cationic organic dye Methylene blue (MB) applied in various industries was used as a model sample of organic pollutant to investigate the adsorption property of the as-synthesized products as well as bare Fe3O4 nanoparticles, humic acid powders and activated carbon particles. The concentration of MB in the solution was determined by measuring the absorbance by UV-visible spectrophotometry at 665 nm.T2WI images of a live rat obtained by magnetic resonance tomography are shown in figure 1. Only 5 minutes after injection, the liver was found to be significantly darker (figure 1b) than that before injection (figure 1a) corresponding to the increased contrast signal. The as-synthesized samples can increase the sensitivity and differentiation between normal and pathologic tissue in the liver. The humic acid coated superparamagnetic Fe3O4 nanocrystals with large numbers of functional groups have potential applications in Biological and Environmental science.
10:00 AM - BB1.3
Green Recycling of Thermoplastics by Condensed Light Energy.
Nathalie Bassil 1 , Rolland Habchi 1 , Eddy Souaid 1 , Joseph Dgheim 1 , Mario El Tahchi 1 , Georges El Haj Moussa 1
1 LPA-GBMI, Lebanese University, Fanar, Fanar, Lebanon
Show AbstractPlastic compounds that are used on a daily basis are often left to decompose in nature or burned in conventional combustion chambers. Neither of these solutions is effective because natural decomposition needs at least several decades and combustion is known to produce a lot of pollutants such as aliphatic hydrocarbons, monomers and additives [1]. One of the promising methods used is the Plasma Arc Gasification [2] which consists in creating high temperature plasma in order to gasify plastics, without incineration, and transform it into gases like H2. Even though promising, this technology is still expensive and hard to be implemented, so an alternative should be developed to try to minimize the cost while preserving and even increasing the efficiency.One possible solution to dispose of plastic materials effectively is to expose them to a laser beam [3]. In fact, absorption of radiation at the chosen wavelength provides a mechanism for transferring energy to the plastic. The absorption in the infrared spectral range causes vibrations and excitations. Relaxation and energy transfer processes convert the absorbed laser radiation to vibrational and translational kinetic energy of the system; the vibrational energy is raised sufficiently to cause bond rupture and chain cracking.Plastics undergo very specific chemical changes upon exposure to a well defined electromagnetic radiation and thus transform into monomers after an extended exposure time. Monomers are highly toxic so they should be transformed into more friendly constituents. In this study, decomposition of plastics using laser light with carbon nanotubes and hydrogen as end products is presented. The case of polyethylene is carefully studied to determine the most effective laser wavelength for each specific polymeric chain. In order to keep the cost at its minimum, a commercial laser is used. In addition, a complete description of this technology will be presented, while keeping in mind the main goal of reaching ultimate conditions where a complete decomposition is realised with zero emission of CO2 or any other undesirable gas.[1] M. J. Forrest, A. M. Jolly, S. R. Holding and S. J. Richards, (1995) Emission from processing thermoplastics Ann. occup. Hyg., Vol. 39, No. 1, pp. 35-53, 1995[2] Shakeel Ahmed, Abdullah Aitani, Faizur Rahman, Ali Al-Dawood, Fahad Al-Muhaish, (2009), Review, Decomposition of hydrocarbons to hydrogen and carbon, Applied Catalysis A: General 359 1–24[3] Leo Parts, Edgar E. Hardy, and Margaret L. Rodenburg, (1970) Laser Radiation-Induced, Residue-Free, Localized Decomposition of Some Plastics, Ind. Eng. Chem. Prod. Res. Develop., Vol. 9, No. 1.
10:15 AM - BB1.4
Highly Hydrophilic and Low-Protein-Fouling Polypropylene Membrane prepared by Surface Functionalization with High Density Sulfobetaine-Based Zwitterionic Polymer through UV-induced Surface Graft Polymerization Followed by Atom Transfer Radical Polymerization.
Yong-Hong Zhao 1 , Renbi Bai 1
1 Division of Environmental Science, National University of Singapore, Singapore Singapore
Show AbstractSulfobetaine methacrylate (SBMA), a relatively new zwitterionic polymer, was successfully tethered in high density onto polypropylene (PP) membrane surface through a UV-induced surface graft polymerization followed by surface-initiated atom transfer radical polymerization (ATRP) process. 2-Hydroxyethyl methacrylate (HEMA) was first immobilized onto PP membrane surface by UV-induced graft polymerization, and then each of the grafted poly(HEMA) chains, after coupled with 2-bromopropionyl groups, provided multiple surface initiation sites for subsequent ATRP of SBMA. Scanning electron microscope (SEM) images showed that the membrane surface was fully covered with mushroom-like surface structures of poly(SBMA) at 6 h of ATRP. Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR) confirmed the grafting of HEMA and SBMA on the membrane surface in the preparation process. From X-ray photoelectron spectroscopic (XPS) analysis, the degree of polymerization of SBMA was determined to exhibit a rapid increase with ATRP time initially and leveled off after 4 h of ATRP. Water contact angle measurements showed that the surface hydrophilicity of the PP membrane was improved significantly with the content of grafted poly(SBMA), with the lowest water contact angle of 17.4° being obtained in this study. Filtration experiment for protein solution demonstrated that most of the fouling on the modified PP membrane surface was reversible, and, after washed in a NaOH solution, as high as 91.4% of the initial pure water flux can be recovered, indicating good anti-protein-fouling performance.
11:00 AM - **BB1.5
Nanostructure Processing of Advanced Catalytic Materials.
Jackie Ying 1
1 , Institute of Bioengineering and Nanotechnology, Singapore Singapore
Show AbstractNanostructured materials are of interest for a variety of applications. This talk describes the synthesis and applications of nanostructured materials for pharmaceuticals synthesis, energy production, biomass conversion, environmental catalysis, toxic gas absorption, and green house gas sequestration. The nanostructured materials can be designed as nanocomposite materials with ultrahigh dispersion and synergistic effects between components. They are also derived in the form of nanoporous materials for the engineering of heterogeneous and heterogenized catalysts with excellent activity, selectivity and reusability.
11:30 AM - BB1.6
Flame Retardant Polymers and Nanocomposites Produced by Eco-friendly Synthetic Methods.
Romy Kirby 1 , Ravi Mosurkal 2 , Wayne Muller 1 , Jason Soares 1
1 , US Army NSRDEC, Natick, Massachusetts, United States, 2 , Independent Contractor, Lowell, Massachusetts, United States
Show AbstractThere is a tremendous interest in the area of flame-retardant (FR) materials due to their numerous applications in clothing, construction, aviation and telecommunications. Halogen-based FR polymers have been effective FR materials, but are now banned due to the release of toxic gases. Thus, there exists the need to develop a new generation of environmentally-safe, economical polymeric FR materials with efficient FR performance. Our work centers on the creation of novel polysiloxane copolymers containing boron and polysiloxane-organoclay nanocomposites from a facile, environmentally benign, solvent-free synthetic approach. It is well-known in the literature that boron is inherently thermally stable, environmentally safe and has extreme durability to air oxidation. Boron containing groups have been used to modify various polymers to improve flame retardancy. Furthermore, boroxo silanol derivatives, used as ceramic precursors, exhibit efficient FR properties.1 We have synthesized polysiloxane copolymers (PS) incorporating boron (polyborosiloxanes - PBS) without the use of solvents. Several different terpolymers, consisting of PBS containing an aromatic dianhydride (Oxy or DAH) at various phenylboronic acid (PBA)/Oxy and PBA/DAH molar feed ratios, have also been synthesized. PBS terpolymers have exhibited efficient flame and thermal properties with a decomposition temperature (Td) of 400-430°C and a heat release capacity (HRC) of 170-250 J/g-K. Concurrently, PS-organoclay nanocomposites were produced. Polymers, when combined with small amounts of organoclays, can exhibit improved thermal, mechanical and FR properties.2 Here, PS copolymers containing Oxy or DAH have been melt-blended with three different organoclays. PS-organoclay nanocomposites exhibit a Td of 400°C and an HRC of 160-200 J/g-K. A synergistic approach is being employed to determine if further enhancement of the FR properties can be achieved by creating PBS terpolymer nanocomposites. Eco-friendly synthesis, thermal and FR properties, with respect to polymer-organoclay interactions, is discussed.[1] (a) Armitage, P.; Ebdon, P.R.; Hunt, B.J.; Jones M.S.; Thorpet, F.G. Polymer Degradation and Stability, 1996, 54, 387. (b) Martín, C.; Ronda, J.C.; Cádiz, V. PolymerDegradation and Stability, 2006, 91, 747. [2] A.B. Morgan and C.A.Wilkie, (Eds.) Flame Retardant Polymer Nanocomposites, Wiley-Interscience, New York, 2007.
11:45 AM - BB1.7
Development of Switchable ``smart” Biomaterials using an Environmental Friendly Technology.
Ana Aguiar-Ricardo 1 , Telma Barroso 1 , Teresa Casimiro 1 , Eunice Costa 1 , Marcio Temtem 1
1 , REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica Portugal
Show AbstractDuring the last few years, an effort has been made to modify and improve the properties of intelligent or smart polymers and also on the preparation of sub-micron polymer or co-polymer particles, membranes and scaffolds that can be functionalized with these responsive polymers.Conventional techniques for polymer synthesis and preparation of particles or scaffolds typically use organic solvents and high T, which may be harmful. The use of supercritical carbon dioxide (scCO2) as a polymerization medium and as processing solvent offers many advantages over conventional solvents: CO2 is nontoxic, non-flammable, inexpensive and readily available in high purity from a variety of sources. Since it is a gas at normal pressure by simply reducing the pressure of the system, it is possible to easily separate the solvent from the polymer, leading to highly pure materials. ScCO2 technology is also extremely versatile to produce different porous membranes and to coat/impregnate internal or external polymeric surfaces with smart polymers or bioactive molecules.In this work, we explored the use of scCO2 technology to prepare “smart” switchable polymeric devices. In particular, we report the preparation of dual stimuli responsive chitosan scaffolds and temperature sensitive polysulfone-based membranes. The micropores generated in these matrices were coated¬/impregnated with a thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), using the non residue technology. It was proved that scCO2 can be used as a carrier to homogeneously distribute the monomer, initiator and cross-linker within the micropores of the polymeric substrate and can act as reaction medium for the polymerization reaction using the pores as microreactors. Microarchitectural analysis by scanning electron microscopy and mercury intrusion porosimetry demonstrate that the coating of the pores inner structure could be efficiently achieved without a considerable loss of porosity. The effectiveness of the supercritical assisted polymerization procedure for coating the pores on membrane surface was also evaluated by XPS analysis.Two different strategies were used to impregnate the chitosan devices: supercritical fluid impregnation for scaffold uptake with a model low molecular weight drug (ibuprofen) and bulk loading to impregnate with a model protein (bovine serum albumin). Both for ibuprofen and BSA the release appeared after several days and prolonged for several weeks. The release profiles showed a specific pattern accordingly to the parameters (pH and T).The polysulfone-based membranes exhibited a good performance in terms of valve mechanism in the pores with a complete on-off control of water permeability. The transport of BSA was used as a proof of concept and a mathematical model was developed, based on the Fick’s law and in Langmuir adsorption. Protein diffusion at temperatures below and above LCST showed sharp variation but the on-off control is different from pure water fluxes.
12:00 PM - BB1.8
Nanostructured Carbohydrate Based Materials – Economical, Green and Valuable.
Magdalena Titirici 1 , Demir-Cackan Rezan 1 , Zhao Li 1 , Kubo Shiori 1 , Niki Baccile 1 , Robin White 1 , Jelena Popovic 1 , Fernando Perez 1 , Markus Antonietti 1
1 Colloids, Max-Planck Institute for Colloids and Interfaces, Potsdam Germany
Show AbstractThe production of functional nanostructured materials starting from, cheap natural precursors using environmentally friendly processes is one of the most attractive subjects in material science today. One route towards such materials is provided by hydrothermal carbonization. Although known since 1913[1], the process had been only recently re-discovered and exploited by several groups, including ourselves.[2-10] The practical approach is very simple and consists in placing a carbohydrate or even a biomass based precursor [3,9] in an autoclave in water, followed by hydrothermal treatment overnight at 180-200°C. This process leads to spherically shaped carbonaceous materials with a high number of oxygenated functional groups residing at the surface. Since the production of such materials usually implies harsher and multi-step methodologies, this process has clear advantages, being totally green, economical, mild and fast.Here, we want to briefly present our latest results related to hydrothermal carbonization. These involve first some mechanistic studies based mainly on 13C-solid state NMR experiments [4,5] followed by ways to nanostructure such materials using the hydrothermal treatment of carbohydrates in the presence of either hard [89 or soft templates [6], their post functionalization [8] and applications as adsorbents[6], catalysts[10] or electrode materials[7].Finally, we show that nitrogen can be introduced into these carbonaceous materials in one pot reaction using nitrogen rich carbohydrates, resulting in nitrogen doped carbons with applications in electrochemistry or as CO2 sequestering sorbents [9].We believe that hydrothermal carbonization is an alternative and simple option to use wet, low value biomass, leading to useful carbonaceous materials with the majority of original carbon being sequestered in the solid, therefore also a hope to reduced the future CO2 emission. A key feature is not only the occurrence of carbonization in itself, but also the appearance as useful nanostructures with an appropriate surface chemistry. 1 F. Bergius, H. Specht H “Die Anwendung hoher Drücke bei chemischen Vorgängen”, Halle, 19132 M. M. Titirici, A.Thomas M. Antonietti, Chem. Mater, 2006, 18 (16), 3808 3 M. M. Titirici, A. Thomas, M. Antonietti, Chem. Mate., 2007, 19, 42054 M. M. Titirici, M. Antonietti, N. Baccile, Green Chem., 2008, 10, 12045 N. Baccile, G. Laurent, F. Babonneau, M. M. Titirici, M. Antonietti, J. Phys. Chem. C, 2009, 113, 96446 R. D. Cakan, N. Baccile, M. Antonietti, M. M Titirici Chem. Mater, 2009, 21, 4847 Y-S Hu, R-D Cakan, M. M Titirici, J O. Müller, R Schlögl, M Antonietti, J Maier, Angew. Chem. Int. Ed.,2008, 47, 16458 M. M Titirici, A Thomas, M Antonietti, J. Mater. Chem., 2007, 17, 34129 M. M Titirici, A Thomas M Antonietti, New J. Chem., 2007, 31, 78710 P. Makowski, R. Demir-Cakan, M. Antonietti, F. Goettmann M. M Titirici, Chem. Commun, 2008, 8, 999
12:15 PM - BB1.9
Biomass Derived Porous Carbonaceous Materials.
Robin White 1 , Maria-Magdalena Titirici 1 , Markus Antonietti 1
1 , Max Planck Institute for Colloids and Interfaces, Potsdam Germany
Show AbstractThe production of porous functional nanostructured carbonaceous materials starting from inexpensive naturally occurring precursors using environmentally friendly processes is one of the hot topics in material science today. One possible route towards such materials is provided by the hydrothermal carbonization approach (HTC) to the transformation of carbohydrate based biomass. This practical approach is very efficient and consists of the thermal dehydration / transformation of sugar based precursors in water under autoclave conditions at temperatures conventionally approaching 180 - 200 °C. This normally yields spherically shaped carbonaceous materials with functionally rich highly oxygenated surfaces. Since the production of like materials via conventional strategies employs harsher and multi-step methodologies, the HTC process has clear advantages, being totally green, economical, mild and fast. In this regard, the use of microwave assisted HTC for the preparation of such materials leads to carbonaceous materials in only a few hours and under relatively mild temperatures, therefore enhancing still further the green credentials of this approach.Herein our latest research highlights on the production of nanoporous functional carbon materials derived from carbohydrate biomass via conventional and microwave assisted HTC approaches, will be presented. The synthesis of a variety of materials will be demonstrated, including for example ordered mesoporous carbons prepared via soft-templating techniques, high volume mesoporous materials prepared from naturally occurring inorganic / carbohydrate composites (e.g. crustacean shells), and macroporous hollow carbon sphere materials prepared via latex nanoparticle templating. The successful preparation of nitrogen doped HTC materials in a simple one pot reaction using nitrogen containing carbohydrates or proteins to yield nitrogen doped carbons, is also presented. Furthermore, post chemical modification strategies are also discussed, demonstrating the efficacy of HTC base materials for the preparation of wide range of chemically modified materials. Our research provides the basis for the development of a range of highly useful materials, the properties of which are tunable in terms of texture, morphology and chemical properties. These materials are directly applicable in high value end applications in heterogeneous catalysis, electrochemistry / energy storage and CO2 sequestration. Notably these advanced materials are prepared directly from sugar-based biomass in a green, inexpensive and non-resource intensive manner; appropriate for tomorrow’s sustainable technology.
12:30 PM - BB1.10
Biodegradibility of Carbon Nanotubes Depends on Surface Functionalization.
Xinyuan Liu 1 , Robert Hurt 1 , Agnes Kane 1
1 , Brown University, Providence, Rhode Island, United States
Show AbstractRecent studies have led to increased concern about the potential adverse human health impacts of carbon nanotubes, and work is needed to understand those risks more fully and develop risk management strategies. One of the most important parameters determining the chronic pathogenic potential of a fibrous material is its durability in the human body, or biopersistence. A recent study provided the first evidence that single-walled carbon nanotubes can be biodegraded through enzymatic catalysis in a mild oxidizing medium relevant to the natural environment. The present article focuses on persistence in the body using an in vitro assay simulating the phagolysosome to study the role of carbon nanotube type and surface chemistry. Characterization by TEM and dynamic light scattering show that that biopersistence depends on carbon nanotube surface functionalization. Single-walled nanotubes with carboxylated surfaces are unique in their ability to undergo 90-day degradation in 1 mM H2O2 at a phagolysomal pH of 4-5 leading to length reduction and accumulation of solid carbonaceous debris. Ninety-day exposure of the SWNT-COOH is accompanied by the appearance of ultrafine fluorescent products in the ultra-filtrates indicative of chemical degradation. Unmodified, ozone-treated, and aryl-sulfonated tubes do not degrade under these conditions. We attribute the difference to the unique chemistry of acid carboxylation, which not only introduces COOH surface groups, but also causes collateral damage to the tubular graphenic backbone in the form of neighboring active sites that provide points of attack for further oxidative degradation. These results suggest that surface carboxylation can be a green chemistry approach in nanotube processing useful for some applications where biodegradation may improve safety, reduce environmental impact, or add function.
12:45 PM - BB1.11
Purification and Characterization of Naturally Occurring ``Green Tea” Polyflavonoids for Food Applications.
Ferdinando Bruno 1 , Kenneth Racicot 1 , Nicole Favreau 1 , Stephen Fossey 1 , Alexandra Grella 1 , Tshinanne Ndou 1
1 , U.S. Army Natick Soldier Research, Development and Engineering Center, RDECOM, Natick, Massachusetts, United States
Show AbstractEpicatechins are polyphenolic compounds found in the leaves of green tea. These flavonoids possess anti-carcinogenic, anti-oxidant and anti-inflammatory properties. Although oxidative polymerizations of epicatechins catalyzed by enzymes, such as horseradish peroxidase (HRP), have been reported, the polymeric products have never been separated into pure fractions. Here we report the separation, characterization and the antioxidant potency of the different isolated pure fractions. HPLC, 1HNMR, FT-IR TGA and UV-Visible spectroscopy are utilized for the separation/structural elucidation of the fractions. Weight average molecular weights by MALDI-TOF will be presented. Moreover, experimental work was teamed with modeling. Density functional theory calculations of partial charges suggest the preferred site for enzymatic polymerization of polyepicatechin is via the resorcinol group. However, Frontier Orbital Theory indicates polymerization through the catechol is more likely. The calculations further indicate that the salt form of the catechol bonded groups are highly conjugated. This was confirmed by the experimental measurements such as, e.g., UV-Vis. Moreover, the lowest polar fraction shows higher antioxidant potency compared to tert-butylhydroquinone (TBHQ). These novel stable polymers, synthesized using Green Chemistry, can be of interest in the highly regulated food industry.
BB2: Materials Synthesis and Processing Towards Green Chemistry II
Session Chairs
Monday PM, November 30, 2009
Public Garden (Sheraton - 5th Floor)
2:30 PM - **BB2.1
Green Nanostructure Synthesis.
Stanislaus Wong 1 2
1 , SUNY Stony Brook, Stony Brook, New York, United States, 2 , Brookhaven National Laboratory, Upton, New York, United States
Show AbstractEnvironmentally friendly synthetic methodologies have gradually been implemented as viable techniques in the synthesis of a range of nanostructures. In this work, we focus on the application of green chemistry principles to the synthesis of non-carbonaceous nanostructures. In particular, we describe advances in the use of an ambient template-directed technique as an environmentally sound, socially responsible, and cost-effective methodology that allows us to generate nanomaterials without the need to sacrifice on sample quality, purity, crystallinity, in addition to control over size and shape.
3:00 PM - BB2.2
APCVD SiCxOy Deposition as Na Barrier Layers for TCO/Low-E Glass Coatings.
W. Zhang 1 , T. Salagaj 1 , C. Jensen 1 , Karlheinz Strobl 1 , M. Davies 2
1 CVD Applications Laboratory, CVD Equipment Corporation, Ronkonkoma, New York, United States, 2 , Sixtron Advanced Materials, Dorval, Quebec, Canada
Show AbstractWe report on the experimental investigation of the use of Sixtron Advanced Materials Silane-free gas generation system to deposit a transparent SiCxOy Na diffusion barrier and anti-reflection film onto glass sheets with an APCVD deposition process. SiCxOy thin films (50-250nm thickness) with a tunable index of 1.65-1.75 are currently being deposited by APCVD On-Line float glass coating systems depositing TCO (Transparent Conductive Oxide) coatings (both for Low-E windows and for solar panel manufacturing applications) using, for example, gaseous Silane (SiH4), Propane and Oxygen. They are critical for achieving high conductivity and to improve the longevity of the TCO coating performance and act both as Na-diffusion barrier layer and anti-reflection single layer film having an intermediate index. Sixtron’s gas generation system uses a solid that is safe for shipping and thus removes many of the safety concerns involved with shipping and exchanging hazardous Silane gas cylinders at the thin film production site. A successful transfer of this alternative Si-precursor material to the proprietary CVDgCoat™ APCVD coating platform would enable the manufacturing and operation of safer and lower cost On-line and Off-line APCVD thin film glass coating systems for the fast growing coated glass sheet market driven by the growing alternative energy demand for both energy saving and energy generation material.
3:15 PM - **BB2.3
Green Synthesis of Cuprous Oxide Crystals via a High Pressure Approach.
Li Benxian 1 , Liu Xiaoyang 1 , Zhao Xudong 1
1 College of Chemistry, State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Changchun China
Show Abstract There is a growing interest in more environmentally processes in the chemical industry and new ‘Green Chemistry’ technologies are highly desired. Green chemistry efficiently utilizes (preferably renewable) raw materials, eliminates waste and avoids the use of toxic and/or hazardous reagents and solvents in the manufacture and application of chemical products. Cuprous oxide, Cu2O is an important p-type semiconductor metal-oxide with a direct band gap of 2.0 eV, which possesses unique optical and magnetic properties. Cu2O and related materials have also attracted much current research interests due to their theoretical value and application prospects. Bose–Einstein condensation of excitons has been an interesting topic in both experimental and theoretical research for the past several years. Cu2O is a very important industrial material which can be commonly used as a red pigment, a well-known antifouling agent for marine paints, and an effective photo catalyst for degradation of organic pollutants such as in dye wastewater, etc.Herein, we present a facile, elementary and very ‘green’ approach to synthesize Cu2O at very low temperature and without any assistance of the hazardous organic compounds or surfactants. The cuprous oxide crystal was prepared by the direct reaction of stoichiometric amounts of Cu and CuO with the assistance of the flux of mixed NaOH and KOH at 1.0 Gpa and 450 °C for 24 hours in a piston-cylinder-type high pressure apparatus. All the chemical reagents were analytical grade without further purification. The starting mixtures were encapsulated in a sealed platinum tube with a diameter of 3 mm and a height of 15 mm, which was separated by MgO powder from a graphite heater. The experiment was quenched before the pressure was released. In our expriment, the mechanism involved in synthesis of Cu2O can be concluded as a reverse dismutation reaction under high pressure:CuO+Cu→Cu2O. In summary, Cu2O crystals were synthesized in high yield via a high pressure approach, which is green and environmental friendly.
3:45 PM - BB2: Green Chem
BB2.4 Transferred to BB5.22
Show Abstract4:30 PM - **BB2.5
Environment-Friendly On-Demand Synthetic Methods of Spherical Nanoparticles Using Laser Irradiation in Liquid.
Naoto Koshizaki 1 , Yoshie Ishikawa 2
1 Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan, 2 Department of Advanced Materials Science, Kagawa University, Takamatsu, Kagawa, Japan
Show AbstractSolution chemistry routes have been widely used for nanoparticle preparation of various materials. However, nanoparticles thus obtained are coated with stabilizing molecules, which are generally toxic in biological system or sources of contamination in the environment. Here we report an environment-friendly on-demand method for synthesizing spherical nanoparticles using laser irradiation in liquid, by taking boron carbide (B4C) nanoparticles as an example. B4C is useful material for abrasive and shielding media in the nuclear industry, due to the extreme hardness and large neutron absorption cross-section of 10B. Boron carbide can typically be produced by carbothermal reduction of boric acid or boron oxide at a temperature over 1000°C. CVD is also employed for boron carbide particle fabrication, although BCl3 and borane gases with strong toxicity must be used as a boron source. Here, we attempted to obtain B4C spherical particles at room temperature by pulsed laser irradiation of B particles in ethyl acetate. The B powder dispersed in ethyl acetate was irradiated with a Nd:YAG laser (the third harmonic, 355 nm) operated at 10 Hz with 1.5 J cm-2 pulse-1 for 300 min. The laser beam was focused 2 mm below the suspension surface, using a lens. The particles obtained by laser irradiation were treated with HNO3 and rinsed with de-ionized water to remove unreacted raw B and by-product H3BO3. XRD spectra of particles indicate that boron particles before laser irradiation were amorphous but the peaks from B4C were observed in particles obtained by laser irradiation in ethyl acetate. SEM images revealed that connected irregular grains from 50-100 nm in raw B particles before irradiation were changed in ethyl acetate into spherical particles 50-400 nm. The irradiated raw B particles were possibly melted by laser irradiation, and converted to B droplets. C species, which were formed by decomposition of solvent molecules surrounding the B droplets, were dissolved into the B droplet. Then the spherical particles including B4C crystals formed via cooling process of the droplets. Residual C species in the melt might form a surface graphitic layer.Thus we have developed a convenient method at room temperature for synthesizing spherical B4C nanoparticles. By this method, nanoparticle synthesis and subsequent coating-structure formation on nanoparticles proceed in a single action. This surface layer may act as a stabilizer of nanoparticle solution without organic molecules, suggesting that this technique is environment-friendly. We can also point out the advantages of this technique, facile collection of the product without loss, biologically safe, and cost-effective. Thus our versatile method may surpass other chemical methods from the viewpoint of “green chemistry”, if we can reasonably overcome the difficulty in production yield of nanoparticles.
5:00 PM - BB2.6
Fabrication of Porous SiC Sheets with Controlled Porosity from Waste Clutch Boards.
Yuya Domi 1 , Shiro Shimada 1
1 , Hokkaido University, Sapporo Japan
Show AbstractWhen clutch boards are fabricated as friction sheets in automatic transmission of motorcars, useless fragments of them are disposed of. In this study, a proposal for an effective reuse of their waste clutch boards will be given. Clutch boards are composed of diatomaceous earth, carbon powder/fiber and phenol resin. When these sheets were carbonized at 600 °C in Ar, they became porous and contained excess carbon formed by decomposition of phenol resin. Reaction of excess carbon with SiO formed from Si and SiO2 at 1500 °C resulted in a mixture of porous SiC and Si (≤70 % porosity). High temperature treatment of Si containing-SiC sheets at 1700-1900 °C in vacuum made it possible to control their pore size and remove Si from SiC/Si sheets. As a result, SiC sheets having a main pore diameter range of 10 to 20 μm were produced. SiC/Si sheets with reduced porosity (< 60 %) were fabricated by heating of carbonized sheets impregnated with phenol resin in SiO gas at 1500 °C. The number of pores 5 μm decreased because the pores were filled with carbon residues from the resin. SiC sheet obtained by three times repeating the cycle of impregnated resin-heating at 1700 °C showed a tensile strength of 19 MPaAluminum-tri-sec-butoxide (ASB) solution was impregnated into carbonized sheets formed at 600 °C. This sheet was treated in SiO gas formed from Si and SiO2 at 1500 °C in Ar and then oxidized at 1400 °C in air. SiC-mullite composite sheets with porosity (70 %) were produced by reaction between SiO2 formed by oxidation and alumina from ASB. The strength measurement of the composite sheets as a function of oxidation temperature is in progress.
5:15 PM - BB2.7
Direct Decomposition of Iron oxides into Oxygen and Liquid Iron by Molten Oxide Electrolysis in a Self-Heated Cell.
Hojong Kim 1 , Shuqiang Jiao 1 , Luis Ortiz 1 , Donald Sadoway 1
1 DMSE, MIT, Cambridge, Massachusetts, United States
Show AbstractMolten oxide electrolysis is an electrochemical technique which can decompose the metal ore directly into the liquid metal and oxygen. What sets molten oxide electrolysis apart from all molten salt electrolytic technologies is its environmental advantage with no greenhouse gas emissions. Iron oxides in the form of FeO or Fe2O3 contained in a molten oxide electrolyte (CaO-MgO-Al2O3 system) are directly decomposed into liquid iron and oxygen by constant current electrolysis. The basis for the choice of the electrolyte composition lies in its liquidus temperature, ionic conductivity, viscosity and decomposition potential. The use of carbon-free anodes and an all-oxide electrolyte sets the stage for production of iron without carbon dioxide. Pure oxygen is the by-product. Important feature of this process is the self-heating effect of the cell during the electrolysis at high temperatures. To identify sensible self-heating effect of the cell, larger-scale cell has been developed. As the current passes though the electrolyte, self-heating effect due to the relatively high resistance of the electrolyte helps to increase the cell temperature during the electrolysis and maintain the cathodic products of iron as liquids. This self-heating effect makes it feasible to form a frozen electrolyte crust with hot cell operation zone, and this can substantially mitigate the corrosion and degradation of surrounding materials over long-term cell operation.
5:30 PM - **BB2.8
Preparation and Properties of Infrared Transparent Condutive Thin Films.
Yiding Wang 1 , Junjing Chen 1 , Li Li 1 , Zhenyu Song 1 , Yupeng An 1 , Yu Zhang 1
1 State Key Laboratory on Integrated Optoelectronics & College of Electronic Science and Engineering, Jilin University, Changchun, Jinlin, China
Show AbstractThis paper presents results for infrared transparent and conducting thin films based on In2O3.The films have been prepared by magnetrons sputtering equipment with different condition .Typical transmittance of 70%-80% with a film sheet resistance of 80-300Ω/square in the 3.5-5.0μrn region has been achieved.Optically transparent and electrically conductive semiconducting Oxide films have been extensively studied in recent years.Such films have been prepared by various methods.In general, these films have high visible transmittance,but are opaque in the IR wavelength range of 1-12μm IR transmissive.The infrared transparent and electrically conductive thin films are useful in certain important applications. For example, these films can be use as antistatic coatings, and while permitting a reasonable transmission coefficient for IR. Another obvious application is to serve as the conducting electrode for various optical devices where good infrared transmission is important. So,it is important to research indium oxide base infrared (2.5 ~ 5 um) transparent conduction thin films.It has been developed that preparation condition influence on properties of thin films. Such as the sputtering time, and pressure, and power, and the substrate temperature, had great influence on the crystal structure, optical and electrical properties of In2O3-based thin films. The In2O3-based thin films obtained were characterized and analyzed by Xray Diffractometry (XRD), Atomic Force Microscope (AFM), Vander Pauw Method and Fourier Transform Infrared Spectroscopy (FTIR).
Symposium Organizers
William W. Yu Worcester Polytechnic Institute
Helen VanBenschoten Warner Babcock Institute for Green Chemistry
Andrew Wang Ocean Nanotech, LLC
BB3: Materials Synthesis and Processing Towards Green Chemistry III
Session Chairs
Mathew Maye
Helen VanBenschoten
Tuesday AM, December 01, 2009
Public Garden (Sheraton - 5th Floor)
9:00 AM - **BB3.1
Intrinsic Colloidal Quantum Dots without Heavy Metal Ions as Visible and Near Infrared (NIR) Emitters.
Xiaogang Peng 1
1 , U of Arkansas, Fayetteville, Arkansas, United States
Show AbstractThe current high performance semiconductor nanocrystal (quantum dots) emitters are moslty based on cadmium and lead chalcogenides. This talk shall discuss possible alternatives to replace these current workhorse containing Class A elements. The composition includes ZnSe, InP, InAs, InCuS2, InAgS2, etc. All of the nanocrystals to be discussed shall be limited to the intrinsic ones, and d-doped quantum dots (d-dots) will be discussed in a different talk.
9:30 AM - BB3.2
Greener Synthesis of Nanoparticles Using Fine Tuned Hydrothermal Routes.
Mathew Maye 1
1 Department of Chemistry, Syracuse University, Syracuse, New York, United States
Show AbstractLike most chemical synthesis routes, the wet chemical synthesis of energy and sensor relevant nanomaterials often requires large amounts of high boiling point solvents, excess purification solvents, grams of harsh ligands per batch, and often the use of oxygen free atmospheres. These synthetic routes are also prone to poor scalability due to their requirement for high temperatures. Because of this, the potential use of metallic nanoparticles and semiconductive quantum dots (q-dots) in energy transfer and real time biosensor applications is labor intensive and expensive. We have explored an alternative route that involves the colloidal synthesis of quantum dots (e.g. CdSe, CdS, ZnS, CdSe/ZnS) and core-shell plasmonic nanoparticles (e.g. Au/Ag, Au/Pt) under well-controlled hydrothermal conditions (100-200 C) using simple inorganic precursors. The resulting nanomaterials are of high quality, and are easily processed depending upon application, and their synthesis is scalable. Finally, this method facilitates both classes of particles to be more easily surface-functionalized via direct methods, allowing tuning their properties and chemistries to specific applications.
9:45 AM - **BB3.3
Advanced Functional Nanocrystals for Bioimaging and Biosensing.
Mingyong Han 1 2
1 , Institute of Materials Research and Engineering, Singapore Singapore, 2 , National University of Singapore, Singpaore Singapore
Show AbstractColloidal semiconductor nanocrystals (quantum dots) have attracted great attention for their distinguished roles in fundamental studies and technical applications such as biological labeling and optoelectronic devices. In the last two decades, the main efforts have been focused on the preparation of size-tunable binary or core-shell nanocrystals with different emission colors. In our research, we also focus on the development of highly luminescent composition-tunable quantum dots across the whole visible spectrum. The successful preparation of high-quality composition-tunable quantum dots makes the new class of nanomaterials very promising as multicolor biological nanoprobes for imaging, sensing, and drug delivery applications. There is an emphasis on the development of ultrasensitive imaging/spectroscopic detection for multiplexed analysis at cellular or tissue levels. Quantitative multi-parameter analysis of multianalytes is being carried out, which could provide a direct way to identify sets of genes and proteins correlating with certain diseases.
10:15 AM - BB3.4
Development of Novel Full-Color-Emitting BCNO Phosphors Using Low Energy Liquid Process.
Yutaka Kaihatsu 1 , Asep Nandiyanto 1 , Ferry Iskandar 1 , Kikuo Okuyama 1
1 , HIroshima university, Higashi-hiroshima Japan
Show AbstractOxynitride and nitride compounds have excellent properties, such as non-toxicity, outstanding thermal and chemical stability, broad available range of excitation and emission wavelengths, and high luminescence efficiency upon activation using rare-earth ions. These properties make oxynitride and nitride compounds attractive for phosphor materials. However, the extreme high temperatures and pressures are generally required to produce these materials. Further, the addition to rare-earth ions (e.g. Eu2t, Ce3t, Yb2t, and Tb3t), which are required as luminescence centers, tend to be very expensive. With this reason, the development of viable methods for the production of oxynitride and nitride phosphor particles is desirable for white LED applications, which are applied with no additional of rare-earth ions, and are prepared at relatively low-temperatures and under ambient atmospheric pressure process.On the other hand, many efforts have been devoted to the preparation of carbon-based boron nitride (BCN) semiconductors for the use of semiconductors and phosphors. Theoretical studies suggest that it should be possible to use BCN materials directly. This circumstance could be possibly reached by varying the composition of BCN compounds, which is considered to tune the wavelength of emitted light across the visible light spectrum. In general, BCN compounds are expected to behave as semiconductors with specific band gap energies, which are tunable by only varying the atomic composition. This is because these materials are thought to be intermediates between graphite and hexagonal-Boron Nitride (h-BN). However, previous studies of BCN compounds indicated only single emission peaks in photoluminescence (PL) spectra. In addition, the PL intensity and quantum efficiency (QE) of existing BCN compounds are very low. To the best of our knowledge, full-color-emitting BCN phosphor materials have not been reported yet.In the present study, we found novel oxynitride BCNO phosphor particles, which is composed of Boron, Carbon, Nitrogen, and Oxygen atoms and is produced by a one-step liquid process at lower temperatures and under ambient atmospheric conditions. The carbon content concentration was the main investigation, which was controlled by additional poly-(ethylene glycol) (PEG) in the initial reactant. The result showed that by varying carbon content, the color emission of this novel BCNO phosphor particles has been easily tuned from violet to near-red regions of the PL spectrum. Interestingly, using the prepared BCNO phosphor particles, a high external QE and a broad range of excitation wavelengths could be obtained. We believe this material could be used as an alternative phosphor material.
11:00 AM - **BB3.5
Colloidal Nanoparticle Ligands, Key Players for Developing Rational and Green Colloidal Nanoparticle Synthesis Schemes.
Zeger Hens 1 , Iwan Moreels 1 , Antti Hassinen 1 , Bernd Fritzinger 1 , Jose Martins 1 , Richard Capek 1
1 , Ghent University, Gent Belgium
Show AbstractThe field of colloidal nanoparticle synthesis was radically changed in 1993 by the development of an organometallic route for the formation of colloidal cadmium chalcogenide semiconductor nanocrystals or quantum dots[1]. This so-called hot injection approach had important advantages. It gave access to dispersions of nanomaterials showing size-dependent optical properties, with a controlled nanoparticle diameter and a low size dispersion. Quickly, the hot-injection synthesis was adopted by the research community, leading to a steady improvement in terms of size and shape control and a wide range of accessible materials[2]. In spite of its success, the 1993 cadmium chalcogenide synthesis is by no means a rational synthesis. The chemicals it uses are expensive, often toxic and difficult to handle and it offers no variables other than time and temperature to control the reaction. Important improvements have been the introduction of non-coordinating solvents and the replacement of organometallic cation precursors by ordinary metal salts or metal oxides.[3,4] This evolution has made nanoparticle ligands key players for the development of colloidal nanoparticle synthesis schemes.In this contribution, we address the role of nanoparticle ligands in the rational synthesis and processing of colloidal nanoparticles, focussing on colloidal quantum dots. We start with a discussion of state-of-the-art colloidal synthesis schemes within the framework of classical nucleation theory. This includes the use of non-coordinating solvents, metal salts dissolved by ligands and the different anion precursors possible. Next, we pay attention to the in-situ observation of nanoparticle ligands by NMR. The possibilities of the technique to monitor nanoparticle ligands are addressed. It is shown in depth how NMR gives a view on the static or dynamic solvation of the nanoparticles by ligands and how it leads to an assessment of colloid stability and degradation.[5,6] At that point, we return to the colloidal quantum dot synthesis and discuss the potential of different schemes with respect to post-processing of the nanoparticles and upscaling of the synthesis in view of the NMR results. Finally, we address the status of the synthesis of Cd- and Pb-free quantum dots. [1]Murray, C. B., Norris, D. J., Bawendi, M. G., J. Am. Chem. Soc. 115, 8706-8715 (1993).[2]Murray, C. B., Kagan, C. R., Bawendi, M. G., Ann. Rev. Mat. Sc. 30, 545-610 (2000).[3]Qu, L. H.; Peng, Z. A.; Peng, X. G. Nano Letters 1, 333 (2001).[4]Yu, W. W., Peng, X. G., Angew. Chem. Int. Ed. 41, 2368-2371 (2002).[5]Hens, Z., Moreels, I., Martins, J. C., ChemPhysChem 6, 2578-2584 (2005).[6]Fritzinger, B., Moreels, I., Koole, R., Lommens, P., Hens, Z., Martins, J. C., J. Am. Chem. Soc. 131, 3024-3032 (2009).
11:30 AM - BB3.6
ZrO(FMN) − Quick and Easy Synthesis of a Novel Nanoscale Luminescent Biomarker.
Marcus Roming 1 , Heinrich Luensdorf 2 , Kurt E. J. Dittmar 2 , Claus Feldmann 1
1 Institute of Inorganic Chemistry, University of Karlsruhe, Karlsruhe Germany, 2 , Helmholtz-Zentrum für Infektionsforschung, Braunschweig Germany
Show AbstractCustom-made luminescent nanoparticles as oligofunctional entities can fulfill the demands of different optical imaging techniques and fluorescent tags ideally. Imaging ranges from the whole organism and organs to the subcellular level. Moreover, luminescent nanoparticles offer exceptional perspectives for diagnosis and therapy of cancer, arteriosclerosis, and neuro-degenerative or metabolic diseases. In the search for biocompatible and low-cost luminescent biomarkers which can be synthesized rapidly, the compound ZrO(HPO4)1-x(FMN)x (FMN: flavinmononucleotide, x = 0-1) has been identified as an example of a novel class of nanoscale hybrid materials [1,2].ZrO(HPO4)1-x(FMN)x has several important features, including quick and easy water-based synthesis, low costs of production, biocompatibility, and variable concentration of the incorporated dye, allowing a quasi-infinite number of luminescent centers. Typical key issues for quantum dots as well as metal-doped nanoparticles, such as high-temperature crystallization and core-shell type surface conditioning, do not need any consideration [3−5]. Taking all these aspects together, ZrO(HPO4)1-x(FMN)x can be a promising alternative to existing luminescent nanomaterials. Luminescence, biocompatibility and physiology have been validated in living mice and murine macrophages. The concept of dye-modified zirconyl phosphates (DMZP’s) as luminescent nanomaterials has already been extended to blue and red emission, as well as to luminescent switching.[1]M. Roming, H. Lünsdorf, K. E. J. Dittmar, C. Feldmann, submitted.[2]M. Roming, C. Feldmann, Patent application, DE 102008009541.9.[3]R. C. Somers, M. G. Bawendi, D. G. Nocera, Chem. Soc. Rev. 2007, 36, 579.[4]X. F. Yu, L. D. Chen, M. Li, M. Y. Xie, L. Zhou, Y. Li, Q. Q. Wang, Adv. Mater. 2008, 20, 4118.[5]T. T. Morgan, H. S. Muddana, E. I. Altinoglu, S. M. Rouse, T. Tabakivic, T. Tabouillot, T. J. Russin, S. S. Shanmugavelandy, P. J. Butler, P. C. Eklund, J. K. Yun, M. Kester, J. H. Adair, Nano Lett. 2008, 8, 4108.
11:45 AM - **BB3.7
Synthesis of Nontoxic Semiconductor Nanocrystals by Green Synthetic Route.
Bo Zou 1 , Ning Jiajia 2
1 State key lab of superhard material, Jilin University, Changchun China, 2 Department of material science, Jilin University, Changchun China
Show AbstractSemiconductors have attracted much attention based on their importance on foundational research and everyday applications. Comparing with bulk materials, semiconductor nanocrystals (SNs) are uniqueness for their size quantization effect and shape dependent properties, which induce potential applications of SNs in broad fields, such as light emitting diodes, lasers, solar cells, and biomedical probes. In the last decade, researches on synthesis and properties of SNs have got lots of breakthrough. Many SNs have been produced by organic approach or modified organic approach, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, and so on. However, many obtained SNs are toxic (Cd, Pb, Hg), which is to disadvantage for application and is unamiable to environment, so these SNs cannot be used widely. At the same time, many nontoxic SNs are also synthesized by organic approach, however TOP or TBP (organic phosphine) used in organic approach is also toxic. So synthesis of new-nontoxic SN by green synthetic route is urgent and necessary to application and environment.We have developed a simple, facile and nontoxic way to synthesize ZnSe nanoparticles and nanoflowes. Nontoxic olive oil was used to solution and ligand to synthesize ZnSe nanocrystals, no other solution and ligand were added in the synthesis. The green ZnSe nanoparticles and nananoflowers can also be got at ambient condition and readily scaled up. As obtained ZnSe nanocrystals with a zinc blende structure have narrow size distribution without resorting to any postsynthetic size-selective procedure. The amount of precursor played a greater role in the determination of the nanoparticle size. Polynuclear Zn complexes with multiple Zn atoms are proposed to explain the formation of ZnSe nanoflowers. This experiment applied a green synthetic strategy to synthesis of SNs. Moreover, we use other nontoxic solution and ligand to synthesize new and nontoxic SNs, such as In2S3, SnS and SnSe. Nontoxic oleylamine is used as solution and ligand, no other organic solvent were needed. By organic strategy used oleylamine as solution and ligand, these obtained SNs are all dispersed and high crystalinity. As-prepared In2S3 nanodots are 5nm in size, which showed surface restructure process in the growth. UV and PL characterizations gave the proof of the restructure process. SnS and SnSe is typical indirect semiconductor, which can be used in solar cell, lithium ion rechargeable batteries. By this green synthetic route, SnS and SnSe nanoparticales with different shape and size are produced. A simple and facile green synthetic route was used to produce green SNs. This green synthetic approach can be widely used to produce various SNs and will push the development of green synthetic chemistry.
12:15 PM - BB3.8
Production of Semiconductor Indium Tin Oxide (ITO) Nanowires by Sol-Gel Technique.
Halil Yavuz 1 , Ahmet Ozenbas 1
1 Metallurgical and Materials Engineering, Middle East Technical University, Ankara Turkey
Show AbstractSemiconductor Metal Oxide nanowires (SCMONWs), favorable materials for a various of quantum devices which have 1D interaction and huge surface-volume ratio, have been synthesized by a novel technique. Growth of nanowires is commonly performed using expensive techniques requiring high vacuum and high temperature conditions, which also consume some hazardous raw materials. The sol-gel technique employed in this study is used primarily for the fabrication of materials including metal oxides beginning from a wet-chemical solution, where low temperatures and non- vacuum conditions are utilized. Indium tin oxide (ITO) is primarily used as a transparent conducting oxide for electronics such as LCD and solar cell applications. In this work; indium tin oxide (ITO) nano particles, nano wires and thin films have been realized on the glass substrates by sol-gel technique. Structural, topographical and chemical analysis were made using XRD, SEM and EDS. 15 nm thick and 500 nm long ITO nanowires were observed in SEM analysis. The transparency of the ITO films was analyzed using UV spectrometer.
12:30 PM - BB3.9
Ionic Liquids as Reaction Media for the Synthesis of Inorganic Materials.
Anthony Powell 1 , Patricia Leyva-Bailen 1 , Paz Vaqueiro 1
1 Chemistry, Heriot-Watt University, Edinburgh United Kingdom
Show AbstractIonic liquids may be defined as low-melting-point (< 100 ° C) salts of organic materials. They offer considerable attractions in the search for environmentally-friendly solvents for synthetic chemistry. Their solvent properties are determined principally by the ability of the salt to act as a hydrogen-bond donor and/or acceptor and by the degree of localization of the charge on the anion. The unique properties (high polarity, conducting nature, low vapor pressure and viscosity) of ionic liquids have already led to their adoption as ‘green’ solvents for conventional synthetic organic chemistry. More recently, they have begun to be used for the synthesis of inorganic materials for technological applications. Ionic liquids allow such reactions to be carried out at relatively modest temperatures. In addition to the resulting energy savings, the use of low reaction temperatures frequently affords access to novel materials that may be kinetically stabilized and therefore not accessible at elevated temperatures. Here, we present some of our recent work on the preparation of inorganic materials in an ionic liquid medium. Using the ionic liquid 1-ethyl-3-methylimidazolium bromide (EMIB), we have succeeded in preparing main-group binary sulfides from component elements and simple halo-salts at temperatures as low as 150 °C; significantly lower than for conventional solid-state methods. Moreover, we have discovered that redox processes may occur in an ionic liquid. An unusual example of the controlled oxidation of sulfur to sulfate in EMIB, resulting in the formation of Langbeinite-type phases, A2B2(SO4)3, will be described. In an extension of the chemistry of oxy-anions in ionic liquids, we have also succeeded in preparing single-crystals of the mixed-anion species Ba3Cl4CO3 in EMIB at 170 °C. This material was previously obtainable only in polycrystalline form by reaction of BaCl2 and BaCO3 under fairly aggressive conditions (850 °C, in a CO2 atmosphere). The provision of single crystals has enabled the structure of this material to be determined for the first time.
BB4: Materials Synthesis and Processing Towards Green Chemistry IV
Session Chairs
Xiaoyang Liu
Helen VanBenschoten
Tuesday PM, December 01, 2009
Public Garden (Sheraton - 5th Floor)
2:30 PM - **BB4.1
One Phase Synthesis of Water-soluble Gold Nanoparticles with Control over Size and Surface Functionalities.
Eunkeu Oh 1 , Kimihiro Susumu 1 , Hedi Mattoussi 1
1 Optical Sciences Division, Code 5611, Naval Research Laboratory, Washington, District of Columbia, United States
Show AbstractWe have previously designed and synthesized an array of modular ligands made of a tunable length polyethylene glycol (PEG) appended at one end with either a thioctic acid (TA, has a terminal disulfide) or a dihydrolipoic acid (DHLA, has a terminal didithiol), and a potentially reactive group at the other end. Here we report on the use of some of these ligands to develop a simple and efficient synthetic method for preparing AuNPs in aqueous phase using HAuCl4:3H2O. Our approach yields low size distribution nanocrystals over the size range between 1.5 nm and 20 nm; this range is much wider that those of conventional methods using alkylthiol ligands. The NP size was simply controlled by varying the molar ratio of Au-to-PEG ligand precursors. Further passivation of the as-prepared AuNPs permitted in situ functionalization of the NP surface with the desired functional groups. The prepared AuNPs exhibit remarkable stability in the presence of high electrolyte concentrations, over wide range of pHs (2-13), and in the presence of strong resistance to competition from dithiothreitol (DTT). These results are a clear manifestation of the advantages offered by our synthetic approach to prepare biocompatible AuNPs, where modular, multifunctional ligands presenting strong anchoring groups and hydrophilic PEG chains are used. We will describe the synthesis procedure, optical and structural characterization of the nanocrystals and discuss the kinetics of precursor formation (prior to nanocrystal growth) and it dependence on the nature of the ligand used. Conjugation to specific biomolecules such as peptides and proteins will also be discussed.
3:00 PM - BB4.2
Mass Production of Metal (Ag, Cu) Nanoparticles for the Application of Electronic Device.
Byung-Ho Jun 1 , Yongsik Kim 1 , Junyoung Kim 1 , Donghoon Kim 1
1 , Samsung Electro-Mechanics, Suwon Korea (the Republic of)
Show AbstractThe synthesis and characterization of metal nanoparticles have attracted a great deal of attention due to their potential application in electronics, optics, and catalyst. However, the synthesis of high concentrated and large scaled metal nanoparticles was difficult from the absence of the effective starting material as a precursor and reducing agents as a reductant. The development of synthetic pathway to produce a highly yield nanoparticles is an important aspect of industrial technology. Herein, we report a simple, rapid approach to synthesize organic-soluble Cu and Ag nanoparticles in colloidal method for the application in a conductive pattern using inkjet printing. The silver nanoparticles have been synthesized in highly concentrated organic phase. The Cu nanoparticles have been synthesized by the reducing of the copper oxide materials using acid molecules in high concentrated organic phase. We have made high concentrated metal nanoinks which contain the metal nanoparticles above ~50 wt% due to their highly stable dispersibility. Furthermore, their sintering and electric conductivity properties were investigated by melting process between 200°C and 250°C for application to printed electronics.
3:15 PM - BB4.3
Ionic Liquids as a Greener Media for Synthesis of Nanoparticle Catalysts.
Priyabrat Dash 1 , Robert W. J. Scott 1
1 Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Show AbstractIonic liquids, owing to their interesting properties such as high polarity, excellent thermal stability and negligible vapor pressure, have attracted a great deal of attention as a greener media for quasi-homogeneous nanoparticle catalysis as well as for the synthesis of inorganic materials. We have found that the room temperature imidazolium-based ionic liquids are effective media for the direct synthesis of Au, Pd and bimetallic PdAu nanoparticle synthesis, and that the resulting nanoparticles are effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation and oxidation reactions. We have investigated the recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts; all of which are important factors in determining the overall “greenness” of such synthetic routes. Finally, routes developed in our laboratory which use ionic liquids as one-pot media for the synthesis of supported-nanoparticle heterogeneous catalysts via the trapping of pre-synthesized nanoparticles into porous inorganic oxide materials will be discussed.
4:00 PM - **BB4.4
Greener Silica Coating of Gold Nanoparticles.
Luis Liz-Marzan 1 , Isabel Pastoriza-Santos 1 , Jorge Perez-Juste 1
1 Departamento de Quimica Fisica, Universidade de Vigo, Vigo Spain
Show AbstractDevelopment of new strategies for silica coating of metal nanoparticles has been an important issue during the last 15 years. This research has been nourished by the numerous possibilities that silica coating offers in many fields of materials and biomaterials science, but it shows in almost all cases the limitation of being specific for a particular type of nanoparticles or surface capping agent. Whereas initially silica was reported as an ideal coating material to enhance colloidal stability of nanoparticles, provide tunable solubility in various solvents or even to tailor their size, and shape-dependent optical properties, its easy functionalization has opened up a wide range of new expectations in biomedical applications, for example as sensors, markers and probes. In particular, encoded nanoparticles have gained prominence as a fast, reliable and sensitive tool for multiplexed high-throughput screening biodiagnosis and bioimaging. The introduction of surface-enhanced Raman reporters into hybrid particles composed of plasmonic nanostructures such as gold nanoparticles or connected islands and a coating silica shell can expedite the read-out process while preserving the Raman reporter from leaching or contamination and providing a versatile surface for functionalization.The successful growth of uniform silica shells on metal nanoparticles has been long hindered by the low chemical affinity between both components. Therefore, most of the reported silica coating routes are based on priming the metal surface with coupling agents, surfactants or polymers, which are often toxic. The role of such prior surface modification is not just to increase the affinity of the metallic surface toward silica but also to provide the colloids with sufficient stability to be transferred into ethanol or iso-propanol, so that the classical Stöber method can be used for growth of uniform silica shells on the metallic cores. We have developed a rapid and simple strategy that can be applied to coat gold nanoparticles with a variety of shapes, as demonstrated for spheres (in a wide size range) and nanorods with homogeneous silica shells, which allows a high degree of control over shell thickness. This method involves using methoxy-poly(ethylene glycol)-thiol (mPEG-SH) as a coupling agent to transfer the particles into ethanol, where silica can be directly grown on the particles surface through the standard Stöber process. Cell viability studies of PEG-coated gold nanoparticles show that they are biocompatible, so this process is more friendly than previous examples. Additionally, we demonstrate that incorporation of Raman active molecules during silica growth is straightforward, thus simplifying the fabrication of SERS encoded nanoparticles.
4:30 PM - BB4.5
Controllable Mesopore-size and Outer Diameter of Silica Nanoparticles Prepared by a Novel Water/Oil-Phase Technique.
Asep Nandiyanto 1 , Yutaka Kaihatsu 1 , Ferry Iskandar 1 , Kikuo Okuyama 1
1 Dept. Chemical Engineering, Hiroshima University, Higashi Hiroshima Japan
Show AbstractTunable pore size and outer particle diameter of spherical mesoporous silica particles in the nanometer range were successfully synthesized using a novel water/oil-phase synthesis technique. This method involves (i) simultaneous hydrolytic condensation of tetraorthosilicate to form silica and polymerization of styrene into polystyrene (PS), (ii) self-assembly nanocluster silica and nanocluster PS to form silica/PSL nanoparticle, and (iii) calcination process to remove organic components and to produce mesoporous silica particle. In this study, an amino acid (e.g. lysine) was utilized to catalyze and to maintain the silica formation due to its ability in covering prepared silica after reaction. Further, another advantage of this catalyst is more harmless than other catalysts (e.g. ammonia, N2H4). The result showed spherical particles with controllable pore size (from 4 to 15 nm) and outer diameter (from 20 to 80 nm) was produced. The ability to control pore size and outer diameter was drastically altered by adjusting the concentration of styrene and hydrophobic molecules, respectively. After the preparation of particle was understood clearly, the large-molecule-adsorption performance of the prepared porous particles was conducted. As expected, relatively large organic molecules (i.e. Rhodamine B) were well-absorbed in the prepared sample but not by the commercial silica non-porous particles. With this reason, the prepared mesoporous silica particles may be used efficiently in various applications, including electronic devices, sensors, pharmaceuticals, and environmentally sensitive pursuits, due to its harmless process, compatibility for bio-application, and excellent adsorption properties.
4:45 PM - BB4.6
Mist Deposition Technique as a Green Chemical Root for Synthesizing Oxide and Organic Thin Films.
Shizuo Fujita 1 , Takumi Ikenoue 1 , Kentaro Kaneko 1 , Naoki Kameyama 1 , Takeya Okuno 1 , Nomura Taichi 1
1 , Kyoto University, Kyoto Japan
Show AbstractVapor-deposition has been an essential technique for the growth of highly functional semiconductor materials. For this purpose the use of dangerous and toxic sources of organometallics has been a solution (that is, MOCVD) but nobody believes that this technique is environmental-friendly. The purpose of using organimetallics is to supply the constituent elements in the gas-phase, because many organometallic compounds have high vapor pressures. However, we can propose another technique, which is far inexpensive and environmental-friendly compared to the use of organometallic compounds, for the growth of various oxide semiconductors. What we propose as a new green chemical root for the fabrication of semiconductor films is the mist deposition technique. Applying ultrasonic power with a transducer to a liquid solution, the solution is atomized to form mist particles consisted with precursors diluted in the solution. The averaged diameter of the mist particles is 2-3μm. These small mist particles float in the air and can be transferred by flowing gases. In this way, we can use mist particles as a deposition source of thin films, like a gas source. Mist particles of safe and inexpensive precursors may substitute for organometallic sources in depositions of thin films, and this is greatly advantageous from the viewpoints of safety, cost, and friendliness to environment. As an example we will show successful formations of ZnO thin films with the mist deposition technique. Using zinc acetate or zinc acetylacetonato as a precursor for Zn, we have obtained not only polycrystalline transparent conductive films with reasonably high conductivity but also high quality ZnO single crystal films which possess the higher mobility and smoother surface (due to the step-flow growth) compared to our MOCVD ZnO films. Other oxide thin films such as amorphous Al2O3 thin films for an insulating layer, amorphous (InxGa1-x)2O3 thin films for TFT applications, and corundum structured (FexGa1-x)2O3 single crystalline thin films showing ferromagnetism were also obtained by the mist deposition technique. Application of the mist deposition technique for organic thin films such as PEDOT-PSS, which is known as a conductive polymer and a material suitable to form good Schottky contacts to oxide semiconductors, was also investigated. Compared to conventional spin coating technique, the mist deposition is advantageous in the view points of low consumption of source materials, suitability for large area substrates, and lithography-less patterning with metal masks. The conductivity of PEDOT-PSS with doping reached 300 S/cm, al,ost comparable to spin-coated films. UV detectors with designed cut-off wavelengths have been easily formed with successive formation of oxide films and PEDOT-PSS Schottky electrodes through metal masks, effective for low-cost devices.
5:00 PM - BB4.7
Seedless Synthesis and Thermal Decomposition of Single Crystalline Zinc Hydroxystannate Cubes.
Gregory Wrobel 1 , Martin Piech 2 , Sameh Dardona 2 , Puxian Gao 1
1 Department of Chemical, Materials and Biomolecular Engineering & Institute of Materials Science, University of Connecticut, Storrs , Connecticut, United States, 2 Department of Physical Sciences, United Technologies Research Center, East Hartford, Connecticut, United States
Show AbstractSingle crystalline zinc hydroxystannate (ZnSn(OH)6) micro- and nano-cubes have been successfully grown on pure tin substrates via a seedless hydrothermal synthesis method. Each ZnSn(OH)6 cube is enclosed by six equivalent {001} crystal planes. Cube size and aerial density were adjusted by controlling reaction time and addition of diaminopropane (DAP) reagent. The hexamethylenetetramine (HMT) and DAP assisted etching of the oxidized tin metal surface is found to play an important role in the nucleation and growth of the zinc hydroxystanate cubes. Synthesis at higher zinc nitrate concentration as well as secondary growth resulted in formation of ZnO nanorods in addition to the cubes. In-situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been utilized to investigate ZnSn(OH)6 thermal decomposition process. The appearance of endothermic peak near ~540 K, attributed to the zinc hydroxystannate decomposition, was correlated with morphology changes induced via resistive thermal annealing and localized electron beam heating.
5:15 PM - BB4.8
Introducing Ecodesign in Silica Sol-gel Materials.
Niki Baccile 1 , Florence Babonneau 1 , Bejoy Thomas 1 , Thibaud Coradin 1
1 Laboratoire de Chimie de la Matière Condensée de Paris, CNRS-UPMC, Paris France
Show AbstractOver the last decade, ecodesign has been introduced as a concept and a methodological framework to identify and improve sustainability in product development. In this context, the 12 principles of Green Chemistry provide suitable guidelines for the elaboration of molecules and materials in conditions that meet some ecodesign-related criteria. Sol-gel chemistry is an interesting domain to be examined in this perspective because it was early identified as an eco-friendly process compared to the traditional routes to ceramics and glasses. Thus it is not surprising that many recent developments in sol-gel technology have, explicitly or not, addressed sustainability issues. This abstract [1] intend to present a point of view on these advances, focusing on the chemistry of silica. Starting from the typical reaction involving tetraethoxysilane hydrolysis and condensation in hydro-alcoholic media in the presence of inorganic catalysts, the current alternatives in term of precursors, solvents, catalysts and activation sources are presented. As an example of hybrid materials, the synthesis of surfactant-based mesostructured silica is commented. Manufacturing methods to nanoproducts, including sol-gel technology are also discussed in terms of sustainability. Finally, the recyclability and degradation of sol-gel silica are shortly commented. As a conclusion, some perspectives and current limitations for the development of a “greener” sol-gel chemistry are provided, extending the discussion to non-silica materials.[1] N. Baccile, B. Thomas, F. Babonneau, T. Coradin, J. Mater. Chem. 2009, submitted
BB5: Poster Session
Session Chairs
Wednesday AM, December 02, 2009
Exhibit Hall D (Hynes)
9:00 PM - BB5.1
A Greener Synthetic Route to FePd Nanoparticles using Microwave Irradiation.
Keith Porter 1
1 Synthesis Division, CEM Corporation, Matthews, North Carolina, United States
Show AbstractMagnetic FePd nanoparticles have gained much attention due to their potential applications in medical diagnoses, catalysis, magneto-optical systems, and as recording devices. Typical procedures require the use of iron pentacarbonyl, which is extremely toxic and air sensitive, making it dangerous and inconvenient to work with. Many of these procedures also require annealing at high temperatures or the use of toxic high boiling point solvents. A greener approach to magnetic PdFe nanoparticles using microwave irradiation will be described. Microwave irradiation delivers direct heating to the forming nanoparticles, resulting in quicker heating, shorter reaction times, and better results.
9:00 PM - BB5.10
Green Synthesis of Thermoresponsive Microbeads for Tissue Engineering Applications.
Eunice Costa 1 , Teresa Casimiro 1 , Maria Teresa Cidade 2 , Linda Griffith 4 5 , Paula Hammond 3 , Ana Aguiar-Ricardo 1
1 REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica Portugal, 2 Departamento de Ciências dos Materiais e CENIMAT, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica Portugal, 4 Department of Biological Engineering, MIT, Cambridge, Massachusetts, United States, 5 Cell Decision Processes Center, MIT, Cambridge, Massachusetts, United States, 3 Department of Chemical Engineering, MIT, Cambridge, Massachusetts, United States
Show AbstractThe development of stimuli-responsive cell-like hydrogel microbeads may be a useful platform for a vast array of applications in tissue engineering, such as the local modulation of cell behavior and/or sensing environmental cues of cellular microenvironment. To achieve that goal a precise control over morphology and mechanical properties of these pseudo-cells is necessary to promote optimal interaction between cells and their synthetic counterparts.Herein we report the synthesis of thermoresponsive poly n-isopropylacrylamide (PNIPAAm) hydrogel microbeads with “cell”-like size and mechanical properties similar to compliant human tissues through free-radical polymerization in supercritical carbon dioxide (scCO2). For that purpose a variety of cross-linkers and copolymers with polyethylene glycol (PEG) were explored under different experimental conditions. This green chemistry approach enables the elimination of all trace contaminants and thus renders the beads entirely biocompatible for sensitive cell cultures. Synthesis of sub-micron PNIPAAm particles using N,N-methylenebisacrylamide (MBA) as cross-linker in scCO2 had already been reported by our group. This synthesis strategy was further optimized to obtain large PNIPAAm microparticles by simultaneously using a polymerization stabilizer, namely a commercially available perfluoropolyether (Krytox), and increasing the monomer to CO2 ratio in the polymerization.In order to tune the mechanical properties of the beads, having soft epithelial tissues as a reference, two approaches were followed: (i) using more hydrophilic cross-linkers than MBA such as Di(ethethylene) glycol dimethacrylate (DEGDMA) and Glycerol dimethacrylate (GDMA); (ii) copolymerizing with an hydrophilic macromoner such as PEG acrylate. The cross-linkers DEGDMA or GDMA at the same cross-linking degree (0.7% molar ratio) lead to a slight increase in the dry beads diameter (2.6±0.3 μm for MBA, 3.2±0.3 μm for DEGDMA and 3.0±0.7 μm for GDMA). Furthermore, at a temperature below the polymer low critical solution temperature (LCST) the diameter of hydrated beads was about 1.5 times higher for hydrophilic cross-linkers (5.9±0.6 μm for MBA, 9.0±1.1 μm for DEGDMA, 8.4±0.6 μm for GDMA). At 37°C, which is above LCST, the diameter of the hydrated beads decrease to about the same as determined for the dry beads, regardless of the cross-linker used. Beads cross-linked with DEGDMA showed a lower shear moduli as accessed through oscillatory measurements on a rotational rheometer at 25°C, at a frequency of 1 Hz and 1% strain, being 896±117 Pa for MBA and 257±23 Pa for DEGDMA. In regards to PNIPAAm and PEG copolymers with DEGDMA as a cross-linker, no substantial improvement was observed in comparison with the homopolymers, although the presence of hydroxyl groups may be useful for further functionalization.Currently, experiments are being outlined on layer-by-layer assembly in order to incorporate reactive moieties and control surface properties.
9:00 PM - BB5.11
Environmental Applications of Metal-Organic Framework Materials.
Ruqiang Zou 1
1 EES-14, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show AbstractMetal-organic framework (MOF) is a new family of porous materials, the structure of which is composed of metal ion/cluster linked by organic ligand through strong coordination bonds. The flexibility of the two components has led to an extensive class of MOF structures with desirable porosity from nonporous to mesoporous sizes and ultrahigh specific surface areas, far exceeding those achieved for other porous materials. They also exhibit functionalized pore walls, and reasonable stability, making them applicable across a wide range. Herein, we present a series of novel MOFs, which exhibits especially capacity in storage, separation, detection/sensing, and purification applications related to environmental remediation.
9:00 PM - BB5.12
Supercritical Hydrothermal Synthesis of Surface Modified Metal Oxide Nanocrystals.
Seiichi Takami 1 , Kimitaka Minami 2 , Daisuke Hojo 2 , Toshihiko Arita 1 , Tadafumi Adschiri 2 1
1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, Japan, 2 Advanced Institute for Materials Research, Tohoku University, Sendai, Miyagi, Japan
Show AbstractThe increasing need to incorporate various functions of inorganic materials into nanoscale devices and biological molecules calls for technologies that synthesize functional inorganic nanoparticles. The application of inorganic nanoparticles largely depends on their surface properties, which control dispersion, hybridization, stability, etc. Currently, surface-modified transition metal oxide nanoparticles are synthesized in several manners. Many studies use the decomposition of metal complex or the hydrolysis of metal alkoxide in a mixture of an organic solvent and surfactants. These syntheses are performed in an organic solvent instead of aqueous phase because organic solvents serve as a reaction environment for the synthesis of metal oxide and the surface modification of produced nanoparticles.The authors studied the supercritical and subcritical hydrothermal synthesis of metal oxide nanoparticles using inexpensive metal sulfates or nitrates as precursors. The synthesis is performed in water at 200°C or higher, where the dielectric constants of water approaches to that of polar organic reagents. Therefore, water and organic surfactants can mix to form a single phase at the synthetic conditions. The mixture of water and surfactants works as a reaction medium for both hydrothermal synthesis and surface modification. Based on this idea, we report the hydrothermal synthesis of various surface-modified iron oxide nanoparticles by heating aqueous solution of metal ion in the presence of surface modifier agent including carboxylic acids and amines. We also show the large-scale production of surface-modified metal oxide nanoparticles using continuous flow-type reactor with a production rate of ~10 g/h.
9:00 PM - BB5.13
Effects of the Heat Treatment Conditions on the Properties and Microstructure of Silica Thin Films Prepared from Aqueous Colloidal Silica Containing Polyvinylpyrrolidone.
Masahiro Fujita 1 , Hiromiths Kozuka 2
1 Graduate School of Engineering, Kansai University, Suita, OSAKA, Japan, 2 Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, OSAKA, Japan
Show AbstractSince metal alkoxides are hydrophobic and immiscible with water, alcohols are always used as mutual solvents for homogenizing the alkoxides and water in traditional sol-gel method. Alcohols, however, are volatile, inflammable, and hence not favorable solvents to be handled in manufactures. Therefore, replacement of alcohols by water is strongly demanded in manufacturing industries. However, water has significantly much higher surface tension than alcohols, causing poor wettability of the substrates and film formability.Previously the authors group reported that the wettability of the substrates and the film formability are improved when organic polymers like polyvinylpyrrolidone (PVP), polyvinylacetamide and polyacrylamide are added to aqueous solutions of metal salts [1]. So far TiO2, ZrO2, ZnO, NiFe2O4, LaCoO3 and Y3Fe5O12 have been prepared from aqueous solutions of metal sulfates, oxychloride, nitrates and acetates. In the present work, silica coating films were prepared from aqueous colloidal silica containing PVP.PVP of viscosity average molecular weight of 630000 was dissolved in aqueous collidal silica, and served as the coating solution. Coating solutions of mole ratios, SiO2 : PVP : H2O = 1 : x : y ((x, y) = (0.05, 29), (0.5, 105), (1, 249)), were prepared where the ratio for PVP was the monomer equivalent. The precursor films were deposited on Si(100) substrates by dip-coating, and fired at 700-1200oC, where PVP was totally burned. The substrates showed poor wettability for the solution of PVP/SiO2 = 0, while they showed good wettability for the other solutions of PVP/SiO2 = 0.05, 0.5 and 1. Irrespective of the PVP content in the solutions and of the heat treatment temperature, optically transparent films were formed. However, particulate microstructure was observed in SEM images for the films fired at 700oC, revealing porous nature. The pencil hardness of the films fired at 700oC were 4H, H, and F at PVP/SiO2 = 0.05, 0.5, and 1.0, respectively, revealing an increase in porosity with increasing PVP content in solutions. However, the refractive index became close to that of silica glass, 1.458, irrespective of the PVP content in solutions when the films were heated at temperatures over 1100oC, where the films were densifided via viscous sintering. Thus densified, silica glass coatings could be obtained from aqueous colloidal silica containing PVP via heat treatment at temperatures over 1100oC. [1] T. Kishimoto, H. Kozuka, J. Mater. Res., 18, 466 (2003)[2] H. Kozuka, D. Okamoto, H. Nishikawa and K. Doi, Trans. Mater. Res. Soc. Jpn., 29, 2239 (2004)
9:00 PM - BB5.14
Supramolecular Ionic Liquids.
Michel Wathier 1 , Mark Grinstaff 1
1 Departments of Biomedical Engineering and Chemistry, Boston University, Boston, Massachusetts, United States
Show AbstractIonic liquids are “salt-like” materials held together through noncovalent electrostatic interactions that have melting points at relatively low temperatures (< 100 °C). Typically, these liquid salts are composed of a mono-cationic organic compound, such as an imidazolium or phosphonium, and a counteranion, such as a carboxylic acid or halide. Here, we report the discovery of a new class of materials, "network ionic liquids", created using multi-cationic and multi-anionic molecules. These materials possess properties not attainable with the current ionic liquids and are easily prepared from a diverse set of readily available monomers; facilitating the design of new ionic materials with a high level of molecular control. To create a network ionic liquid requires two different oppositely charge molecular structures where at least one structure possesses two and the other three or more ionic groups. We chose to prepare an ionic network using a phosphonium dication, P2+, and a tetraanion, ethylenediaminetetraacetate (EDTA4-). Geminal dication have been selected since they possess two positive charges, are symmetric compounds, and have recently been of interest in a variety of applications. By varying the mole and charge ratio of these ionic materials we can evaluate the affect of the coulombic interactions. For this purpose, we are investigating the dicationic phosphonium, P2+, as the dichloride salt (P2+:2Cl-) prepare by reaction between two equivalents of trihexylphosphine with one equivalent of 1,10-dichlorodecane at 140 °C for 24 h. This ionic liquid readily flows and is a colorless liquid. Dodecanedioic acid silver salt (DDA2-), ethylenediaminetetraacetic acid silver salt (EE), phosphonium monocation (P1+), and ethylenediaminetetraacetic acid, (EDTA4-), were prepared and mixed while maintaining the charge ratio (1:1) with the germinal dicationic IL (P2+:2Cl-). The viscosities of the ionic liquids were measured using a AR 1000 Controlled Strain Rheometer (TA Instruments). Ionic liquid P2+:2Cl- possesses a viscosity of 1000 Pa.s. Upon substitution of the mono anion, Cl-, for the tetraanion, EDTA4- with P2+ the viscosity significantly increases to 12000 Pa.s. On the other hand, the resulting ionic liquid with the dianion, DDA2-, P1+, or EE (which cannot form ionic bonds) exhibit low viscosities (less than 100 Pa.s) which confirm the importance of multiple coulombic interactions in these ionic liquids. This first investigation demonstrates the use of multi-cationic and multi-anionic molecules to prepare a new class of ionic liquids materials.
9:00 PM - BB5.15
Facile Synthesis of Ionic Liquids.
Michel Wathier 1 , Mark Grinstaff 1
1 Departments of Biomedical Engineering and Chemistry, Boston University, Boston, Massachusetts, United States
Show AbstractIonic liquids are materials held together through weak noncovalent electrostatic interactions. The phosphonium based ionic liquids such as tetradecyl(tributyl) phosphonium chloride are of wide-spread interest for applications given their favorable material properties such as low vapor pressure and high thermal, mechanical, and electrochemical stability. These ionic liquids are prepared by nucleophilic addition of tertiary phosphines to haloalkanes and as such a number of mono and di-substituted alkyl compounds have been prepared of that general structure. To increase the diversity of ionic liquid structures known and to facilitate the synthesis of more complex materials including biohybrid ones, additional synthetic transformations are needed that are well-defined, high yielding, thermodynamically favored, and user-friendly. Of these various chemical transformations, amide bond formation via an active N-hydroxysuccinimide (NHS) ester is a highly reliable, robust, and selective reaction that can be run in aqueous or nonaqueous solutions. To demonstrate the generality of this synthetic approach for creating new ionic liquids, we report the preparation of a phosphonium N-hydroxysuccinimide chloride, and the use of this ionic liquid activated ester reagent to synthesize a series of new ionic liquids. An ionic liquid bearing an NHS activate ester (IL-OSu) was prepared and reacted with a series of electronically and structurally different nucleophiles including alkyl, benzyl, and aromatic amines, and an alkyl thiol. IL-OSu was prepared by first reacting tributyl phosphine with chlorobutyric acid neat under microwave conditions at 60 oC for 15 minutes, the reaction was quantitative. Next, N-hydroxysuccinimide was reacted with it in the presence of DCC to afford IL-OSu in 87 % yield. A series of different ionic liquids were synthesized by reacting IL-OSu with the corresponding nucleophile. The general coupling procedure involved dissolving compound IL-OSu (1.2 eq) in dry dichloromethane followed by the addition of triethylamine (1.2 eq.) and the appropriate amine or thiol nucleophile (1eq) under nitrogen which led to the ionic liquids in good to high yields. The generality of this approach will facilitate the preparation of new ionic liquid materials.
9:00 PM - BB5.16
Click Chemistry for Efficient Synthesis of New Ionic Liquids.
Samantha Byrnes 1 2 , Michel Wathier 2 , Mark Grinstaff 1 2
1 Biomedical Engineering, Boston University, Boston, Massachusetts, United States, 2 Chemistry, Boston University, Boston, Massachusetts, United States
Show AbstractSamantha Byrnes, Michel Wathier, and Mark W. GrinstaffA major obstacle for any medical implant arises from the possibility of infections that can occur at the interface of the implant and the biological environment surrounding it. There has already been some success with peptide based coatings of titanium implants1 for the prevention of infections. These coatings absorb onto the titanium face to form a cell adhesion-resistant layer. We are exploring alternatives to the common cell adhesion prevention options that will offer broad-range protection. Ionic liquids and ionic networks are ionic materials that possess interesting chemical, physical, and rheological properties. Of the various ionic materials, we have focused primarily on the phosphonium based because they are highly stable, inert to catalysts, and have facile to prepare2. We describe here the preparation of ionic materials through the used of click chemistry – an azide alkyne Huisgen cycloaddition. This approach allows for the tailoring of specific compounds with very specific properties. A series of phosphonium based ionic liquids were synthesized in neat reactions at high temperatures (140°C or 60°C, respectively) between tributylphosphine and 6 – chloro – 1 hexyne, 1 – bromo – 4 chlorobutane or 1, 6 – dibromohexane in high yields (superior to 85%). These modified IL were then reacted with a variety of terminal halide species and sodium azide in an azide alkyne Huisgen cycloaddition using a copper catalyst at 60°C, the classic click chemistry reaction, to produce more complex phosphonium based ionic liquids. These pure compounds were tested for biocompatibility by assessing cell cytotoxicity against epithelial and fibroblast cell lines from lungs. The cells were exposed to varying concentrations up to 0.05mg/mL of the prepared ionic liquids for a 24 hour incubation period. After this time, no cytotoxicity was observed for these compounds. The prepared complex ionic liquids have shown strong yields, no cytotoxicity in in vitro studies and the potential to be firm candidates to prevent cell adhesion-resistant on implants to help protect against a board range of infections.1. Khoo, X.; Hamilton, P.; O’Toole, G. A.; et la. Directed Assembly of PEGylated-Peptide Coatings for Infection-Resistant Titanium Implants.2. Wathier, M.; Grinstaff, M. W. Synthesis and Properties of Supamolecular Ionic Networks; Journal of the American Chemical Society: Boston, 2008.
9:00 PM - BB5.17
Synthesis of Size Tunable PbSe NIR Emitting Nanoparticles by Green Route.
Javeed Akhtar 1 , Mohammad Malik 1 , Paul O'brien 1
1 School of chemistry, The university of manchester, Manchester United Kingdom
Show AbstractGreen chemistry is now being increasingly used to prepare low dimensional inorganic materials. We report a green approach to prepare PbSe nanoparticles using plant based renewable olive oil as solvent and stabilizing agent.PbSe nanoparticles were prepared by dual source method using lead oleate and TMSe while N,Ndiisobutylselenourea lead(II) as single source precursor. XRD of as-prepared PbSe nanoparticles showed cubic phase, and high resolution transmission electron microscope (HRTEM) revealed quasi spherical shape of PbSe nanoparticles. The size of PbSe nanoparticles can be controlled by injection temperature, concentration of precursors and growth time. Moreover a detail study of stability of as-synthesized nanoparticles under different conditions as in solid and solution state as well as under dark and light conditions was carried out.
9:00 PM - BB5.18
MS2 Bacteriophage as a Biotemplate for Semiconductor Nanoparticle Synthesis.
Brian Cohen 1 , Alain Kaloyeros 1 , Magnus Bergkvist 1
1 College of Nanoscale Science & Engineering, University at Albany, Albany, New York, United States
Show AbstractBionanofabrication offers unique opportunities for green chemical synthesis of hybrid nanoscale materials where size and shape is influenced by the biological template. The possibility to both chemically modify and genetically engineer biological structures allows numerous routes for introducing catalytic, targeting or other functional moieties to obtain multifunctional materials. Often the bionanofabrication approach is capable of circumventing traditional materials science processing that typically requires extreme conditions, which include high temperature, extreme pH and the use of hazardous, non-aqueous solvents. Cadmium Sulfide (CdS) is a group II-VI semiconductor with unique properties at the nanoscale, applicable to a variety of fields ranging from bioimaging to molecular electronics. Here we demonstrate a bionanofabrication approach employing viral capsids for synthesis of CdS nanocrystals in an aqueous environment. In this work we investigate the coliphage MS2 as a biological template for the synthesis of water-soluble CdS nanoparticles via two different reaction routes. MS2 is a robust, well-studied bacteriophage with an outer diameter of approximately 27 nm with a partially filled interior cavity. The interior of the capsid contains a single-stranded RNA molecule that is ~3600 nucleotides in length, however only a small sequence of the RNA (19 nucleotides) is required for capsid assembly and once assembled, the RNA can be hydrolyzed and removed without affecting capsid integrity. The MS2 capsid has several ~1.7 nm diameter pores allowing access of small molecules to the interior cavity where RNA and/or exposed amino acid residues can provide possible nucleation points for CdS nanocrystals growth. Thus MS2 offers a biotemplate system that allows manipulation of RNA content (i.e. cavity size) and opportunities to study fundamental aspects of bionanofabrication of inorganic materials. The effect of different chemical precursors and reaction conditions on CdS nanoparticle synthesis with/without MS2 present were investigated and analyzed by several techniques including UV-Vis, fluorescence and Raman spectroscopy, dynamic light scattering and Hi-Res TEM. Optical techniques reveal that monodisperse CdS nanocrystals with predicated fluorescent properties form in the presence of MS2 and remain stabile in aqueous solution. In fact, MS2-templated CdS nanocrystals were stable at room temperature for several weeks. Hi-Res TEM micrographs verified the presence of nanocrystals. The same reaction conditions without biotemplate present resulted in an immediate aggregation and sedimentation of larger CdS particles. Viral based bionanofabrication holds promise to enable an efficient, controlled and environmentally sustainable synthesis approach for a range of important nanomaterials. The work presented here represents an additional step forward towards those goals.
9:00 PM - BB5.19
A Template-driven Self-assembly Technique-assisted Smart Strategies for Porous Particle Design.
Asep Nandiyanto 1 , Ferry Iskandar 1 , Kikuo Okuyama 1
1 Dept. Chemical Engineering, Hiroshima University, Higashi Hiroshima Japan
Show AbstractA highly ordered arrangement of pores in particle-form with controllable pore-size and outer diameter was successfully prepared using a template-driven self-assembly technique. This technique was effective when a combination of main material and organic template was self-assembled to form composite main-material/template particles. Next, whenever heat treatment or solvent dissolution was applied to the self-assembled particle, the template was removed, and the porous particle was produced. A spray-drying method and a liquid-phase synthesis were presented in the present study, as a model of this technique. As results, a material with spherical particle-contained porous arrangement was produced. The size of pores and outer diameter could be controlled simply by adjusting the template size and changing the initial concentration of main material, respectively. The spray-drying method allowed preparation of porous particles with outer diameters larger than a hundred nanometers. However, the liquid-phase synthesis permitted synthesis of porous particles with sizes from several nanometers. The novel synthesis technique described in this study can be broadly applied to the production of various types of functional porous particle, which was confirmed by several materials (e.g. silica, titania, zirconia, alumina, yttria, and hyaluronic acid). Furthermore, the prepared porous particles may be used efficiently in various applications, including electronic devices, sensors, pharmaceuticals, and environmentally sensitive pursuits, due to its large surface area, which is confirmed by excellent catalytic and adsorption properties.
9:00 PM - BB5.2
Characterization of Enzymatically-Catalyzed Polycaprolactones.
Atul Bhangale 2 , Santanu Kundu 1 , William Wallace 1 , Kathleen Flynn 1 , Charles Guttman 1 , Kathryn Beers 1 , Richard Gross 2
2 Department of Chemical and Biological Sciences, Polytechnic Institute of NYU, New York, New York, United States, 1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Show AbstractLipase B from Candida antartica, physically immobilized on hydrophobic resins in a microfluidic device, was used to catalyze the reaction of epsilon-caprolactone to form moderate molecular mass polycaprolactones. Enzymatic catalysis eliminates the need for toxic organometallics in the polymerization process. Microfluidics allows for better control of reaction conditions and for the use of smaller solvent volumes thus reducing waste. Size-exclusion chromatography, nuclear magnetic resonance, and MALDI mass spectrometry were used to characterize the chemical composition and molecular mass of the reaction products as a function of time and temperature. It was found that, in addition to time and temperature, the nature of the hydrophobic support resin for the lipase enzyme plays a crucial role in determining molecular mass and reaction efficiency.
9:00 PM - BB5.20
Biodegradable Polymer Blends with Phosphates Oligomers.
Seongchan Park 1 , Ezra Bobo 2 , Miriam Rafailovich 1
1 Materials Science and Engineering, Stony Brook University, Stony Brook, New York, United States, 2 , University of Pennsylvania , Pennsylvania, Pennsylvania, United States
Show AbstractSince starch is not only inexpensive but completely biodegradable, starch-based polymers are a new class of biodegradable nanocomposites with nanofillers. Despite the benefits of using the starch, it is difficult for the starch-based composites to form thermoplastic polymers because the starch very brittle. Mixing starch with other more elastic polymers is difficult since very few polymers are compatible with starches. As we have previously shown, the addition of large aspect nanoparticles can help compatiblize blends, and in this case allows us to produce formulations which still retain a high measure of impact toughness. Furthermore, if these particles are impregnated with phosphorous compounds, the starch composites can also be rendered flame retardant. In this manner we show how we can produce flexible materials that can be used to replace non-degradable polymers currently used in applications for disposable products.
9:00 PM - BB5.21
Development of a Direct Indium Tin Oxide Recovery Process.
Tzu-Chi Chou 1 , Kuo-Chuang Chiu 1 , Shao-Hui Hsu 1 , Ren-Der Jean 1
1 , industrial technology research institute, Hsinchu Taiwan
Show AbstractIndium tin oxide (ITO) is widely used in transparent conductive thin films. During to the trace amount and high cost of indium metal, many researchers made their effort in recovering indium. Generally, the recovering process is combined with electrolytic purification methods and chemical purification methods to get purified indium metal. Because the traditional methods needed high costs and complicated processes, we didn’t use those to recover indium metal but tried to develop an easier method to recover ITO directly. In our method, first, we used ball mill to crash the waste ITO target. The solution and balls were carefully chosen to be easily removed by later processes. Since the solution dissolved some indium and tin, the components of ITO changed. In order to maintain the constituent of ITO, a special chelating agent was added to the ITO suspension to trap the dissolved metal ions. Finally, by controlling the calcine condition accurately, we could get a uniform ITO target with the resistivity around 10-4 ohms-cm.
9:00 PM - BB5.22
Low-Cost Solution Based Deposition and Characterization of Maghemite Thin Films.
Aylin Karakuscu 1 , Ahmet Ozenbas 1
1 Metallurgical and Materials Engineering, Middle East Technical University, Ankara Turkey
Show AbstractRecently, considerable attention has been given to the preparation of maghemite (γ-Fe203) thin films for gas sensing, catalysis and magneto-optical device applications. In the present work, we report an aqueous sol-gel process to deposit transparent maghemite thin films by spin-coating an iron nitrate containing solution on glass and quartz substrates. A series of maghemite films with a range of thickness has been prepared and characterized for crystal structure and optical behaviour. For the optimization of the structural and morphological investigations, different process parameters such as annealing temperature, annealing time and thickness of the film were considered as important variables. Maghemite thin films were prepared by spin-coating a gel solution of iron (III) nitrate dissolved in 2-methoxyethanol and acetylacetone on glass and quartz substrates. The film thickness was adjusted by changing the spinning rate of the spin coater. Annealing was carried out between 300 °C to 600 °C to investigate the phases present in the films. Viscosity of the main solution was found as 0.0035 Pa.s by viscosity measurements. TGA/DTA analyses showed that heat treatment should be done between 330 °C and 440 °C in order to produce maghemite thin films. SEM studies showed that single layer thickness of the films were between 65 and 80 nm. The structural characteristics were evaluated by changing the experimental parameters which are annealing temperature, annealing time and thickness of the films. From the X-ray diffraction analysis, maghemite formation was observed with decreasing annealing temperature, annealing time and film thickness. TEM results verified the presence of the maghemite phase by electron diffraction and selected area electron diffraction (SAED) methods. According to UV-vis results transmittance of the films decreases with increasing annealing temperature. Optical band gap of maghemite thin films were found as approximately 2.64 eV by UV-vis Spectrophotometer. Magnetic properties of maghemite thin films were also examined by VSM (vibrating sample magnetometer). The saturation magnetization (Ms) value of the maghemite film was found as 3 emu/g at 5 KOe.
9:00 PM - BB5.3
Adsorption of Phenanthrene by Dendrimers - A Fluorescence Study.
Mercy Lard 1 2 , Sijie Lin 1 , Priyanka Bhattacharya 1 , Pu Chun Ke 1
1 Department of Physics and Astronomy, Clemson University, Clemson, South Carolina, United States, 2 Department of Physics, Lund University, Lund Sweden
Show AbstractHyper-branched polymer, Poly(amidoamine) (PAMAM) dendrimer, has shown its versatile applications in nanomedicine and industrial processes. For water treatment, PAMAM dendrimers can be utilized as a “nanosponge”, which affords high selectivity and recyclable capacity for the removal of toxic metal ions, organic and inorganic solutes, and microorganisms in surface water, groundwater, and wastewater sources. Here we report an effective binding of dendrimers with Phenanthrene (Phen) – a polyaromatic hydrocarbon (PAH) commonly found in soils, estuarine waters and sediments, and other terrestrial and aquatic sites. The binding of Phen (donor) to PAMAM dendrimers, conjugated with Alexa Fluor® 350 succinimidyl ester dye (acceptor) was investigated using fluorescence resonance energy transfer (FRET) with a Varian Cary Eclipse fluorometer. The FRET of eight different molar ratios of Phen to PAMAM dendrimers was measured, and the efficiency was calculated for each. The most efficient ratio was selected for analysis of FRET at five different pH values of the mixture. The anti-correlation of the fluorescence of donor to that of the acceptor was observed to be the most efficient at a molar ratio of approximately 1 to 1. Due to the neutralization of the PAMAM dendrimer, the adsorption of the hydrophobic Phen molecule was most favorable at pH 10. Our research offers a fundamental understanding for the applications of using dendratic nanoparticles in water purification and environmental protection.
9:00 PM - BB5.4
Processing of Mesoporous Silica by Solution Plasma and Polyacrylic Acid Functionalization.
Panuphong Pootawang 1 , Nagahiro Saito 1 2 , Osamu Takai 1 3
1 Materials, Physics and Energy Engineering, Nagoya University, Nagoya Japan, 2 Molecular Design and Engineering, Nagoya University, Nagoya Japan, 3 EcoTopia Science Institute, Nagoya University, Nagoya Japan
Show AbstractThe advantages of the solution plasma process (SPP) were demonstrated in nanoparticles synthesis, organic compounds decomposition and more recently even in polymerization reaction. Since SPP is a simple, low time consuming and low toxic procedure, it has a highly potential to be used in large scale chemical processes. In this research we focused on mesoporous silica processing and polyacrylic acid (PAA) functionalization using SPP. Spherical mesoporous silica particles with high surface area were successfully prepared by ternary surfactants system, P123 nonionic triblock copolymer (EO20PO69EO20), sodium dodecylbenzene sulfonate (SDBS) and 1, 1, 2, 2, 3, 3, 4, 4, 4-nonafluoro-1-butane sulfonate (NFBS), under acid condition via simple sol-gel method. The solution plasma process (SPP) was firstly employed under controlled plasma conditions to remove the surfactants template instead of the conventional processes. The obtained mesoporous silica showed the diffraction peaks which correspond to a 2D hexagonal arrangement of mesopore structure. This regular arrangement was also confirmed by TEM images. The dispersive mesoporous silica sphere with the particle size around 3 μm was directly observed by SEM. The ability of SPP for template removal was confirmed by the FTIR spectra. After a discharge process for 15 min, the functional peaks of the surfactant system were almost disappeared. Moreover, functionalized mesoporous silica with polyacrylic acid was prepared using SPP under lower plasma conditions. The discharge time was 30 min in pure water without adding any chemical reagent as initiator.
9:00 PM - BB5.5
Investigation of 5052 Aluminum Alloy Foams Fabricated Industry Scale for Autoparts.
Bo-Young Hur 1 , Kwang-Jung Kang 2 , Byung-Su Tak 2 , Byung-Gu Kim 2 , Kwang-Ho Song 3
1 K-MEM R&D Cluster-GSNU, Gyeongsang National University , Jinju Korea (the Republic of), 2 i-Cube Center, Gyeongsang National University , Jinju Korea (the Republic of), 3 , Daelim University, Anyang Korea (the Republic of)
Show Abstract Aluminum foam has been applied to functional materials such as acoustic absorbing and impact absorbing materials. Its application is caused by its pores which exist inside of aluminum foam. As light structural materials, aluminum foam needs to be stronger because pure aluminum foam is not enough to apply to mechanical field. Therefore in this experiment, we tried to fabricate metal foam with 5052 aluminum alloy which has good strength and good manufacturability. The fabrication processes were conducted through melting, thickening, foaming, holding and cooling. In the melting stage, 50kg of commercial 5052 alloy was melted in the induction furnace. Then melted alloy was moved into mixing furnace. To increase its viscosity which can prevent to collapse of cell walls, Al-Ca granules were added into the melt during mixing. TiH2 was used as a foaming agent to thickened melt. The fabricated foam was cooled by the air to the room temperature. Fabricated foams were investigated cell structures by using microscopy and image analyzer. Porosities of the foams were 88% ~ 92% and average cell sizes were 1.8mm ~ 3.1mm. Compressive test results showed as increasing porosity from 88% to 92%, the strength was decreased from 3.5MPa to 1.5MPa. Sound absorption properties of the AA5052 foams showed higher value compared with pure aluminum foams.
9:00 PM - BB5.6
Superhydrophobic Surfaces by Supercritical Fluid Technology.
Sofia Hiort af Ornaes 1 , Charlotta Turner 2 , Oskar Werner 2 , Lars Wagberg 3
1 , SweTree Technologies, Uppsala Sweden, 2 Department of Physical and Analytical Chemistry, Uppsala University, Uppsala Sweden, 3 Department of Fiber and Polymer Technology, Royal Institute of Technology, Stockholm Sweden
Show AbstractSweTree Technologies is a plant and forest biotechnology company providing products and technologies to improve the productivity and performance properties of seedlings, wood and fiber for forestry, pulp & paper, packaging, hygiene, textile and other fiber related industries.The term superhydrophobicity is used to describe the effect when a water droplet is rolling off a surface instead of sliding (1). Superhydrophobic surfaces, like the surface of a Lotus leaf, have water-repellant and self-cleaning properties (2). In the presented study, superhydrophobic alkyl ketene dimer (AKD) surfaces were successfully produced on untreated paper surfaces by a Rapid Expansion of Supercritical CO2 Solution (RESS) process (3-5). The new method resulted in a degree of hydrophobicity, as measured by contact angles of water droplets on AKD surfaces, dramatically higher, up to 173°, compared to a conventional method consisting in melting AKD granules directly on the paper substrate, giving contact angles of around 109°. Experiments were conducted to investigate the effects of varying pre-expansion pressure (100-300 bar), pre-expansion temperature (40 and 60°C) and spraying distance (10 and 50 mm) on the properties of the treated surfaces. The surfaces were analyzed regarding AKD particle size, surface morphology and hydrophobicity with the aid of scanning electron microscopy (SEM) and contact angle measurements. The mean particle size of AKD after micronization via the RESS process was between 1 and 2 µm, depending upon the experimental conditions used. The average particle sizes of collected AKD particles were slightly smaller when using higher pre-expansion pressure and temperature as well as smaller spraying distance.1.Lafuma and D. Quere, Superhydrophobic states, Nat. Mater. 2 (2003) 457-460.2.X.-M. Li, D. Reinhoudt and M. Crego-Calama, What do we need for a superhydrophobic surface? A review on the recent progress in the preparation of superhydrophobic surfaces. Chem. Soc. Rev, 36 (2007) 1350-1368.3.Quan, O. Werner, L. Wågberg and C. Turner, Generation of superhydrophobic paper surfaces by a rapidly expanding alkyl ketene dimer – supercritical carbon dioxide solution, Journal of Supercritical Fluids, 49 (2009) 117-124.4.O. Werner, C. Quan, C. Turner, L. Wågberg and J.-C. Eriksson, International patent application, WO 2009/0054465, “Method to prepare superhydrophobic surfaces on solid bodies by rapid expansion solutions”.5.O. Werner, C. Quan, C. Turner, B. Pettersson and L. Wågberg, Properties of superhydrophobic paper prepared by rapid expansion of supercritical solution technique, submitted to Cellulose.
9:00 PM - BB5.7
A Low-temperature ``Green Chemistry" Route to Prepare Nanometric LaAlO3 Powders.
Esmeralda Mendoza 1 , Jose Escalante-Garcia 1 , Antonio Fuentes 1
1 Unidad Saltillo, Cinvestav, Ramos Arizpe, Coahuila, Mexico
Show AbstractPerovskite-type lanthanum aluminate LaAlO3 (LAP) has attracted much attention in materials science because of its application as substrate material and buffer layer for high-temperature superconductor and ferroelectric thin films. In addition, it is regarded as a promising candidate for microwave dielectric applications and as a catalyst for the oxidative coupling of methane. Bulk LAP powders are commonly prepared directly from the pure oxides, by solid state reaction at high temperatures (>1500°C). Many efforts have been made in recent years to lower the preparation temperature by using different strategies such as sol-gel, high-energy mechanical milling or self-propagating combustion synthesis, Despite all this, obtaining bulk crystalline perovskite-type lanthanum aluminate powders below typically 650°C, still remains a challenge. Herein, we propose a simple and cost-effective “green chemistry” route to prepare nanometric LaAlO3 at very low temperatures by combining readily available chemicals, a mechanically assisted solid state metathesis or displacement reaction (SSM) and the advantages of using in-situ generated alkali metal nitrates of low melting points, as reaction media. Initially, hydrated lanthanum and aluminium nitrates, La(NO3)3.6H2O and Al(NO3)3.9H2O (>99%), were mixed with NaOH in the appropriate stoichiometric ratio and milled together for a short period of time in a planetary ball mill by using zirconia mortars and balls. X-ray powder diffraction (XRD) patterns of the starting mixture obtained at this stage present only the characteristic reflections of NaNO3 proving that a mechanically assisted SSM reaction has taken place on milling. Thus, this chemical reaction involving the exchange of atomic/ionic species between the reactants, gives a high energy lattice by-product (NaNO3 in this case) and an amorphous LAP precursor. Differential thermal analysis curves of this mixture show the presence of three endothermic events at temperatures close to 230, 270 and 305°C, the latter two being assigned to an order-disorder NaNO3 transition and its melting respectively. Therefore, the resulting powder mixture was placed in high-alumina crucibles and fired for 3 hours at 350°C (ramp rate 5°C/min) to melt the NaNO3 by-product obtained after the SSM reaction and cooled thereafter to room temperature inside the furnace. As proved by XRD, the presence of the nitrate flux facilitates the crystallization/formation of the target phase which is then in a final step, isolated by washing with distilled water to remove the NaNO3 matrix. Transmission electron microscopy images show the as-prepared LAP powders consisting of nanometric but aggregated particles of approximately 20 nm size on average. Thus, by using a “green chemistry” approach, LaAlO3 nanometric particles were obtained at temperatures significantly lower than those achieved by any other method used up to now.
9:00 PM - BB5.8
Green Synthesis of Gold Nanoparticles with Controllable Sizes and Surface Properties as Bio-nanoprobes.
Peter Njoki 1 , Martha Kamundi 1 , Stephanie Lim 1 , Chuan-Jian Zhong 1
1 Department of Chemistry , State University of New York at Binghamton, Binghamton, New York, United States
Show AbstractThe development of effective strategies for the synthesis of metal nanoparticles with controllable size, shape, and composition in an environmentally benign approach is essential if the nanoparticles are to be commercialized with minimal environmental impacts. We have synthesized Au nanoparticles with an average size from 10 - 100 nm using green precursors like citrate and acrylate in aqueous solution. These nanoparticles are exploited for their novel spectroscopic properties in bioassays, drug delivery and catalysis. One example involves using gold nanoparticles as probes for biological detection, medical diagnostics, or controlled drug delivery. This poster describes the results of an investigation of methods for synthesizing water-soluble gold nanoparticles in the range of 10 - 100 nm with high monodispersity. The control over size and surface properties of the nanoparticles are systematically studied by manipulating the precursor concentration, reaction temperature, capping agent, and other synthesis conditions. The nanoparticles are characterized using spectroscopic and microscopic methods such as TEM, UV-Vis and SERS. Preliminary results from a study of gold nanoparticles with different sizes and surface properties for the detection of DNA will also be discussed.
9:00 PM - BB5.9
Influence of Precursor and Power Irradiation on the Microwave-assisted Synthesis of ZnS Nanoparticles.
Alejandro Vazquez 1 , Idalia Gomez 1 , Juan Aguilar 1 , Boris Kharisov 1
1 Chemistry, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, Mexico
Show AbstractResults on the synthesis of ZnS nanoparticles from ZnSO4 and Zn(CH3COO)2 as precursors in aqueous dispersion under microwave heating conditions (MW) are reported. A MW-oven (1650 W) operating at 60 and 100% of the nominal power in periods for 60 seconds was employed. The obtained dispersions were analyzed by UV-visible spectroscopy, X-ray diffraction, photoluminescence, and transmission electron microscopy. The results show that the dispersions concentration depends mainly on the applied power; meanwhile the optical properties are related with the employed precursors. ZnS nanoparticles with a mean radius of 7.1 nm and hexagonal morphology were obtained.
Symposium Organizers
William W. Yu Worcester Polytechnic Institute
Helen VanBenschoten Warner Babcock Institute for Green Chemistry
Andrew Wang Ocean Nanotech, LLC
BB6: Materials Synthesis and Processing Towards Green Chemistry V
Session Chairs
Wednesday AM, December 02, 2009
Public Garden (Sheraton - 5th Floor)
9:30 AM - **BB6.1
Greener Approaches to Biocompatible Nanoparticles.
Horst Weller 1
1 Physical Chemistry, University of Hamburg, Hamburg Germany
Show AbstractThis talk describes recent developments in the synthesis of biocompatible nanoparticles. This includes greener approaches for the preparation of quantum dots and other nanoparticles as well as new concepts of ligand design. We will discuss a variety of polyethylen oxide (PEO, PEG) containing ligands which yield extraordinary stability in biological environment and guarantee long circulation times under in vivo conditions. It is shown that the ligand chemistry decisively influences the toxicity of the particles. We finally present in vivo tumor targeting with less toxic quantum dots.
10:00 AM - BB6.2
Fabrication and Characterization of High Density Photovoltaic Film using Chalcopyrite Nanoparticles.
Farid Bensebaa 1 , Ludi Scoles 1
1 ICPET, National research Council, Ottawa, Ontario, Canada
Show AbstractWith all its potential for cost effective photovoltaic solar cell, CIGS nanoparticle faces significant challenges. Integration into high density film using environmentally friendly processes is the most difficult. Not only organic solvent should be avoided, but uniform and dense films are required using scalable and fast deposition process. Using monodispersed CuInSe2 nanoparticles in aqueous solution, prepared at the authors laboratory, spray and electrophoretic deposition techniques have been evaluated. Transparent conductive oxides (TCO) and molybdenum coated glass have been used as substrates. In both cases, substrate temperature and concentration of the starting materials are kept at relatively the same level. Although relatively high density films are obtained right after deposition, these films are still relatively porous for photovoltaic applications. Rapid thermal annealing is required to increase density. Present work showed that these two deposition techniques could be used to fabricate high quality photovoltaic films.
10:15 AM - **BB6.3
Synthesis of High-Quality Nanocrystals without Precursor Injection.
Charles Cao 1
1 Chemistry, University of Florida, Gainesville, Florida, United States
Show AbstractWith the growing interest in applications based on nanoscale materials comes a need for industrial-scale synthesis of colloidal semiconductor nanocrystals with uniform size and shape, and well-confined surface passivation. To date, the most successful and widely used nanocrystal synthesis relies on rapid precursor injection. However, because of the difficulty of precursor injection, it is difficult to scale up such a synthesis for making nanocrystals in large quantities (e.g., tens to hundreds of kilograms). Herein, we report a new synthesis method for producing high-quality II-VI nanocrystals (eg. CdS and CdSe) without precursor injection. This non-injection synthesis allows a detailed control of nanocrystal size and shape. In addition, because it exhibits easily controllable nanocrystal growth kinetics, such a synthesis is very important for large-scale industrial preparation of II-VI nanocrystals, where the rates of heating and cooling reaction solutions are limited in the synthesis systems. Furthermore, this non-injection synthesis can be extended for making nanocrystals of other compositions such as IV-VI and III-V semiconductor, metal and metal oxide nanocrystals.
11:15 AM - **BB6.4
Quantum Dots Green Chemistry: Low Temperature and Microwave Strategy.
Mingqiang Zhu 1 , Jun-Bing Fan 1 , Jin-Hua Liu 1 , Sheng Li 1 , Xiao-Bo Xu 1
1 The Center of Biomedical Engineering, Hunan University, Changsha, Hunan, China
Show Abstract Photoluminescent semiconductor nanocrystals or quantum dots (QDs) are of great fundamental and industrial interest because of their size-dependent photoluminescent properties. Generally, QDs are prepared on a small scale by utilizing very expensive ligands and solvents. However, the complicated combination from different ligand systems often results in the poor reproducibility of QD preparation. In addition, these methods indicate some limitations in process manipulation and material cost. Therefore, the facile large-scale preparation of low-cost QDs with commercial potential is of critical importance for many purposes. Here a large-scale preparation method for CdSe QDs employing commercial diesel as reaction medium, a relatively lower reaction temperature of 190-230°C, and nonphosphine ligands is introduced. Another alternative to prepare oleic acid-protected CdSe QDs is introduced using microwave-mediated method employing commercial diesel plus glycerol as reaction medium, lower reaction temperature at 50-140oC and nonphosphine ligands. By aid of the non-phosphine green method at rather low temperature, microwave-mediated synthetic technique produces CdSe QDs with size-tuneable photoluminescent properties. We expect the microwave-mediated synthetic method will lead to many applications including biomedical sensing and imaging, laser and photovoltaic solar energy cells.References:[1] Yu, W. W et al. Chem. Mater. 2003, 15,2854–2860. [2] Asokan, Set al. Nnotechnology 2005, 16, 2000–2011.[3] Deng, Z.; Cao, L.; Tang, F.; Zou, B J. Phys. Chem. B 2005, 109, 16671–16675.
11:45 AM - BB6.5
Spontaneous Formation of Mono- and Bi-metallic Crystals on Ge via Galvanic Displacement at Room Temperature.
Kang Yeol Lee 1 , Hee Cheul Choi 1
1 Department of Chemistry and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang Korea (the Republic of)
Show AbstractThe synthesis of metallic nanocrystals in the absence of organic stabilizing agent is beneficial for various applications, especially dealing with charge transfer through the surface of the nanocrystals. The galvanic displacement process [1,2] is a recently emerged electroless plating method, which has successfully synthesized various monometallic nanocrystals on solid and semiconductor substrates without organic stabilizing agents. We report that single-crystalline gold and gold-palladium bimetallic particles on Ge substrate have been successfully prepared by a galvanic displacement at ambient condition in organic solutions (DMF, DMSO, Pyridine) of HAuCl4 or in aqueous solution of HAuCl4 and K2PdCl4, without any additional template and reduction agents. The structure and composition distribution of the fabricated Au-Pd alloy films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The present synthetic method is very simple and fast. It can be expected that the method can be extended to the fabrication of other mono- and bi-metallic particles. Reference[1] L. A. Porter, H. C. Choi, J. M. Buriak, Nano Lett. 2, 1067 (2002).[2] M. Aizawa, A. Cooper, M. Malac, J. M. Buriak, Nano Lett. 5, 815 (2005).
12:00 PM - BB6.6
Direct Electrospinning of Alkoxide-Based Precursors- Sustainable Engineering of Ceramic Gel Fibers for Applications in Thermal Barriers and Catalysis.
Vasana Maneeratana 1 2 , Clement Sanchez 2 3 , Wolfgang Sigmund 4
1 Colloid Chemistry, Max-Planck Institute for Colloids and Interfaces, Potsdam Germany, 2 Laboratoire de Chimie de la Matiere Condensee de Paris, Universite Pierre et Marie Curie Univ Paris 06 , Paris France, 3 Laboratoire de Chimie de la Matiere Condensee de Paris, CNRS, Paris France, 4 Materials Science & Engineering, University of Florida, Gainesville, Florida, United States
Show AbstractElectrospinning delivers new innovations in a bottom-up concept for fabricating ceramic structures ranging from fibers, particles and derivations towards hollow and mesoporous pore structures [1]. However, rarely have ceramic electrospun products been designed with the concept of sustainable chemistry principles, which may be attributed mainly to the idea that typical electrospinning theories and studies have been developed with polymeric precursors in mind. The later approach required high-temperature calcinations to remove the excess polymers, thereby resulting in greater than 90% mass loss and the generation of excessive carbon dioxide and extremely slow productive times. Recently, “direct electrospinning” was introduced as a concept utilizing new precursor design motivations. These precursors are designed for direct fabrication of a mainly ceramic gel product without any excessive waste, immediate post-production usage and low temperature phase control. Although viscous sols were initially utilized, the sensitivity in the preparation along with low and inconsistent electrospinning conditions lead to another design iteration, to thereby develop solutions with non-reacted sol-gel precursors, such as alkoxides [2, 3]. The reactivity of the alkoxides, upon exposure to the atmospheric conditions eliminates the excessive organic polymeric aids by using the stability of inorganic chain-like polymers that have the ability to entangle and thus avoid Raleigh break up of fibers into droplets. Furthermore, an increase in production rates is also accomplished since these alkoxide-based precursors are the main constituent being electrospun with little or no polymeric aids. This enhances the electrohydrodynamic fiber production in the order of 2 magnitudes. The fast fiber production rates are due to the chemical reactivity of the alkoxides with the humidity. The lack of requiring excessive organic polymer aids, consistent productivity and the rapid production times is a new angle towards a more sustainable engineering, since it provides immediate use of these ceramic gel fibers while in the green state. This talk will discuss the development of new precursors, which were designed for direct electrospinning as xerogel alumina-gel and zirconia-hybrid fibers for thermal barrier applications and titania-hybrid fibers for photochromic and photocatalytic applications. 1.Wolfgang Sigmund, J.Y., Hyun Park, Vasana Maneeratana, et. al, Processing and Structure Relationships in Electrospinning of Ceramic Fiber Systems. J. Am. Chem. Soc, 2006. 89(2):p. 395-407.2.Maneeratana, V. and W.M. Sigmund, Continuous hollow alumina gel fibers by direct electrospinning of an alkoxide-based precursor. Chem. Eng. J., 2008. 137(1):p. 137-143.3.Son, W.K., D. Cho, and W.H. Park, Direct Electrospinning of Ultrafine Titania Fibres in the Absence of Polymer Additives and Formation of Pure Anatase Titania Fibres at Low Temperature. Nanotech., 2006. 17(2006):p. 439-443.
12:15 PM - BB6.7
Spontaneous Grafting of Benzylphosphonic Acid on Steel Surface through the Aryldiazonium Salt for Application in Corrosion Protection.
Xuan Tuan Le 1 , Daniel Belanger 1
1 , Département de Chimie, Université du Québec à Montréal, Montreal, Quebec, Canada
Show AbstractOne of the most important applications of organic layer coating onto metal surfaces is the protection against corrosion. The surface pattern with mono- or multilayers can be performed either by self-assembly process or by electrografting. The efficiency of all these methods with respect to the corrosion protection is, unfortunately, limited by the poor bonding of the organic layer inhibitor onto the surfaces. As a result, studies on the covalent coating of metal surfaces with organic corrosion inhibitor by means of aryldiazonium salt chemistry are of potential interest to several recently published works. However, the performance of primer organic layer covalently grafted through the aryldiazonium salts is insufficient. Additional modification of the grafted film by a secondary layer containing silane or diol functionalities was proposed to provide a better protective efficiency. The purpose of our present work is, therefore, to identify a simple one-step method for grafting an efficient inhibitor onto steel surfaces. Classical organic corrosion inhibitors are usually compounds containing a quaternary phosphorous atom, derivatives of imidazole, oxadiazole or thiadiazole, acetylenic alcohols. Among them, thin layers of alkylphosphonic acids have been reported to be effective inhibitors against corrosion of different metals. It is thus interesting to test the anticorrosive properties of benzylphosphonic acid coated on steel surfaces.In this work, benzylphosphonic acid was directly grafted onto steel surface in aqueous acidic solution without electrochemical assistance. Scanning electron microscopy and X-ray photoelectron spectroscopy were first used in order to characterize the grafted polymer film. As the film can withstand sonication in sulfuric acid, deionized water and acetone, a covalent modification by the strong binding of aryl group to the steel is suggested. Impedance and polarization electrochemical measurements, which were performed in aqueous sulfuric acid solution, allowed investigating anticorrosive behavior of the modified samples. The polymer film grafted on the electrode surfaces creates a barrier to the interfacial electron transfer and leads to an electrode passivation. As evidenced from the SEM and electrochemical impedance spectroscopy (EIS) results, the steel substrates are completely covered by a polybenzylphosphonic acid film with very high charge transfer resistance (determined by EIS). From the polarization measurements, the inhibition efficiencies of the grafted steel samples were estimated to be approximately 100%. Furthermore, long-term stability of the grafted film in sulfuric acid was carried out and will be discussed in detail.
BB7: Materials Synthesis and Processing Towards Green Chemistry VI
Session Chairs
Wednesday PM, December 02, 2009
Public Garden (Sheraton - 5th Floor)
2:30 PM - **BB7.1
Low-Cost Mass Production of Organic Solar Cells- From Lab to Market.
Kethinni Chittibabu 1
1 , Konarka Technologies, Inc., Lowell, Massachusetts, United States
Show AbstractKonarka Technologies at Lowell, MA is in the process of commercializing organic solar cells. Three distinctive technologies- Dye Sensitized Solar Cells (DSSC), Solid State and Hybrid DSSC and Organic Photovoltaic (OPV) cells, have been explored for R2R mass production. This presentation will discuss relative advantages, issues and potential opportunities in commercializing all three organic solar cell technologies.
3:00 PM - BB7.2
End-of-Life Recycling and Reuse of Lithium Ion Battery Materials.
Matthew Ganter 1 , Brian Landi 1 3 , Thomas Seager 2 , Arnold Stux 1 , Ryne Raffaelle 1
1 NanoPower Research Labs, Rochester Institute of Technology, Rochester, New York, United States, 3 Chemical Engineering, Rochester Institute of Technology, Rochester, New York, United States, 2 Golisano Institute for Sustainability, Rochester Institute of Technology, Rochester, New York, United States
Show AbstractHigh energy density lithium ion battery systems have seen increased incorporation in products such as consumer electronics, hybrid electric vehicles, load-leveling packs, and renewable energy storage. The anticipated growth of large battery packs elevates the concern for end-of-life (EOL) impacts from these systems. A need exists for a strategy to determine the most sustainable EOL options for these battery systems; whether it is disposal, reuse, remanufacturing, or recycling. The current study investigates the recycling and reuse of commercial 18650 lithium iron phosphate (LiFePO4) battery materials using green chemistry techniques that are both environmentally friendly and low in energy consumption. Experimental techniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were used to quantify the material morphology and relative concentrations of critical materials like copper, aluminum, polymer binder, LiFePO4 cathode, and graphitic carbon. A bill of materials was constructed from the results of the characterization experiments and readily recyclable materials present in the batteries were identified. High C-rate testing with thermal fluctuations has been used to simulate accelerated life conditions followed by a post-mortem analysis of battery and electrode performance. In parallel experiments, intact cells underwent standard galvanostatic electrochemical characterization at the cell level to determine the lithium ion capacity as a function of rate, while electrodes were tested using standard electrochemical half-cell characterization with the as-received electrolyte to determine the lithium ion capacity at the electrode level. Extraction and recovery processes were developed using composite dissolution, centrifugation, and proper annealing to extract active materials from aged cells. Post-mortem analysis of the aged battery included evaluation of electrodes for morphology changes and electrochemical corrosion. The LiFePO4 active material was exposed to a series of organic solvent extraction techniques and annealing conditions in the presence of reducing and oxidizing gas conditions to remove impurities and regenerate the LiFePO4 active material. Fabrication of new cathodes using the regenerated LiFePO4 cathode materials were tested galvanostatically using 2032 coin cells. The regenerated cathode material was compared with the original half-cell characterization of the as-received electrode to quantify the efficacy of the process. In addition, the relative concentrations of each component can be used to quantify the effect of battery scale and form factor which can enable a full scale life-cycle assessment (LCA) of different battery systems.
3:15 PM - **BB7.3
Bio-inspired Energy Conversion Systems Based on Ion Channel.
Lei Jiang 1
1 Institute of Chemistry, The Chinese Academy of Sciences, Beijing China
Show AbstractInspired by nature, novel functional, multiscale interfacial materials have been developed in our group and correlative work has been reviewed [1-2], including relationship between micro- and nanostructures and special wettability, and responsive material with special structure exhibiting stimuli-driven reversible switching between superhydrophilicity and superhydrophobicity, and so on. For instance, a responsive surface modified by DNA with a fluoride-containing hydrophobic group has been reported to achieve a switch between stable superhydrophilic, metastable superdrophobic, and stable superhydrophobic states by an enthalpy-driven process [3]. Besides, by mimicking biological ion channel, complex DNA nanosystems have been constructed to investigate the tunable non-equilibrium gating behavior of nanochannels in response to transport flux [4]. Furthermore, a synthetic nanopore-DNA system can be reversibly gated by an H+ -response conformational change of motor DNA molecules [5]. Recently, K+-responsive nanochannels are achieved by conformational switching of G-quadruplex DNA immobilized onto a synthetic nanopore with asymmetrical structure [6]. Based on our previous work and inspired by photo-electric effects of halobacteria and retina [7-9], we recently construct a novel light-induced solar cell (Fig. 1a), in which photo-sensitive molecules are used as light-driven ion pumps and generate ion transmembrane motive force. Ion exchange membrane not only separates the liquid in the anode and cathode chambers but also allows ions to pass across membrane. Transmembrane ion transport and the charge imbalance on both sides of membrane caused the current and potential (Fig. 1b). In order to obtain a constant current, internal cycle of photo-sensitive molecules is necessary and can be achieved by membrane surface modification to generate surface energy gradient.References[1] Sun, T. L.; Feng, L.; Gao, X. F.; Jiang, L. Accounts of Chemical Research 2005, 38, 644-652.[2]Xia, F.; Jiang, L. Adv. Mater. 2008, 20, 2842-2858.[3]Wang, S. T.; Liu, H. J.; Liu, D. S.; Ma, X. Y.; Fang, X. H.; Jiang, L. Angew. Chem. Int. Ed. 2007, 46, 3915-3917.[4]Mao, Y. D.; Chang, S.; Yang, S. X.; Ouyang, Q.; Jiang, L. Nat. Nanotechnol. 2007, 2, 366-371.[5] Xia, F.; Guo, W.; Mao, Y. D.; Hou, X.; Xue, J. M.; Xia, H. W.; Wang, L.; Song, Y. L.; Ji, H.; Qi, O. Y.; Wang, Y. G.; Jiang, L. J. Am. Chem. Soc. 2008, 130, 8345-8350.[6] Hou, X.; Guo, W.; Xia, F.; Nie, F.-Q.; Dong, H.; Tian, Y.; Wen, L.; Wang, L.; Cao, L.; Yang, Y.; Xue, J.; Song, Y.; Wang, Y.; Liu, D.; Jiang, L. J. Am. Chem. Soc. 2009, 131, 7800-7805.[7]Gust, D.; Moore, T. A.; Moore, A. L. Accounts of Chemical Research 2001, 34, 40-48.[8]Kuhlbrandt, W. Nature 2000, 406, 569-570.[9]Iwamoto, M.; Hasegawa, C.; Sudo, Y.; Shimono, K.; Araiso, T.; Kamo, N. Biochemistry 2004, 43, 3195-3203.
4:15 PM - **BB7.4
Synthesis of Novel Fullerene Derivatives for the Application as Acceptor Materials in Polymer Solar Cells.
Youjun He 1 , Guangjin Zhao 1 , Maojie Zhang 1 , Yongfang Li 1
1 , Institute of Chemistry, Chinese Academy of Sciences, Beijing China
Show AbstractPolymer solar cells (PSCs) have attracted great attention in recent years, because of their advantages of easy fabrication, low cost, light weight and flexibility. PSCs are composed of a blend layer of conjugated polymer donor and soluble C60 derivative PCBM acceptor sandwiched between an ITO anode and a metal cathode. There are many conjugated polymers used as donors in the high efficiency PSCs, but PCBM is dominantly used as the acceptor. However, PCBM is not the perfect acceptor material for the PSCs from the viewpoint of absorption and LUMO energy level, due to that the absorption of PCBM in the visible region is very weak, which makes it little contribution on the solar light harvest of the device, and the LUMO energy level of PCBM is too low when blended with P3HT (poly(3-hexylthiophene)) as donor, which results in lower open circuit voltage of the device. In the presentation, we will report our recent progress on the synthesis of novel fullerene derivatives with better solubility, stronger visible absorption, higher electron mobility and higher LUMO energy level. The fullerene derivatives we synthesized include PCBM-like C60 derivatives, H1~H5, and the C60 derivatives with electron-donating substituents for achieving higher LUMO energy level. The fullerene derivatives were used as acceptor materials blended with P3HT as donor in the PSCs, and some of them show improved photovoltaic properties in comparison with commercial PCBM.
4:45 PM - BB7.5
Developments of Energy Absorbing Materials for Autopart Components by Aluminum Foam.
Bo-Young Hur 1 , Seung-Ryong Jeong 1 , Sun-Jung Park 2 , Hee-Taek Shin 3 , Yong-Moon Ryu 4 , Dong-Ock Kim 4
1 K-MEM R&D Cluster-GSNU, Gyeongsang National University , Jinju Korea (the Republic of), 2 , Dongsung Panel Co., Sachon, Gyeongnam, Korea (the Republic of), 3 , Bowon Light Metal Co., Hwasung, Kyeongki-do, Korea (the Republic of), 4 Materials & Processing Engineering, KATECH, Cheonan, Chungnam, Korea (the Republic of)
Show Abstract Automobile companies are attempting to develop advanced components to higher safety grade. Typical properties for safety of passengers require energy absorbing when car has an accident. For that, it needs to plastically transform except indoor space. Aluminum foams are well known as materials for absorbing energy such as sound, vibration and impact. That’s why we research about aluminum foam to apply automobile components as energy absorbing materials. Normally aluminum foam is a cellular structure material and its representative characteristic is a very high porosity. It means that even if aluminum foams are applied to autopart component, the weight increase is a few. Top industries have already started to produce prototypes and attached them to vehicle road test. However, systematic research and further development are necessary to satisfy fully needs to safety of high-performance vehicle. To improve the safety of the car, we investigated foam included bumper and crash boxes which are components of front under body part of the car. Firstly, aluminum foams were fabricated by casting method and then the pore structures such as cell size, cell wall thickness and porosity were investigated by using microscopy and image analyzer. Pore sizes were 2.0mm ~ 5.0mm and the porosities of the foams were 85~92%. Investigation of the bumper including aluminum foam was conducted through the bending test and the properties of the crash boxes which also including aluminum foams were investigated through the compressive test. The values of the bending tests were increased from 335kgf to 875kgf and energy absorbing areas were also increased after applied aluminum foams. The values of compressive tests were increased from 185kN to 220kN and also plateau areas were increased. This means that the amounts of absorbing energies were increased after applied aluminum foams into the crash boxes.
5:00 PM - BB7.6
SAPO-34 Seeds and Membranes for CO2/CH4 Separation.
Surendar Venna 1 , Moises Carreon 1
1 Chemical Engineering, University of Louisville, Louisville, Kentucky, United States
Show AbstractSAPO-34 is a silicoaluminophosphate zeolite with 8-membered ring windows (~0.38nm) displaying chabazite structure. SAPO-34 membranes have been successfully employed to separate CO2 and H2 from different gases owing to its chemical and thermal stability, unique shape selectivity, molecular sieving properties, and atomically ordered microporous structure. The control of the crystal size, extent of crystallinity, homogeneity, and preferential CO2 adsorption capacity are highly desirable properties to prepare improved SAPO-34 membranes for CO2 separation. Smaller crystal size and narrow particle size distribution potentially lead to thinner membranes, larger-accessible surface area, reduced diffusion resistance, which impact positively the SAPO-34 membrane performance in functional gas separation applications. Rational surface modification of SAPO-34 crystals will lead to membranes displaying preferential CO2 adsorption and consequently to improved membranes for CO2 separation over light gases. Herein we present the successful synthesis of SAPO-34 seeds and membranes displaying small, uniform crystal size and improved surface properties using crystal growth inhibitors such as polyethylene glycol, Brij-35 and methylene blue. The resultant SAPO-34 crystals displayed BET surface areas up to 700m2/g, enhanced CO2/CH4 adsorption ratios (>9), and crystal sizes in the ~0.6-0.9 μm range, with narrow particle size distribution.[1] Crystal growth inhibitors interacting with reactive sites of the inorganic precursors in solution helped to: 1) shorten the nucleation period, 2) prevent the aggregation of formed nuclei. and 3) form a larger number of smaller nuclei. A larger population of small nuclei after the induction period led to small crystal size SAPO-34. Alternatively, SAPO-34 and membranes were prepared by microwave assisted heating.[2] The synthesized SAPO-34 phases showing ~0.5μm crystals with narrow particle size distribution, displayed high CO2/CH4 adsorption ratios (~29). The short synthesis time, low hydrothermal temperature and smaller crystal size with narrow particle size distribution of the synthesized SAPO-34 phases, make the microwave heating an attractive and useful approach for the preparation of the thinner membranes for practical gas separation applications.The resultant SAPO-34 seeds were employed for the synthesis of membranes on α-Al2O3 and stainless steel porous supports by secondary seeded growth. The separation performance of these membranes for equimolar CO2/CH4 mixtures is presented here.[1] S.R. Venna, M.A. Carreon, J. Phys. Chem. B. 2008, 112, 16261.[2] S.R. Venna, M.A.Carreon, J. Mater. Chem. 2009, 19, 3138.
5:15 PM - BB7.7
Self-Healing Concrete.
Michelle Pelletier 1 , Arijit Bose 1
1 Chemical Engineering, University of Rhode Island, Kingston, Rhode Island, United States
Show AbstractThe building industry has taken a significant interest in “smart materials” to overcome the shortcomings of conventional materials. Many advances have been made in manipulating material properties to behave as a “sense and repair” system. Our system utilizes stress as an environmental stimulus for self-healing concrete. Glass capillaries are filled with a sodium silicate solution and incorporated randomly into the concrete mix. When mechanical stress causes a crack in the concrete, it has a tendency to propagate very quickly within the system. The stress will crack the capillary, releasing the solution into a surrounding crack or pore. Through a series of chemical reactions utilizing air and surface chemicals of the pore, the solution will ultimately form silica. This would be able to heal the cracks from within. Experiments including compressive and flexural strength have shown that the presence of glass capillaries in the concrete matrix does not affect the mechanical properties of the concrete. This material has various applications in civil engineering and infrastructure materials for building mitigation.