Symposium SM07 : Functional (Bio)polymers in Energy and Environment Applications

Biological materials provide inspiration for lightweight but mechanically excellent materials, suggesting energy efficiency especially in transportation applications. Nacre is a prototypical natural structural material combining high strength and toughness with lightweight construction due to its aligned self-assembled aragonite sheets glued by thin protein layers, thus serving as an inspiration for materials scientists. We show a facile route for nacre-mimetic composites by first coating clay nanosheets by polymers in aqueous dispersion, followed by their packing to films and their subsequent lamination for thicker sheets. This results in bulk clay/polymer nacre-mimetic nanocomposites with high clay alignment, showing strength 220 MPa and fracture toughness 3.4 MPa m^1/2, approaching those of nacre (1). The plastic phenomena at the propagating crack tip are responsible for the toughening. Such fracture processes can be followed by laser speckle methods to get information on the microscopic void formation before the major fracture (2). Cellulose nanofibers are colloidal fibers with high mechanical properties due to their internal native crystalline structure. We show a facile way for porous films thereof using a sequence of solvent exchanges. Unlike classic aerogels, whose mechanical properties do not allow tensile testing, the present aerogels/xerogels show high tensile strength of 100 MPa and Young's modulus of 6 GPa under tension. With its low density (0.6 g/cm³), this leads to high specific strength. The films were coated with single-wall carbon nanotubes via aerosol filtration from the nanotube synthesis processes. Such routes provides highly conducting transparent films, which can have potential in flexible devices.
[1] M. Morits, T. Verho, J. Sorvari, V. Liljeström, M. Kostiainen, A. Gröschel, O. Ikkala, Toughness and Fracture Properties in Nacre-Mimetic Clay/Polymer Nanocomposites, Adv. Funct. Mater., 27, 1605378, 2016.
[2] T. Verho, P. Karppinen, A. Gröschel, O. Ikkala, Imaging Inelastic Fracture Processes in Biomimetic Nanocomposites and Nacre by Laser Speckle for Better Toughness, Adv. Sci, 2017, in press.
[3] Ambient Dried Cellulose Nanofibril Aerogel Membranes with High Tensile Strength and Their Use for Aerosol Collection and Templates for Transparent, Flexible Devices, M. S. Toivonen, A. Kaskela, O. J. Rojas, E. I. Kauppinen, O. Ikkala, Adv. Funct. Mater., 25, 6618, 2015.

Water-soluble polymers are the most common materials applied for drug delivery systems, enabling drug encapsulation and slow release on-demand. The advent of 3D printing allows customization of drug carriers for patient’s needs, e.g. 3D printed oral drug delivery tablets enable personalized dosage, which will help minimize drug side effects. In addition, one can imagine designing degradable medical devices or cell scaffolds, which exhibit a complex geometry and tailored dissolution to improve drug release.

Here, we present different polymeric structures suitable for 3D printing. Each 3D printing technique requires tailored polymer properties to maximize processability. We developed water-soluble, poly(ether ester) ionomers for low-temperature material extrusion. Melt transesterification of poly(ethylene glycol) (PEG, 8 kDa) and dimethyl 5-sulfoisophthalate afforded anionically charged poly(ether ester)s of sufficient molecular weight to impart mechanical integrity. We highlight that quantitative ion exchange with divalent cations enables tailoring melt rheological properties. The latter allow for material extrusion at low temperatures (70 °C) and permit the incorporation of additional biological molecules. This is of significance because conventional water-soluble materials for material extrusion, e.g. polyvinyl alcohol require high processing temperatures of 200 °C.

Furthermore, we developed polyethylene glycol polymers to generate degradable drug delivery vehicles. These polymers are suitable for micro-stereolithographic 3D printing at micron resolution. UV-crosslinking leads to hydrogels, which are stable at physiological conditions and degrade at slightly acidic pH. These structures are promising candidates for implantation into tumor tissue, providing slow release of anti-tumor drugs.

Poly(ionic liquid) polymers (PIL, polymerized ionic liquids) have been successfully exploited in many novel ways over the past 15 years. We examine how some of these new PIL impact dispersions and coatings and describe some of their potential use in energy materials and devices.
Spontaneous nanoscopic phase separation to produce thermodynamically stable dispersions have been achieved by several approaches, including microemulsion polymerization, emulsion polymerization, and condensation polymerization. These nanogel materials provide new dispersions and coatings that also exhibit solvent, anion, and thermal stimuli-responsiveness, and this stimuli-responsiveness can be used to obtain new material properties. Such dispersions also offer approaches to creating advanced dispersions of nanocarbons and other materials, including highly thermally conducting (mid-diamond range) MWCNT coatings and nanocomposites and highly concentrated aqueous dispersions (up to 17% w/w) of MWCNT and graphene. Some of these dispersions also offer approaches to coating to obtain transparent electrodes, where coating deposition is controlled by stimuli-responsiveness.
Controlled radical polymerization has been used to create a family of triblock copolymers that also exhibit beneficial dispersion and material properties. Conventional and thermoreversible gelation offer two approaches to creating novel hydrogel materials. Condensation polymerization has recently been shown to provide an alternative approach to forming PIL gels, and these include novel materials with melting and freezing transitions at temperatures below glass transitions. Such novel gels may exemplify a synthetic glass (distinguished from glass states achieved by quenching). These glasses may offer design approaches for facilitating ionic transport while maintaining matrix rigidity. Introduction of PIL based on condensation chemistries also provides an expanded set of new and biodegradable materials.

Biofouling is an undesirable process in which a surface becomes encrusted with organisms and their by-products. This unwanted colonization has a serious impact on marine devices, as it lead to deterioration of the surfaces and can alter fluid flow rates leading to significant increase in cost of marine transportation. In the healthcare system, the attachment of bacteria and biofilm formation on medical devices may lead to severe infections and consequently death. In the US alone, the Center of Disease Control and Prevention (CDC) reported that healthcare-associated infections account for an estimated 1.7 million infections and 100,000 deaths annually.
Many approaches to prevent biofouling have been suggested, however, they suffer from drawbacks such as release of toxic materials to the surroundings, low stability that limits their long-term application or complex and expensive synthesis.
My research group designed a small molecule that can spontaneously form a coating that resists biofilm formation. The molecule contains three elements that enable i) its self-assembly, ii) its adsorption onto any substrate and iii) its antifouling activity. Our results clearly demonstrate the formation of a coating on various surfaces (glass, titanium, silicon oxide, metals and polymers). In addition, we showed that this coating prevents the first step of antifouling, which involves the adsorption of bioorganic molecules to the substrate. Moreover, the coating significantly reduces the attachment of various organisms such as bacteria and fungi to surfaces. Importantly, this peptide design can serve as a platform for the design of functional peptide-based coatings.

Copper release is central in today’s marine antibiofouling coatings for its biocidal effect at the coating-water interface of ship’s exteriors. While copper is currently, broadly accepted, its release and accumulation causes pollution of marinas and harbors and deterioration to marine life. New green antibiofouling technologies are being researched, with our interest being a coating that works on never ending uptake-release cycles utilizing copper naturally present in the sea, thus constantly cyclically replenishing its antibiofouling function. Such coatings will be environmentally benign with no net release of copper and can also remediate copper-contaminated marinas and harbors. Our newly developed glutaraldehyde-crosslinked polyethyleneimine (GA-PEI) coating shows a high affinity and selectivity for copper, demonstrating a potential for solving the first step towards such a technology, the uptake. The coatings have shown to efficiently and selectively scavenge large quantities of copper from both artificial and real seawater.^{1, 2}

Any material submerged in seawater will be rapidly conditioned by a polysaccharide film. Copper binding will compete with organic ligands which may limit the performance of the coatings. In this study, the effect of adsorbed seawater-relevant polysaccharides (i.e., carrageenan, sodium alginate, agarose and competing ligand EDTA) on copper binding performance of our polymer films was investigated in an artificial-seawater model system.³ Advanced analytical techniques were used, including grazing incidence X-ray absorption near edge spectroscopy, Time-of-flight secondary ion mass spectroscopy, X-ray photoelectron spectroscopy and quartz crystal microbalance with dissipation monitoring. Results revealed that in seawater a swollen polysaccharide layer allowed unhindered transport of copper into the PEI layer. Our coating outcompeted EDTA, and the spatial distribution of copper species was determined with nanometer precision. The results are highly relevant for copper extraction at low concentrations in complex natural environments as well as strongly suggest the further development of GA-PEI coatings towards advanced marine applications.

Keywords: Characterization of polymers, Copper-chelation, Environmental remediation, polyethyleneimine

1. J. B. Lindén, M. Larsson, B. R. Coad, W. M. Skinner and M. Nydén, RSC Advances, 2014, 4, 25063-25066.
2. J. B. Lindén, M. Larsson, S. Kaur, W. M. Skinner, S. J. Miklavcic, T. Nann, I. M. Kempson and M. Nydén, RSC Advances, 2015, 5, 51883-51890.
3. S. Kaur, I. M. Kempson, J. B. Lindén, M. Larsson and M. Nydén, Biofouling, 2017, 1-11.

Microorganism-based biocatalytical platforms aim at providing domains such as environmental remediation, pharmaceutics synthesis, energy production and sensing with radically new, sustainable approaches^[1]. From microencapsulation to inkjet printing technology, a wide range of approaches have been proposed to address the need to formulate the next generation of biopolymer-based cellularized materials^[2].
Here we will present recent results in the application of freeze casting, a materials processing technique we have recently adapted to produce metabolically active cell-containing materials with controlled morphology^[3,4]
Our approach stands at the interface between standard cryopreservation techniques and commonly used ice templating techniques, providing solid-state cellularized materials with finely controlled macroporous morphology. Using a prokaryote (Pseudomonas aeruginosa) and an eukaryote (Saccharomyces cerevisiae) model microorganisms, we show that ice templating of living cells can be carried out in absence of commonly used cryoprotectants under specific processing conditions in the presence of different polysaccharide hydrocolloids. Moreover we focus on the interplay between the processing conditions, material morphology and cellular viability to discuss the application potential of freeze casting to the elaboration of cellularized materials in bioremediation. The implications of the foam's morphology and stabilization approaches (hybridization vs. ion crosslinking) on their stability in soil, cell viability and bioremediation activity will be discussed in the context of microorganism-based bioremediation of selected organic pollutants in soil and aqueous environments.

[1] S. Christoph, F. M. Fernandes, In Bionanocomposites: Integrating Biological Processes for Bio-inspired Nanotechnologies; Aimé, C.; Coradin, T., Eds.; Wiley, 2017; p. 320.
[2] F. Mano, R. L. Reis, L. Gasperini, J. R. Soc. Interface 2014, 11, 20140817.
[3] S. Christoph, J. Kwiatoszynski, T. Coradin, F. M. Fernandes, Macromol. Biosci. 2016, 16, 182.
[4] S. Christoph, P. Barré, B. Haye, T. Coradin, F. M. Fernandes, submitted 2017.

Microporous polymers are currently being studied for a range of different applications including molecular separation in gas or liquid phase, catalysis, and water treatment. Their porosities are related to highly crosslinked structures or inherently large free volumes. These polymers can exhibit large or even very large surface areas and micropore or mesopore volumes, where micropores are < 2 nm and mesopores between 2-50 nm.
We present findings on micro- and mesoporous polymers designed to separate CO₂ from gas mixtures with either physisorption or chemisorption. Separation of CO₂ is important in Carbon Capture and Storage (CCS) as well as in biogas or natural gas upgrading. Possibilities to tune the microporosity and mesoporosity with chemical methods and means to modify them with aliphatic amines will be highlighted. Such aliphatic amines are shown to act as chemisorbents with high heats of adsorption of CO₂ (Qst) and are relevant to capturing CO₂ from streams with low concentrations of CO₂. Physisorbents, with their comparably low Qst, are more relevant to CO₂ separation when the gas mixture has a high concentration of CO₂. Open questions concerning the price of the polymers and potential advantages as compared with other types of adsorbents, or membranes, will be discussed.
In addition, recent findings on porous polymers derived from platform molecules of biorefineries will be presented. The platform molecules were polymerized, very rapidly, at close to ambient temperatures, and the formed solids/polymers had specific surface areas with values close to 1000 m²/g. One such composition displayed a surprisingly high Qst value of 42-44 kJ/mol, which is important for the CO₂-over-N₂/CH₄ selectivity.

The endocrine disrupting substances (EDCs) can block hormones by binding to receptors inside the cell. It causes endocrine disorders by altering the function of the endocrine system and consequently causes adverse health effects in an organism or its progeny. As a result, it triggers the following problems, cancers, tumors and lesions, reproductive inhibition or failure, suppression of immune system, disruption of endocrine (hormonal) system. With its wide application, EDCs are widely detected in the environment and constantly threatening human health. Therefore, EDCs detection and removal is an important. In this study, we demonstrate a system composed of a composite structure of MoS₂ nanoflake integrated with PNIPAM hydrogel for the detection of EDCs. Functionalization of the MoS2 nanoflake improves bonding with the hydrogel and bonding with the EDC. These bonds increase the Young's modulus of the hydrogel, so that the equilibrium volume of the hydrogel becomes smaller and the hydrogel shrinks. The adsorption mechanism was discussed with a hydrogel elastic modulus in equilibrium. We confirmed that it can be a good alternative for conventional methods by making a simple sensor. Our system is advantageous compared to conventional methods. Since this strategy enables the simple, one-step, easy to detect, we expect that this platform can serve as an aid or substitute of current time-consuming, high-cost, and laborious water pollution monitoring process.

The past decade has witnessed considerable efforts of scientists in addressing challenges in the fields of energy, sustainable development, clean water and healthy life, and tremendous materials with specific features and advanced applications have been developed. Porous
polyelectrolytes, as one of these powerful multifunctional materials platforms, have exhibited the unique strength in solving concerning topics, e.g., sustainability and environmental detection.1 As one subclass of porous polyelectrolyte, porous poly(ionic liquid)s (PILs) membranes have attracted increasing interest among polymer and materials field owing to their typical applications in sensing, actuation, carbon precursors, etc.2,3 However, the exploration of the limitation and interesting application scenarios of such porous materials are
still appealing. Recently our group developed a novel poly(ionic liquid)s--poly(1,2,4-triazolium) PILs.4,5 After the synthesis of poly(1,2,4-triazolium)s via straightforward free radical polymerization, the metal ion loading of such polymers were tested. It is proved that, owing to a possible carbene intermediate process, metal clusters down to the size of 1 nm can be stabilized by poly(1,2,4-triazolium)s in organic solutions.6 Inspired by this carbene chemistry, we designed and developed a 1,2,4-triazolium-based porous polycarbene-bearing membrane. This free-standing nanoporous polycarbene-bearing membrane can serves as an actuator sensor to detect acetic acid (CH3COOH) down to ~ 3.7 ppm in aqueous media, and could in-situ monitor an entire proton-involved chemical reaction event, indicative of their futuristic
real-life application in reaction technology.
(1) Zhang, W.; Zhao, Q.; Yuan, J. Porous polyelectrolytes: charge pores for more functionalities. Angewandte Chemie International Edition, DOI:10.1002/anie.201710272 10.1002/anie.201710272, n/a.
(2) Zhao, Q.; Dunlop, J. W. C.; Qiu, X.; Huang, F.; Zhang, Z.; Heyda, J.; Dzubiella, J.; Antonietti, M.; Yuan, J. An instant multi-responsive porous polymer actuator driven by solvent molecule sorption. Nature Communications 2014, 5, 4293.
(3) Qian, W.; Texter, J.; Yan, F. Frontiers in poly(ionic liquid)s: syntheses and applications. Chemical Society Reviews 2017, 46 (4), 1124.
(4) Xue, H.; Gao, H.; Shreeve, J. n. M. Energetic polymer salts from 1-vinyl-1,2,4-triazole derivatives. Journal of Polymer Science Part A: Polymer Chemistry 2008, 46 (7), 2414.
(5) Zhang, W.; Yuan, J. Poly(1-Vinyl-1,2,4-triazolium) Poly(Ionic Liquid)s: Synthesis and the Unique Behavior in Loading Metal Ions. Macromolecular Rapid Communications 2016, 37 (14), 1124.
(6) Sun, J.-K.; Kochovski, Z.; Zhang, W.-Y.; Kirmse, H.; Lu, Y.; Antonietti, M.; Yuan, J. General Synthetic Route toward Highly Dispersed Metal Clusters Enabled

Enzymatic Biofuel cells (EBC) are devices converting chemical energy into electrical energy using enzymes as biocatalysts and glucose/alcohol and oxygen as biofuels. The EBC can offer advantages like low-temperature operation, neutral pH, and specification and can use glucose and oxygen belonging to human body as fuel sources for use as implantable devices. In spite of that, there are still unsolved problems. Slow reaction of the corresponding enzyme molecules is one of the main reasons and the problem can be alleviated by embedment of mediator into the biocatalyst because the mediator promote electron transfer, followed by reaction rate. Regarding the enzyme and mediator immobilization, (i) electrostatic attraction and (ii) chemical bonding can be considered. For the purpose, in anode, glucose oxidase (GOx) enzyme and dye mediator are used as the biocatalyst while in cathode, GOx enzyme and iron containing porphyrin mediator (linker) are used. With the adoption of GOx enzyme and mediators, the catalytic activity of the biocatalysts and EBC performance are improved. With the results, we believe that this study will contribute to establish standard protocols for improvements in performance of EBC system.

Piezoelectric self-charging cells (SCC) have attracted much interest due to their capability to store piezoelectrically generated energy without a rectification circuit element. In this respect, several approaches have been made to improve the self-charging performance by using ferroelectric nanoparticles and polymer films as separators in the SCC structure. However, self-charging performance of the SCC has been hindered by low conversion efficiency of these devices for practical applications.

Herein, we report a high performance SCC with carbon nanotube (CNT) coated electrodes, realized by employing the ferroelectric poly (vinylidenefluoride-co-trifluoroethylene) P(VDF-TrFE) as a separator in the supercapacitor structure. To effectively charge the SCC, the key requirements are to generate sufficient piezoelectric potential using a ferroelectric separator and to design the electrodes that can store charges separated by piezoelectric potential. To this end, we optimized the supercapacitor structure by adjusting electrode design by spray-coating CNT on Au/polyethylene terephthalate (PET) substrate and the thickness of PVDF-TrFE separator layer. Under the applied force of 0.3 MPa, the SCC fabricated using this approach demonstrates fast charging performance by comparison to other previously reported SCCs, charging up to 1V at relatively short period time. In addition, the based SCC can work as a self-powered strain sensor, effectively detecting different strains without an external power source by the piezoionic effect. The approach used here is simple, effective, and suitable to develope high performance self-charging cell and its potential as a self-powered sensor device.

Acknowledgement: This subject is supported by Korea Ministry of Environment(MOE) as Advanced Technology Program for Environmental Industry Program.

Triboelectric nanogenerators (TENGs) have been highlighted as a power source for small electronic devices thanks to their relatively simple fabrication and integration with existing device structures. To increase their output power to a level sufficient for small electronic device, considerable efforts have focused on improving their output power. So far, different surface patterning methods, dielectric constant tuning, and device structures have been employed. However, these approaches are relatively complicate and the performance of TENGs is still limited by intrinsic properties of materials used.

In this work, we introduce a simple and effective way to tune the triboelectric charging sequence by adopting atomic level chemical surface functionalization. To this end, the synthetic halogenated (Cl, F, and Br)-molecules were functionalized onto polyethylene terephthalates (PETs) to render negative charging surface. For the triboelectrically positive side, on the other hand, the surfaces of PETs were functionalized using several aminated-molecules. Using Kelvin probe microscopy, electrometer, and density functional calculation, thorough investigation has been made to understand the charging behavior of functionalized surfaces. Our results show that wide spectrum of triboelectric charging can be clearly formed by the proposed methods. Noticeably, the TENGs with functionalized using the pair (Cl-PET:PEI(b)-PET) exceed the output voltage of ~520 V and current density of ~110 mA/m²_, corresponding power density of ~55 W/m², which is one of the highest values reported to date. Besides, by providing wide choices of surface functionalization, friction surface can be rendered to have different triboelectric properties, allowing to adopt this technique to develop triboelectric sensors. This works introduced the simple chemical surface method, which can be adopted for developing energy harvesting devices and sensors based on the triboelectric effect.

Triboelectric nanogenerators (TENGs) have gained much attention thanks to relatively high output power generation by scavenging various resources such as wind, sound, vibrations, and any physical movement existing in our living environment. In particular, vibration and noise are persistent resources where we can harvest energy. For these resources, most of energy harvesting methods reported to date utilize piezoelectric ceramic materials and harmonic oscillation at the resonant frequency. However, the resonance frequency required for energy harvesting is considerably higher than the level existing in typical factory environment or living environment. Besides, output power level is not sufficient for providing power to electronic devices.

To overcome this limitation in this work, we develop tribeoelectric energy harvesting device that can harvest noise and vibration existing in factory or living environment by designing hybrid device exploiting both piezoelectric and triboelectric generation schemes in a single device structure. Using this approach, the greatly enhanced output power is achieved by dual power generation of hybrid device structure. In the PENG part, electrospun poly (vinylidenefluoride-co-trifluoroethylene) P(VDF-TrFE) nanofiber was sandwiched between Al electrodes as a vibrating membrane. In the TENG part, on the other hand, imprinted micro-pyramid pattern surface was contacted with the PENG’s Al electrode. Thanks to coupling effect between triboelectric charge and piezoelectric charge, greatly enhanced output power was generated, comparable to that of TENG. Under the sound wave of 90 dB at 100 Hz, typical value that exist in factory environment, the integrated output power density of hybrid device exceeded ~3 mW/cm². The approach introduced here can provide a route to harvest low frequency vibration and sound energy harvesting.


Acknowledgement: This subject is supported by Korea Ministry of Environment(MOE) as Advanced Technology Program for Environmental Industry Program.

Exploiting exchangeable covalent bonds as dynamic cross-links affords a new class of polymer materials coined as vitrimers. These permanent networks are insoluble and infusible but the network topology can be reshuffled at high temperatures, thus enabling glass-like plastic deformation and reprocessing without depolymerization. We have developed functional and high-value ion conducting vitrimers that take inspiration from poly(ionic liquid)s which are unique polyelectrolytes with cationic and anionic groups included in the repeating unit. Tunable networks with high ionic content are obtained by the solvent- and catalyst-free polymerization of an α-azide-ω-alkyne monomer and concomitant quaternization of the resulting poly(1,2,3-triazole)s with a series of difunctional cross-linkers (Figure 1). Temperature-induced transalkylation exchanges between 1,2,3-triazolium cross-links and halide-functionalized dangling chains enable to recycle and reprocess these highly cross-linked permanent networks. These vitrimers can also be recycled by depolymerization with specific solvents able to displace the transalkylation equilibrium, and display a great potential for applications that require solid electrolytes with excellent mechanical performances and facile processing such as supercapacitors, batteries, fuel cells and perm-selective membranes.

Nanofiber extraction using the electrospinning method has gained attention as a route to obtain nanofiber textiles and membranes using synthetic and natural polymers. There exist numerous potential applications such as smart textiles, sensors, battery separators, and filters by adopting the electrospinned nanofibers. Recently, electrospun nanofiber have also gained interest as air filter materials. Due to its exceptional dust trapping capability, it can be used to produce compact and high efficient air filter media. In particular, particulate matter (PM) below 2.5 is especially difficult to trap with typically filter media.
In this work, we report the light transmittable air filter formation by using the electrospinning method. We employed different polymers such as polyarylonitrile (PAN), polyimide (PI) resin, and Nylon-6 to determine optimal nanofiber formation condition to btain nanofiber uniform films on different mesh substrates. Using differently electrospinned nanofiber mats, the visibility, uniformity, and individual fiber thickness of the prepared films were examined and determined optimal conditions. Using these filters, we also performed PM trapping test and compared the trapping efficiency between the filters prepared by electrospinning method. Specifically, we also tested the filtering efficiency by varying light transmission level. The results indicate close relationship between the electric dipole moment of the polymer source and PM trapping efficiency.

Acknowledgement: “This subject is supported by Korea Ministry of Environment(MOE) as "Advanced Technology Program for Environmental Industry Program".

Triboelectric energy harvesting device, so called triboelectric generator (TEG), generates electricity by repeated friction of two surfaces with different triboelectric properties. Thanks to its relatively high output power and simple device fabrication process, this energy harvesting scheme has been actively investigated as a power source for small electronic devices or wireless sensors. Until now, persistent efforts have been focused on how to increase the output power of the TENGs. In particular, modulation of dielectric permittivity of the friction surface have been demonstrated as one of the facile methods to effectively boost the output power of TENGs.

In this work, we report the performance of TENG realized by electrospun nanofibers on the friction surface. Different polymers were electrospun on the electrode substrate, such that one surface is coated with triboelectrically positive nanofibers and the other is coated with triboelectrically negative ones. In particular, by forming core-shell nanofiber on the one of the contact surface, where the core contains a polymer with high dielectric permittivity and the shell is coated with triboelectrically opposite one compared with the opposing friction surface, the performance of TENG was greatly enhanced. Furthermore, the nanofiber formation on the friction surface also increases the surface area of the friction surface, effective increasing surface charge density, resulting in high current density and voltage. The method introduced here can be potentially adopted for developing textile based energy harvesting utilizing triboelectric effect.

Rapid diagnosis of foot-and-mouth disease virus (FMDV) is significant for the prevention of the FMD outbreak. In this study, we developed polyvinylidene difluoride (PVDF) supported polydiacetylene (PDA) immunosensor to detect FMDV, where VP1 polyclonal antibody was directly conjugated as a virus binding module without linker length. The optimal constituent ratio of the key platform was determined as 10,12-pentacosadiynoyl VP1 polyclonal antibody: dimyristoyl phosphatidyl choline: 10,12-pentacosadiynoic acid 1:4:5. With this composition, photo-polymerized colloids were investigated, and PVDF solid-state sensing was evaluated for the easy and portable platform. The detailed analyses were performed using UV-vis spectroscopy, DLS, FT-IR, TEM, and SEM. Resultingly, the blue-to-red color transition and fluorescent signal were successfully observed in the presence of FMDV antigen. This work provides a rapid and simple methodology for the FMDV detection.

Although nacre (mother of pearl) is composed of mostly brittle aragonite (CaCO3) nanoplatelets and little amount of biopolymers, it shows superior mechanical properties like tensile strength and fracture toughness because of its hierarchical brick-and-mortar structures from molecular to macro levels. In this research, we extracted cellulose nanofiber from tunicate and fabricated bio-friendly composites, montmorillonite (MMT)-cellulose nanofiber (CNF) nanocomposites, by a simple filtration process to mimic nacre structure for enhancing its mechanical performances. We optimized the properties of MMT/CNF composites by varying MMT/CNF ratio, which was characterized by a scanning electron microscope (SEM), an X-ray diffraction (XRD), and a Fourier transform infrared spectroscopy (FT-IR). Also, relatively high toughness and strength were obtained by measuring in a tensile tester. These results suggest that our bio-friendly MMT-CNF composites have a potential replacement of commercial polymers.

Arabinoxylans (AX) are non-starch polysaccharides from the cell walls of grains. AX are constituted of a linear backbone of xylose units with arabinose substituents and some ferulic acid esterified to arabinose. AX can form gels by oxidative coupling of the phenoxy radicals resulting from the oxidation of ferulic acid. Most bioethanol plants use maize as their main ingredient and the growth of this industry has provided an abundance of co-products such as the dried distillers grains with solubles (DDGS), which can be a source of AX. AX gels are of great interest as controlled release matrices in food, medicine, agronomy and cosmetic industry, among others. In the present study, AX were alkali extracted from DDGS, characterized and gelled and the gel rheological properties and microstructure were investigated. The yield of AX was 4 % (w/w dry basis). These AX presented an arabinose to xylose ratio of 0.61, a ferulic acid content of 0.54 µg/mg AX and a Fourier Transform Infra-Red (FT-IR) spectrum typical of this polysaccharide. AX solution at 2% (w/v) formed gels induced by a laccase as cross-linking agent. Cured AX gels registered storage (G’) and loss (G’’) moduli values of 77 and 0.2 Pa, respectively and a diferulic acid content of 0.20 µg/mg AX. Scanning electron microscopy analysis of the lyophilized AX gel showed that this material resembles that of an imperfect honeycomb. The understanding of DDGS AX yield and characteristics can be useful to propose alternative uses of this co-product. These AX gels could be used as microencapsulation systems for bioactive compounds or cells.

Ferulated arabinoxylans (AX) are polysaccharides that form hydrogels by covalent cross-linking involving FA oxidation. AX gelation process and gel properties depend on AX structural characteristics such as molecular weight, substitution degree, and FA content and location. AX gels have potential application as delivery systems for biomolecules or cells and antioxidant activity. AX modification can be a path to tailor their properties and specific applications. Only a few reports have been carried out on the carboxymethylation of AX. The influence of carboxymethylation on the gelling capacity, rheological properties, and antioxidant activity of AX from different sources was investigated. Wheat flour arabinoxylan (AX1) and distillers dried grains arabinoxylan (AX2) were carboxymethylated. The success of the treatment was corroborated by Fourier-transform infrared spectroscopy. Unlike non-modified AX, the spectra of carboxymethylated AX1 (CAX1) and AX2 (CAX2) showed three new bands at 1594, 1418 and 1324 cm^-1. The absorption bands at 1594 and 1418 cm^-1 were assigned to C=O stretching of the COO^- ion, indicating the presence of new carbonyl groups within the carboxymethylated species. Meanwhile, the absorption band at 1324 cm^-1 was assigned to C=O stretching of the –COO^- ion or to the symmetric angular deformation of the C-H bond. Size-exclusion chromatography analysis showed that the average molecular weight (Mw) of the samples was affected by the carboxymethylation. The Mw for CAX1 decreased from 729 to 591 kDa, while that the Mw for CAX2 increased from 130 to 145 kDa. These results indicate that the chains of CAX1 were susceptible to degradation while that CAX2 were not. In addition, it is possible to assume that the increase of Mw in CAX2 involves the introduction of new carboxymethyl groups. The rheological measurements demonstrated that AX1 and AX2 solutions formed gels. The storage modulus for AX1 gel was lower (G’= 71 Pa) than for AX2 gel (G’= 196 Pa), which could be attributed to a lower FA content in AX1 in relation to AX2. In contrast, the CAX1 and CAX2 do not gel (G’ < G’’); the release of FA from AX chains during carboxymethylation process could explain this result. The antioxidant activity of AX1, CAX1, AX2 and CAX2 were of 135 ± 17, 249 ± 7, 229 ± 10 and 283 ± 4 TEAC (mmol/ kg), respectively. The increase in the antioxidant activity of CAX1 and CAX2 in relation to the unmodified molecules could be related to the carboxymethyl groups incorporation, which increases the electronic cloud in the AX chains favoring the potential for hydrogen donation. Based on these results, the carboxymethylation of AX decrease its gelling capacity but increase its antioxidant activity, which could define the possible applications of these carboxymethylated materials in food, cosmetics, and biomedicine, among others areas.

Conductive polymers are used in a variety of systems due to their electrochemical stability and inherent conductivity. Poly(3,4-ethylenedioxythiophene) (PEDOT) is synthesized through a micellar dispersion that allows the incorporation of biomolecules, which are useful in an wide range of applications, such as chemical detection, pharmaceutical, biomedical, and environmental. κ-carrageenan (κc) has been used for immobilization of microorganisms and as a biosurfactant. In this work, we have studied its doping effect in a conductive matrix. A PEDOT/κc system was obtained by electrodeposition, and its properties were compared to a standard surfactant, sodium dodecyl sulfate (SDS). The electrochemical characterization was performed to evaluate the stability and residual activity after polarization between -0.3 V and 0.9 V at a scan rate of 100 mV s^-1 in aqueous solutions containing KClO₄ as electrolyte. The oxidation level of the samples was studied using Raman Spectroscopy. It was shown that the reduced structure of PEDOT/SDS decreased after polarization, however the PEDOT/ κc system demonstrated a satisfactory behavior as doping agent during the analysis. Electrochemical activity remains constant after 150 cycles for the biopolymer system (PEDOT/κc) meanwhile it decreased for the standard PEDOT/SDS system. These results aim to use this conductive biopolymer system to incorporate biomolecules for multiple applications.

The significance of protein aggregation has been extensively studied in biomedical and food research. While biomaterials derived from plant proteins, such as soy protein, as green material alternatives, have gained enormous attentions in various industrial and engineering fields including food packaging and adhesives, etc., the roles of protein aggregation in material properties and functionalities are still insufficiently understood, which will be the main focus of this study.
In this study, soy protein isolate (SPI) with different aggregated structures, was investigated as a functional modifier to tune the microstructures, ferroelectric properties and dielectric properties of two polymers: hydrophobic poly(vinylidene fluoride) (PVDF) and hydrophilic poly(ethylene oxide) (PEO). The aggregated structures of SPIs were obtained via various controlled denaturation and modification processes, including heat treatment, high-energy sonication, tuning pH values, and usage of denaturation agents. Denatured SPIs were then applied to polymer matrices. It was found that SPI aggregation and SPI-polymer interactions were strongly subjected to the denaturation conditions, as well as properties of polymer matrix, which led to distinctive morphologies and structures of the resulting polymer/SPI films, investigated via scanning electron microscope, confocal laser scanning microscopy, X-ray diffraction spectrum and Fourier transform infrared spectroscopy. The changes in microstructures consequently caused the variation of ferroelectric and dielectric properties of the films, leading to different dielectric polarization and energy storage properties. The energy storage performances of the polymer/SPI films in this study were sensitive to the denaturation conditions of SPI, due to altered SPI aggregation and distinctive SPI-polymer interactions. Regardless of polymer matrices, it was found that high temperature heat denaturation of SPI accounted for the most desirable dielectric energy storage performances with high released energy density and high energy storage efficiency. Meanwhile, the polymer matrix also plays an important role. While the highest polarization was achieved in PVDF/SPI films via high energy sonication denaturation of SPI, the SPI denatured by sonication was responsible for the lowest dielectric polarization in PEO/SPI films, suggesting the importance of polymer matrix in SPI aggregation and SPI-polymer interactions.

Nacre consists of 95% of brittle calcium carbonate platelets and 5% of ductile biopolymer. Due to organic-inorganic components structured like a “brick-and-mortar”, the composite shows exceptional mechanical properties such as remarkably high fracture toughness and tensile strength. Because of these properties, nacre-mimetics hold great potentials for high mechanical performance and functional materials. In the presentation, we have fabricated nacre-like nanocomposites via vacuum filtration of montmorillonite (MMT) and cellulose nanofibers (CNFs) mixture. Although the composite exhibited higher strength and toughness than pure MMT and CNFs, we tried to improve the mechanical property by changing it into the ternary system. Polymer binders were further introduced to improve mechanical property of the composites. We compare nanostructures, chemical characteristics, and mechanical properties of the composites systematically.

Billions of metric tonnes of cellulosic biomass products such as corn stover, sugarcane bagasse and switchgrass are produced yearly and are often used for biofuel production, animal feed or for other energy needs. By implementing aqueous pretreatment via oxidative digestion, sol-gel polymerization with Fe3+ ions and a heat treatment process the carbohydrates obtained from these materials can also be transformed into a porous metal-carbon network with superhydrophobic properties and magnetic attraction. Carbohydrate precursor materials are all abundant and cheap making them ideal for practical, scalable oil cleanup and numerous other marine applications and are composed of biologically innocuous components in their final form. These oil-absorbing materials were structurally and compositionally characterized using FTIR, Raman, EDXA, XRD, SEM and HRTEM. Materials were found to be able to absorb 2-4X their weight in nonpolar materials, were able to carry this nonpolar material while being manipulated with a magnet and showed superhydrophobicity (contact angle > 150 degrees).

Mining from the ores is never cent percent, and the remains are rejected to tailings. These tailings are often rich in precious metals ions such as copper and acidic constituents which when let out contaminate freshwaters such as lakes, rivers, streams, and groundwater. Porous ion exchange resins with attributes of the high surface area, fast adsorption kinetics and selectivity are attractive for recovering metals like copper and adding value to the mining process.
From our previous studies, we already know that glutaraldehyde crosslinked polyethyleneimine (GA-PEI) has an excellent selectivity and affinity for copper.^1-3 Here, we modified an inexpensive biotemplate, i.e., diatomaceous earth particles (DE) with GA-PEI⁴ and performed subsequent alkaline etching of the template to synthesize porous GA-PEI resin. The cross-section of GA-PEI modified single DE frustule was examined through focused ion beam scanning electron microscopy (FIB-SEM) and copper distribution through the whole volume of frustule was investigated using energy dispersive X-ray spectroscopy (EDX). GA-PEI resins produced after etching of the DE template were characterized for structure and morphology through scanning electron microscopy (SEM) as well as composition through X-ray photoelectron spectroscopy (XPS). The kinetics of copper ion adsorption was determined to be fast with resins achieving 75% saturation of adsorption sites in just 15 minutes, and binding capacity was evaluated through Langmuir adsorption isotherm. We also investigated the copper uptake of GA-PEI resin from its high concentration environmental solutions such as acid mine drainage from Mt Lyell in Tasmania. The results revealed that copper could be efficiently and selectively bound at pH 4 and completely eluted at pH 1. The copper recovery and regeneration capability of the GA-PEI resin was evaluated in two cycles of iteration and performance compared to two commercial resins, Purolite S930 Plus and Lewatit TP220. The results implicate great potential for using GA-PEI resins for effective recycling copper from highly copper polluted environmental solutions.

1. J. B. Lindén, M. Larsson, B. R. Coad, W. M. Skinner and M. Nydén, RSC Advances, 2014, 4, 25063-25066.
2. J. B. Lindén, M. Larsson, S. Kaur, W. M. Skinner, S. J. Miklavcic, T. Nann, I. M. Kempson and M. Nydén, RSC Advances, 2015, 5, 51883-51890.
3. S. Kaur, I. M. Kempson, J. B. Lindén, M. Larsson and M. Nydén, Biofouling, 2017, 1-11.
4. A. Nosrati, M. Larsson, J. B. Lindén, Z. Zihao, J. Addai-Mensah and M. Nydén, International Journal of Mineral Processing, 2017, 166, 29-36.

Biopolymers, like DNA, peptides, and polysaccharides, are well-known to form liquid crystalline phases, primarily with a nematic or chiral nematic structure.(1) In this work we show how the packing of cellulose nanocrystals (CNC) in the anisotropic chiral nematic phase appears as investigated over a wide concentration range by small-angle X-ray scattering (SAXS) and laser diffraction. The average separation distance between the CNCs and the average pitch of the chiral nematic phase were been determined over the entire isotropic–anisotropic biphasic region. The dependence of the twisting on the volume fraction was related to the increase in the magnitude of the repulsive interactions between the charged rods as the average separation distance decreases.(2) We will also present work the alignment of CNC in a suspension of CNC and lepidocrocite (Lp) nanoparticles using an external magnetic field. The details of the CNCs-Lp liquid crystalline phase were studied by Small Angle Neutron Scattering where contrast matching was been used to study the magnetic response of each component in the CNCs-Lp composite.

1. Hamley, I. W. Liquid Crystal Phase Formation by Biopolymers Soft Matter 2010, 6, 1863
2. C. Schütz, M. Agthe, A. B. Fall, K. Gordeyeva, V. Guccini, M. Salajková, T. S. Plivelic, J. P. F. Lagerwall, G. Salazar-Alvarez and L. Bergström, Langmuir, 2015, 31, 6507.

One of the grand challenges facing humanity today is access to sustainable materials and chemicals which are at the heart of renwable energy technologies. The production of materials, chemicals and fuels from abundant and renewable resources will eliminate our dependence on petroleum/critical metal based supplies and will provide access to a new economy based on available reserves.
While carbon is widespread on Earth, it has been mainly synthesised from fossil fuel based precursors with sophisticated and energy consuming methodologies that generate toxic gases and chemicals. We have demonstrated that it is possible to mimicking the natural process of carbon formation and prepare carbon nanomaterials from biomass using mild hydrothermal processes.
In this talk I will present some of the fundamentals governing the production of such carbon nanomaterials. We will also discuss the application of HTC materials in electrocatalytic reactions such as Oxygen Reduction Reaction and Oxygen Evolution Reaction¹ as well as electrodes in Na-ion² and Li-s batteries.³

Tang C, Wang HF, Chen X, Li BQ, Hou TZ, Zhang B, Zhang Q, Titirici MM Wei F Advanced Materials, 2016 vol. 28, (32) 7030-7030.
Li Y, Hu YS, Titirici MM, Chen L and Huang XAdvanced Energy Materials, 2016, 6, (18)
Rybarczyk MK, Peng HJ, Tang C, Lieder M, Zhang Q and Titirici MMGreen Chemistry, 2016, 18, (19) 5169-5179

Cellulose and lignin are two of the key-biopolymer components from the forest. Combining derivatives of those with additional redox systems and conductors, large-scale batteries and supercapacitors have been realized. Cellulose provides desired structure, at the nano-, meso- and macro-dimensions, and ligninsulphonate provide oxidation reaction. Adding reduction reaction, delivered from bio-pigments, with electronic conductors and electrolytes, an all-organic battery and supercapacitor technology has been developed. Large-volume manufacturing processing is currently being developed to realize a large-scale electrical energy storage technology for the grid, to achieve peak shaving and to balance supply and demand of electricity in our society. The production protocol includes classical paper-making, lamination and printing technologies.

Eumelanin, a brown-black pigment ubiquitous in fauna and flora, can be synthesized by the oxidative polymerization of 5,6-dihydroxyindole (DHI) and/or 5,6-dihydroxyindole-2 carboxylic acid (DHICA). This redox-active pigment features interesting functional properties, such as photoprotection, antioxidant behavior, hydration dependent conductivity, metal binding affinity and free radical scavenging [1][2]. Furthermore, eumelanin features broadband visible light absorption.
Photoconductivity experiments of melanin are available in the literature [3]. Melanin-based electrodes for supercapacitors and batteries have been demonstrated by our and other groups [4][5]. Here we report on the possibility to enhance the storage properties of the biopigment by photoinduced charging, in parallel to electrical charging. In our study, we used chemically controlled melanin, obtained by solid-state polymerization of the DHI and DHICA building blocks (to give respectively polyDHI and polyDHICA). Controlling the (supra)molecular structure of eumelanin is imperative to gain insight on its (photo)storage properties and to fully exploit its technological potential. Indeed, due to the limited processability of eumelanin, fundamental aspects related to the effect of the (supra)molecular structure on the optical and redox properties of the pigment are largely undiscovered.
We studied the electrochemical behavior of DHI- and DHICA-melanin as well as Sepia melanin (extracted from sac of cuttlefish) loaded on carbon paper as electrodes, under dark and light (1 sun) conditions. The samples were investigated by cyclic voltammetry in aqueous acetate electrolytes pH=5. Higher (photo)currents were observed for DHI-melanin, likely due to a better pi-pi stacking with respect to DHICA-melanin [2].
Considering the optical properties of eumelanin, our work contributes to advance the development of biologically derived all organic solar supercapacitors batteries, integrating the solar conversion and the energy storage functions.

[1] E. Di Mauro, R. Xu, et al., MRS Communications (2017).
[2] R. Xu, E. Di Mauro, et al., APL Materials (2017) (under revision).
[3] a) Mostert, A. B., Powell, B. J., et al. Proceedings of the National Academy of Sciences 109((2012). b) Abbas, M., D’Amico, F., et al. Eur. Phys. J. E. 28.3 (2009).
[4] P. Kumar, E. Di Mauro, S. Zhang, A. Pezzella, F. Soavi, C. Santato, F. Cicoira, J. Mater. Chem. C. 4, 9516 (2016).
[5] Y.J. Kim, W. Wu, S.-E. Chun, J.F. Whitacre, C.J. Bettinger, Adv. Mater. 26, 6572 (2014).

Supercapacitors are becoming essential energy storage devices for applications that require long lifetime and high power delivery over a short time (consumer electronics, transport, biomedical equipment, etc.). To enhance the performance of a supercapacitor it is preferential to use carbon electrode materials with both hierarchical porosity and good electrical conductivity. Hierarchically organized meso- and microporosity provides a large uptake, diffusion and attraction of mobile electrolyte ions to an electrode surface, while high conductivity is necessary for rapid power output in a supercapacitor device.
Biomass-derived nanocarbons can satisfy these requirements. Moreover, they are sustainable and cost-effective for large-scale industrial production, and that is why they should be accounted as a vast and sustainable alternative for the commonly produced carbon materials. In this study, we fabricated electrodes from composite precursors which consist of two different cellulose types: 1) electrospun cellulose (EC) obtained via a bottom-up approach, and 2) nanofibrillated cellulose (NFC) obtained via a top-down approach. Freeze-dried composite EC/NFC sheets were placed between two silicon wafers into a quartz tube furnace with inert N₂ flow to obtain the final nanocarbon structure. Temperature was raised with a rate of 5 °C/min up to 800 °C and was kept for 30 min. The resulting freestanding carbon nanofibrous (CNF) sheets are composed of both hierarchical size of fibers (from few nm to 150 nm in diameter) for higher accessible surface area and hierarchical porosity for effective electrolyte diffusion and adsorption. The sheets have the controlled thickness range of 10-50 μm, the surface area of up to 500 m² g^-1 and at the same time rather high electrical conductivity of ≈ 1 S cm^-1. High electrical conductivity should be attributed to the conductive CNF backbone evolving from EC part of the precursor.
Finally, electrodes of the desired diameter were pressed out with a punch and evaluated in a symmetrical two-electrode cell. The electrochemical cell contained composite carbons as working electrodes, glass fiber mat as a separator, and 6 M aqueous solution of KOH as an electrolyte. The composite CNF electrodes demonstrated good electrical double layer capacitive behavior represented by moderately rectangular shape of CV curves. In addition, they were characterized by good aerial capacitance (127 mF cm^-2 at 5 mV s^-1) and cyclic stability (90% of the initial capacitance remaining after 5000 charge-discharge cycles). The results show vast potential benefits from using such cellulose-derived carbon nanomaterials in supercapacitors.

Here, we present a strategy for the design of polymers for battery electrodes where we combine separately optimized structures for the backbone and side chains of conjugated polymers to achieve efficient mixed electronic and ionic conduction. We consider conjugated polymers with a low ionization potential or large electron affinity to address specifications for both cathode and anode materials with redox potentials which fit well with the allowed electrochemical window for water. After identifying suitable organic semiconductors which can be reversibly be charged and discharged in aqueous solutions, we studied the role of the side chain on the electrochemical redox reactions. Polar side chains were attached at the backbone to increase ion conduction to allow for a reversible and fast charging and discharging of the materials in pH neutral sodium chloride water based electrolytes. A similar strategy has previously been successfully applied to the design of polymers for organic electrochemical transistors for bioelectronics.¹ Here, we show how the specific capacity of these materials, when used as electrodes, can be further improved through side chain engineering. We demonstrate the fabrication of battery devices with a water based electrolyte using p and n-type conjugated polymers as the cathode and the anode. The device shows promising stability, charging rate and can be operated under a nearly unipolar potential window of 1.4 V.

1. A. Giovannitti, C. B. Nielsen, D.-T. Sbircea, S. Inal, M. Donahue, M. R. Niazi, D. A. Hanifi, A. Amassian, G. G. Malliaras, J. Rivnay, and I. McCulloch, Nat. Commun., 2016, 7, 13066.

Both catalyst immobilization and use of environmentally benign solvents are paramount for the development of sustainable catalytic processes. In recent years, we have devised modular synthetic strategies polymer-supported N-Heterocyclic carbenes (NHCs) to catalyze benchmark reactions of molecular organic and organometallic chemistry (e.g. benzoin condensation, transesterification, or the Suzuki and the Heck cross-coupling reactions). For this purpose, imidazolium-based (co)poly(ionic liquid)s (coPILs) featuring non-innocent counter-ions, such as acetate or hydrogen carbonate, have been specifically synthesized. This has been achieved either by free-radical polymerization (FRP) or by controlled radical polymerization proceeding by the reversible addition fragmentation chain transfer (RAFT) process. The organic and basic anions can eventually interact with the C2-proton of imidazolium units to in situ generate (co)polymer-supported NHCs. Different air-stable, recyclable and thermally switchable styrenic-type coPIL precursors have thus been rationally designed, including:

i) statistical coPILs made by FRP,^[1,2]
ii) single chain nanoparticles (SCNPs) with imidazolium-type crosslinks obtained by folding of a RAFT-derived parent copolymer bearing antagonist groups,^[3]
iii) star-like core-crosslinked polymeric nanoreactors with supported Pd(II)-NHC₂ catalytic sites inside their core.^[4]

In the latter case, catalytic entities have been segregated into the cross-linked hydrophobic core of star-like polymeric micelles, the hydrophilic shell ensuring water-solubility. A parent diblock copolymer, consisting of a hydrophilic PEO block and a statistical PS-co-poly(4-vinylbenzylethylimidazolium chloride) hydrophobic block, has been first synthesized by RAFT copolymerization. Addition of Pd(OAc)₂ followed by nanoprecipitation in water has driven the metal-ligand coordination core crosslinking reaction, forming robust polymeric micelles with internal Pd(II)-NHC₂ crosslinks. An outstandingly high catalytic activity is observed at low loadings both for the Pd-catalyzed Suzuki and Heck reactions in pure water, in comparison to molecular and non-self-assembled analogues.

References.
[1] P. Coupillaud, J. Vignolle, D. Mecerreyes, D. Taton, Polymer 2014, 55, 3404-3414
[2] R. Lambert, P. Coupillaud, A.-L. Wirotius, J. Vignolle, D. Taton, Macromol. Rapid Commun. 2016, 37, 1143-1149.
[3] R. Lambert, A.-L. Wirotius, D. Taton, ACS Macro Let. 2017, 6, 489-494.
[4] D. Taton et al. Manuscript in preparation.

Fuel cells are considered as the promise of a green and highly efficient power source. Numerous research are focused on proton exchange membrane (PEM) in PEMFC and anion exchange membrane (AEM) in AEMFC for decades. Alkaline anion exchange membrane fuel cells (AEMFCs) attract much attention because they could utilize non-noble metals as catalysts, such as Ni or Ag etc instead of noble platinum catalysts in PEMFC, and exhibited enhanced oxygen reduction kinetics. Composite membranes have shown promising advantages over conventional pure membranes when used as membrane in fuel cells. In this work, the quaternary ammonium modified CD edge functionalized GO were employed as inorganic filler for preparing PPEK composite membrane. Through by self-assembling between PPEK with CD_β@GO, the interfacial compatibility of composite membranes has been improved. The prepared composite membranes exhibited high thermal stability and enhanced mechanical properties. Meanwhile, the 10% QA-CD_β@GO/PPEK membranes exhibited a high hydroxide conductivity of 42.37 mS/cm at 80 Degrees Celsius and alkaline stability in 1 M NaOH solution at 80 Degrees Celsius for 400 h. In addition, the swelling ratio of all the composite membranes QA-CD_β@GO/PPEK were lower than 20%. Furthermore, the results revealed that graphene oxide composite membrane could be used as anion exchange membrane. Further studies were required to enhance the OH^- conductivity of the composite membranes and to change the bond between quaternary ammonium groups and CD for the higher alkaline stability.
In addition, a high molecular weight polybenzimidazole (PBI) AEM with side chain ammonium cations will be presented in this presentation also, which demonstrates highly OH^- conductive and excellent alkaline stability over 1000 h in 1M KOH solution at 80 Degrees Celsius.

Carbon nitride has recently attracted much attention owing to its visible-light-driven hydrogen evolution capability which is first published in 2009.^[1] Compared with 1D-structured melon, which has already been well-studied by other research groups, the melon oligomer and poly (triazine imide) (PTI/Li⁺Cl^-) are two promising structures which show better photocatalytic property. However, there still remain some room for improvements to be done such as increasing the amount of functional groups of carbon nitride, which are known to be active sites during a photocatalytic process. These active sites are regarded as the predominant factor in the carbon nitride series.^[2] Herein, two strategies were applied to modify the PTI & melon oligomer for the purpose of enhancing its photocatalytic ability. The first process is by using isopropanol (IPA) and ethanol in distinct heat treatment to accomplish surface functionalization. Solid NMR, FTIR and EA were used to prove that additional functional groups are successfully linked. Also, the UV-Vis results indicated that the absorption range had a red-shift to a higher wavelength which is due to the change in powder color. For the second process, liquid exfoliation method was used to obtain ultrathin nanosheets in order to enhance its photodegradation ability due to the further increase in surface area and active sites. By considering that the enthalpy of mixing should be minimized, water is considered as the optimal solvent and was applied due to having a similar surface energy to carbon nitride nanosheet.^[3] The BET analysis showed that the surface area increased which brought about more than five times enhancement in its photocatalytic property.

Keywords: carbon nitride, surface functionalization, liquid exfoliation, photocatalyst

REFERENCES
[1] X. Wang, K. Maeda, A. Thomos, K. Takanabe, G. Xin, J. M. Carlsson, K. Domen, M. Antonietti, Nat. Mater., 8 (2009) 76-80
[2] M. K. Bhunia, K. Yamauchi, K. Takanabe, Angew. Chem. Int. Ed., 126 (2014) 11181-11185
[3] K. Schwinghammer, M.B. Mesch, V. Duppel, C. Ziegler, J. Senker, B. V. Lotsch, J. Am. Chem. Soc., 136 (2014) 1730-1733

Rapid development of wearable electronics, accessible and environmentally sustainable energy generation has attracted an extensive attention in next generations. In spite of flexible piezoelectric nanogenerator (PNG) based on electrospun poly(vinylidine fluoride) (PVDF) nanofibers (NFs) having light weight are in great demand, the development of low throughput, electrode compatibility and high durability remains a challenging task in meeting the requirements of wearable electronics devices. Recently conducting electrospun nanofiber has gained immense attention in several researchers due to the rapid growth of technology development with nanofibers, such as sensors, actuators, supercapacitors, energy harvesters (e.g., photovoltaic, piezo-, pyro- and triboelectric nanogenerator). However, the brittleness, toxicity and high cost of inorganic materials have prohibited its use as a conducting electrode, in addition, direct adherence on electrospun nanofibers surface is one of the major challenges to build the permanent electrodes in device structures. In contrast, conducting organic materials are being presented as a viable alternative as an organic electronic devices, particularly if one can achieve adequate coating on the electrospun polymer fibers.
Here, we report a simple design strategy of all organic PNG (AOPNG) based on multilayer assembled PVDF NFs mat where conducting polymer poly (3, 4- ethylenedioxythiphene) (PEDOT) coated PVDF NFs are used as electrodes. The continuous electrospinning technique in combination with vapor phase polymerization (VPP) enables such multilayer structure followed by successive coating of PEDOT. The nanofibers are characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and Field emission scanning electron microscope (FE-SEM) before and after the coating of conducting polymer. The electrical performances were clarified by measuring the current-voltage (I-V) characteristic. Owing to multilayer structure and excellent electrode contact-stability, AOPNG exhibits an effective conversion of mechanical energy of human finger movements into electrical energy. The coating of conducting polymer upon PVDF fiber opens the use of organic electrode in various applications especially for e-skin devices solving the so called electrode issues. Now a day, monitoring of human physiological signals is an effective approach for the assessment of health problems. So, we can monitor our physiological signals such as body temperature, heartbeat rates, acceleration, gravity or motion and so on by the use of such organic sensors. More importantly AOPNG can show ultra-sensitivity towards human movements such as walking, foot strikes. Fatigue test demonstration under continuous mechanical impact (over 6 months) shows great promise as a wearable energy harvester. Thus it will play an essential role in future wearable electronics and healthcare systems.

Pretreatment of lignocellulose to break down the material into monosaccharides has been researched extensively for its potential for biofuel production due to the abundance of lignocellulosic biomass waste. Byproducts of this process can limit the yields of ethanol in bioreactors making other uses of the waste material worth exploring for technologies such as cheap functional polymeric materials. By adjusting these classic aqueous treatment methods and selecting the right metal ions and applying a drying and chemically reductive heat treatment a variety of porous carbohydrate-based polymeric materials were generated for different uses including oil cleanup, sensors and battery materials. These syntheses were studied in situ using UV-vis spectroscopy and strong base titration. Thermogravimetric analysis was used to study the reductive heat treatment step in the synthesis process. The solid structures and composition of generated polymeric materials were studied using FTIR, Raman and EDXA. SEM and HRTEM were used to study the microstructure of the materials. These materials were found to exhibit a variety of properties related to the metals they were produced with and the types of carbohydrates used to make them.

By controlling the interaction of nano-scale building blocks, nature produces highly complex architectures using only biopolymers and self-assembly routes. Inspired by such biological nanostructures [1-2], the possibility to design materials at the nano-scale by guiding the hierarchical self-assembly of its constituent components is an attractive route for rationally-designed, sustainable manufacturing of optical material [3-6]. Within the large variety of biological building blocks, polysaccharides are between the most promising bio-sourced materials, primarily for their abundance, biocompatibility and ability to readily organize into photonic structures. Here, we review some examples complex and hierarchical photonic structures found in nature and we illustrate the fabrication process to produce scalable novel photonic structures using low cost materials in ambient conditions.


References

[1] Moyroud, E., Wenzel, T., Middleton, R., Rudall, P.J., Banks, H., Reed, A., Mellers, G., Killoran, P., Westwood, M.M., Steiner, U., Vignolini, S. Glover, J.B, (2017) Nature doi:10.1038/nature24285
[2] Onelli, O.D., Kamp, T.V.D., Skepper, J.N., Powell, J., Rolo, T.D.S., Baumbach, T., Vignolini, S. Development of structural colour in leaf beetles (2017) Scientific Reports, 7 (1), art. no. 1373.
[3] Parker, R.M., Guidetti, G., Williams, C.A., Zhao, T., Narkevicius, A., Vignolini S. and Frka-Petesic B. in press (2017) Adv Mat
[4] Frka-Petesic, B., Guidetti, G., Kamita, G., Vignolini, S. Controlling the Photonic Properties of Cholesteric Cellulose Nanocrystal Films with Magnets (2017) Advanced Materials, 29 (32), art. no. 1701469.
[5] Kamita, G., Frka-Petesic, B., Allard, A., Dargaud, M., King, K., Dumanli, A.G., Vignolini, S. Biocompatible and Sustainable Optical Strain Sensors for Large-Area Applications (2016) Advanced Optical Materials, 4 (12), pp. 1950-1954.
[6] Espinha, A., Guidetti, G., Serrano, M.C., Frka-Petesic, B., Dumanli, A.G., Hamad, W.Y., Blanco, A., López, C., Vignolini, S. Shape memory cellulose-based photonic reflectors (2016) ACS Applied Materials and Interfaces, 8 (46), pp. 31935-31940.

Cellulose derivatives (CD) offer an attractive alternative to cellulose, due to their solubility in everyday organic solvents. In this work three cellulose derivatives; ethyl cellulose, cellulose acetate and carboxymethyl cellulose were subjected to electrohydrodynamic processing (EHD). All were processed with safe, environmentally friendly solvents; ethanol, acetone and water. Ethyl cellulose was electrospun and an interesting transitional region was identified. The morphological changes from particles with tails to thick fibres were charted and it was shown that at 25wt% EC, where fibres with 3.8µm average diameter formed. The concentration and solvent composition of cellulose acetate (CA) solutions were then changed; increasing the concentration also increased fibre size. At 10wt% CA, with acetone only, fibres with heavy beading were produced. In an attempt to incorporate water in the binary solvent system to reduce the acetone content, 80:20 acetone/water solvent system was used. It was noted that for the same concentration of CA (10wt%), the beading was reduced. Finally, carboxymethyl cellulose (CMC) was electrospun with poly(ethylene oxide) (PEO). Increasing the molecular weight of CMC increased fibre size, while reducing the CMC content in the CMC/PEO blend also increased the fibre size 1.03±0.27µm to 1.10±0.29µm.

Nanofibers of natural origin are versatile building blocks and precursors for diverse hybrid and nanocomposite materials. Their structural and chemical diversity allows for combining with organic or inorganic compounds that convey functional properties such as magnetic, catalytic, optical or electrical properties.
Here, we present recent work on the extraction of cellulose nanofibers (CNF) from olive tree pruning, an important agricultural residue in the Mediterranean region. Such cellulose nanofibers are semi-flexible, 2 nm thick fibrils with extraordinary mechanical and optical properties. We show how such cellulose nanofibers can constitute super-insulating, flame-retardant foams by combination with earth-abundant resources like sepiolite nanoclay. The foams display 50 % lower thermal conductivity values as compared to commercial polymer insulation foams, while showing high flame retardancy without the need for halogenated additives. These results can pave the way for the development of sustainable and eco-friendly thermal insulation materials.
On the other hand, the optical transparency and mechanical strength of cellulose nanofibers is ideal for the design of paper-based, opto-electronic devices. We demonstrate how CNF can substitute indium tin oxide coated glass for the construction of electro-chromic films based on self-assembly with V₂O₅ nanofibers.
Nanocellulose can not only be isolated from plants but also from gluconacetobacter bacteria as re-growing, extracellular cellulose hydrogel. These hydrogels are easily impregnated with metal salts, which upon precipitation and carbothermal reduction render sponge-like carbon-metal hybrid materials. Following this strategy we prepared carbon-Ni and carbon-Fe hybrids with attractive functional properties.

The present talk aims at designing bio-inspired polymer materials by chemical natures, materials, structures, properties, processes and functions of the living as a source of innovation and engineering. The use of one or the association of many of these inspiration sources can lead to functional building blocks and then materials by directed self-assembly.
New (meth)acrylic monomers with 100% bio-based carbons and their controlled polymerizations will be described for the elaboration of thermoplastic and elastomeric block copolymers.^{1, 2}
The intimately association between natural “Breath Figure”, as a bottom-up solvent evaporation process and the self-assembly of a building blocks panel based on soft matter will be also discussed. Hierarchically structured honeycomb films, as porous surface³, from well-defined macromolecular structures will be first described for a number of applications including iridescence⁴, bioactivity & cells adhesion⁵, CO₂/pH-responsive reversible wettability^5-6, photocatalysis⁷ or for light extraction in an Organic Light Emitting Diode⁸.
Then, photonic crystals over 100 cm² elaborated by extrusion or pressure casting processes from latexes or from water-based microgels⁹ building blocks will be shown. Finally, a fully bio-sourced formulation mimicking nacre will be demonstrated as an efficient flame retardant coating for ligno-cellulosic building insulation materials for a sustainable transition.¹⁰


References
[1] S. Noppalit, J. Asua, L. Billon, to be submitted, 2017.
[2] F. Dergal, A. Khoukh, I. Chikhi, D. Lerrari, K. Bachari, L. Billon,^, to be submitted 2017.
[3] a) A. Munoz-Bonilla, M. Save, L. Billon, J. Rodriguez-Hernandez Polymer Surfaces in Motion: Unconventional Patterning Methods, Ed. Springer USA, 2015, Chapter 10, p 219-256. b) A. Bertrand, A. Bousquet, C. Dagron-Lartigau, L. Billon Chem Comm, 2016, 52, 9562. c) E. Ji, V. Pellerin, F. Ehrenfeld, A. Laffore, A. Bousquet, L. Billon Chem Comm, 2017, 53, 1876.
[4] L. Billon, M. Manguian, V. Pellerin, M. Joubert, O. Eterradossi, H. Garay Macromolecules 2009, 42, 345.
[5] H. Yin, A.L. Bulteau, Y. Feng, L. Billon Adv. Mat. Interfaces 2016, 3, 1500623.
[6] a) P. Escalé, L. Rubatat, C. Derail, M. Save, L. Billon Macro. Rapid. Comm 2011, 32, 1072. b) P. Escalé, W. Van Camp, F. DuPrez, L. Rubatat, L. Billon, M. Save, Polymer Chemistry, 2013, 4, 4710.
[7] L. Pessoni, S. Lacombe, L. Billon, R. Brown, M. Save Langmuir 2013, 29, 10264.
[8] A. Bertrand, F. Dumur, M. Perrin, M. Mruczkiewicz, C. Dagron-Lartigau, A. Bousquet, L. Vignau, L. Billon, S. Fasquel, Organic Electronic : Physics, materials, applications, asap, 2017.
[9] a) M. Boularas, E. Gombart, J.F. Tranchant, L. Billon, M. Save Macro. Rapid. Comm. 2015, 36, 79. b) M. Boularas, E. Deniau-Lejeune, V. Alard, J.F. Tranchant, L. Billon, M. Save Polym Chem. 2016, 7, 350. c) M. Boularas, L. Billon, E. Gombard, M. Save, JF Tranchant PCT/FR/050009, WO2016110615 A1, 2015.
[10] C. Baguenard, G. Labat, L. Billon, Patent FR1660640, 2017.

Cellulose nanofibrils (CNF), extracted from plant cell walls, are mechanically strong and environmentally friendly. They can be prepared into networks/gels with tunable porosities from a solution phase. The resulted networks/gels can serve as scarfolds/membranes to load or separate materials in energy devices, such as, fuel cell or in the water purification. Their structures are closely related to the mechanisms of the preparation methods and directly influence the materials' properties. Thus, it is of great importance to unravel the structure evolution upon sample preparation. In this work, osmotic dehydration, a sophisticated preservation method in food industry, has been used to prepare carboxylated cellulose-nanofibril gels with different concentrations from 0.5 wt% to 4.9 wt%. The corresponding structures of CNF gels were characterized by small angle X-ray scattering (SAXS). These CNF gels could be depicted via a hierarchical model consisting of mass fractal structures and two-stage gel structures. Upon increasing the concentration, SAXS showed that an isotropic-anisotropic transition occurred in the gels when optical birefringence started to show. Coincidentally, their fractal dimension reached a minimum value at the transition point, whereas the strain of the gel flow-point determined by the rheology became the largest. Nevertheless, both characteristic lengths of the two-stage gel structures shrinks by following a power-law decay as the concentration increases. The CNF gels prepared via osmotic dehydration have displayed rich structures, as well as interesting properties. Thus, this preparation method demonstrates a good potential of producing CNF-templated materials.

Laccase, a multicopper oxidase, can be used in water treatment processes for the removal of pollutants. This study presents activity of laccase from Rhus vernicifera adsorption on sepiolite and sepiolite modified with chitosan and Cu(II). Adsorption of laccase on raw sepiolite increased its activity by 250±40% compared to the non-adsorbed enzyme, whereas for Cu–S9–chitosan and S9–chitosan activity enhancement was by up to 700% and 500%, respectively. The stronger enhancement for the Cu-containing sorbent suggests that exchangeable Cu has some effect on the adsorbed laccase. Desorption of the adsorbed laccase was less than 10%, and the non-desorbed enzyme retained high activity. This study suggests that chitosan-sepiolite based composites might be used as efficient support for laccase immobilization, resulting in an effective active sorbent for organic pollutants sensitive to laccase oxidative activity.

Cellulose is the most abundant source of organic polymers on earth and holds promise for efficient conversion into biofuels. Its largest source is the plant cell wall which is a complex structure of cellulose microfibrils forming a heterogeneous mixture with biopolymers like hemicellulose and pectin. The structure and assembly of these constituents in the plant cell wall is still not well understood. Many structural characteristics of cellulose microfibrils like preferred orientation and crystallinity are important for its role as source of biofuels. We attempt to study these characteristics of cellulose microfibrils through Grazing incidence wide angle X-ray scattering (GIWAXS). It is a morphological characterization technique that can probe not only the surface but also beneath it by tuning the angle of incidence. The grazing incidence X-ray beam geometry yields high signal-to-noise ratio and lesser radiation damage, making it ideal for plant cell wall samples that are fragile and weakly scattering. In our work, we find that GIWAXS can decouple scattering from cellulose crystals and epicuticular wax in onion epidermal cell walls. It also reveals a preferred orientation of cellulose crystals. The GIWAXS data from different scales of onion also reveals the dependence of degree of orientation on the age of tissue.

Poly(lactic acid) (PLA) is a biobased and biodegradable polymer with relative high strength and stiffness, but low toughness. Previous studies aiming to develop modified PLA materials were fruitful towards tougher and more ductile PLA for durable applications. Yet, these strategies often involved problems such as complex synthesis and extra cost to PLA resin which are not industrially desirable. Moreover, strength and modulus were very often sacrificed as a result of the toughening approach. Here we report our study of PLA-organosilane hybrid materials towards supertough PLA. By simply mixing a low amount (0.5–1 wt %) of organoalkoxysilane with PLA, supertough PLA hybrids with over 12-fold elongation to break and 10-fold toughness were achieved. Through thermal, mechanical, electron microscopical study, and dynamic light scattering, we proved the in-situ formation of PLA-silane interpenetrating core-shell network structure, which we believe have contributed the excellent mechanical property of the new materials. This approach may also be applied to other polymer and composite systems.

Poly(ionic liquid)s (PILs) are peculiar polyelectrolytes that ideally combine the unique properties of ionic liquids (high ionic conductivity, thermal, chemical and electrochemical stabilities) with those of polymers (mechanical stability, processing and tunable macromolecular design). We have pioneered in 2013 a new class of PILs having 1,2,3-triazolium cationic groups in the repeating unit as innovative functional and dynamic ion conducting polymer materials. Their synthesis merges the robust and orthogonal nature of the copper(I)-catalyzed azide-alkyne cycloaddition, the quantitative nature of the N-alkylation of 1,2,3-triazoles and anion metathesis reactions, together with different chain growth or step growth polymerization techniques. Establishment of precise structure/properties relationships allowed the development of several ion conducting materials having high thermal, chemical and electrochemical stabilities as well as high ionic conductivity. In addition, we have shown that polymer networks having 1,2,3-triazolium cross-links possess the appealing attributes of vitrimers where dynamic exchange through trans-N-alkylation reactions afford materials that can be reprocessed, reshaped and recycled. The latest developments in poly(1,2,3-triazolium) materials and their potential applications as solid electrolytes and dynamic materials will be presented.

The attractive optoelectronic properties of conjugated polymers have led to intense research to understand their semiconducting properties and to explore their applications in various devices. [Nature.Comm.5, 3180 (2014)] It is increasingly recognized that properties of conducting polymers can be affected by nuclear quantum effects an related isotopic substitution. [J.Phys.Chem.Lett., 8, 4333 (2017)] Here, we report an experimental and theoretical study of the isotopic effects of deuterium substitution on the properties of poly(3-hexylthiophene) (P3HT). The effects of deuterium isotope substitution on P3HT chain stacking is studied experimentally by X-ray diffraction (XRD) in combination with gel permeation chromatography and theoretically by density functional theory, quantum molecular dynamics, and discrete variable representation of nuclear wave functions. For four P3HT materials with different levels of deuteration (pristine, main-chain deuterated, side-chain deuterated, and fully deuterated), the XRD measurements show that main-chain thiophene deuteration significantly reduces crystallinity, regardless of the side-chain deuteration. It is found that the P3HT crystal structure is characterized by an anti-ferroelectric packing motif of the thiophene backbone. The reduction of crystallinity due to the main-chain deuteration is a quantum nuclear effect resulting from a static zero-point vibrational energy combined with a dynamic correlation of the dipole fluctuations. Specifically, it is attributed to a smaller crystal-field stabilization, and to a lower dynamic polarizability of the C-D bond, compared to the C-H bond. The quantum molecular dynamics simulations of the protons and deuterons confirm the inter-chain correlation of the proton-proton and deuteron-deuteron motions, but not of the proton-deuteron motion. It suggests that isotopic purity is an important factor that affects the stability and properties of conjugated polymer crystals, which should be considered in the design of electronic and spintronic devices. The current findings have an important implication in both fundamental science and device engineering, and pave the way to rationally tune conjugated polymers towards desired crystallinity that would drive a particular property more effectively.

Understanding of the relationships between ionomer chain morphology, dynamics and counter ion mobility is a key factor in the design of ion conducting membranes for battery applications. In this study, we investigate the influence of electrostatic interaction strength (l_B) between randomly charged copolymers (ionomers) and counter ions on the structural and dynamic features of a model system of random ionomer melts. Using Coarse-Grained Molecular Dynamics (CGMD) simulations, we find that variations in l_B remarkably affect the formation of ionic aggregates (charged monomer – counter ion clusters), ion mobility, and polymer dynamics for a range of average charge fractions. Specifically, an increase in l_B leads to larger ionic cluster sizes and reduced polymer and ion mobility. Analysis of size distribution of the clusters along with clustering morphology characterization further reveals a percolation point at which the system undergoes a transition from discrete clusters to a percolated cluster. Finally, at sufficiently high values of l_B, we observe arrested heterogeneous ions mobility, which is correlated with an increase in ion cluster size. These findings provide insights into the role of electrostatics in governing the nanostructures formed in ionomers.

Polymeric ionic liquids or poly(ionic liquid)s (PILs) have been blossoming at the interface of many areas leading to a renaissance of the field of polymers. PILs are a subclass of polyelectrolytes that comprise IL species connected through a polymeric backbone to form a macromolecular framework¹. Some of the remarkable IL features, in particular the unique tunability of their physical and chemical properties, are maintained in the polymer, opening the door to the creation of a new platform for the development of engineered functional polymeric materials.
Among the many successful applications of PILs, those that deal with gas/vapour separation are among the most promising. In this work, we will present a perspective on different strategies to design innovative membranes and coatings for gas separation and sensing. The aim is not only to show the versatility of these polymers in the development of advanced gas separation membranes² and specific gas sorptive coatings³, revealing insights into the relationships between PIL structure and gas transport properties, but also to highlight relevant issues related to their processability, which is perhaps the most limiting step preventing the widespread application of these materials.
1. J. Yuan, D. Mecerreyes and M. Antonietti, Prog. Polym. Sci., 2013, 38, 1009-1036.
2. L.C. Tomé and I.M. Marrucho, Chem. Soc. Rev., 2016, 45, (10), 2785-2824
3. D.J.S. Patinha, L.C. Tomé, M. Isik, D. Mecerreyes, A. J. D. Silvestre, I.M. Marrucho, Materials, 2017, 10(9): 1094-2007.

Azole compounds, such as imidazole, triazole, thiazole, and oxazole, are important and versatile five-membered nitrogen heterocyclic compounds with characteristic properties. In particular, thiazole is a widely used electron-accepting heterocycle; consequently, various thiazole-based molecules have been introduced into organic semiconductors. Azolium salts, such as imidazolium- and triazolium-salts, have been attracted significant attention as a representative member of ionic liquids. Ionic liquid-based block copolymers have continued to attract widespread interest because of their characteristic ionic conductivity and the ability to self-assemble into hierarchical structures. Here we present versatile methodologies for tuning the assembled structures of azole- and azolium-based block copolymers and how this affects their performance in different applications, such as memory devices and ion conductive materials.
Recently, we have developed an efficient strategy for the synthesis of core cross-linked core-shell nanoparticles with various optoelectronic functions, involving donor-type and donor-acceptor type conjugated polymers, fluorescent and electron-deficient (acceptor-type) units. Core cross-linking is one of the most useful strategies to fix the micelle structures, which can afford the structural stability of assembled structures and introduce additional functional units into the core moiety. Novel core–shell nanoparticles with pi-conjugated and optoelectronic cores were synthesized by Suzuki coupling reaction between the cross-linkable (di)bromide groups in block copolymers and diboronic acid compounds, following the formation of micelles. A series of non-volatile organic field-effect transistor memory devices using the core cross-linked nanoparticles as charge-storage electrets have been successfully demonstrated. Water-soluble benzothiazole-based nanoparticles with characteristic thermoresponsive, fluorescent, and solvatochromic properties, were also developed as a new family of semiconductor nanomaterials with many potential applications.
We also describe the controlled synthesis of imidazolium- and triazolium-based block copolymers that exhibit characteristic ion-conducting properties, depending on the structure of the substituent group, counter anion, comonomer structure, and composition. Ion conductive core-shell nanoparticles with cross-linked cores were synthesized using self-assembled block copolymers comprising N-vinyl-1,2,4-triazolium salt and a site-selective cross-linking in selective solvent. The triazolium-based nanoparticles with the cross-linked cores and hydrophobic shell exhibited ionic conductivities more than 10^-3 S/cm at 90 ^oC and 10^-4 S/cm at 25 ^oC.

Poly(ionic liquid)s (PILs) are a class of polyelectrolytes prepared via polymerization of ionic liquids or sometimes via chemical modification of existent polymers through ion exchange, N-alkylation, and ligation of ILs onto functional neutral polymers. The current research activities are dominated by the imidazolium-based ones, because imidazolium ILs have been exhaustively studied in IL field and the knowledge in their chemistry, physics and processing has been well documented. Nevertheless, the seek for novel polymer backbones, cations, or anions is a continuous effort in the community to enrich the structure toolbox and search for new physical properties and functions. Polymers or their networks containing 1,2,4-triazolium ionic liquid species are rarely reported.[1,2] To the best of our knowledge, so far only Shreeve and Miller et al. discussed 1,2,4-triazolium-bearing polymers and crosslinked PIL networks, respectively.
In this contribution, we report the synthesis of a series of poly(4-alkyl-1-vinyl-1,2,4-triazolium) PIL either via straightforward free radical polymerization of their corresponding ionic liquid monomers or via anion metathesis of the polymer precursors bearing halide as counter anion.[3,4] In parallel to our work, Mori et al. reported the controlled synthesis of similar poly(1,2,4-triazolium)s by reversible addition-fragmentation chain transfer polymerization technique.[5] Depending on the alkyl chain length from ethyl, to hexyl and longer ones than decyl substituent, PILs from water-soluble chains, to vesicles and finally to multilamellar nanoparticles could be realized in different media, showing their structural diversity on a nanoscale. Due to the unique physical and chemical property of 1,2,4-triazolium IL species in the polymer chains, such PILs showed particular interaction mechanism with metal species via a possible carbene intermediate. As a result, a higher loading capacity of transition metal ions and a stronger stabilization effect towards transition/noble metal nanoparticles than normal polyimidazoliums have been observed.
[1] Xue, H.; Gao, H.; Shreeve, J. M,. J. Polym. Sci. Part A: Polym. Chem. 2008, 46, 2414.
[2] De La Hoz, A. T.; Miller, K. M., Polymer 2015, 72, 1.
[3] Zhang, W.; Yuan, J.:* Macromol. Rapid Commun. 2016, 37, 1124.
[4] Zhang, W.; Kochovski, Z.; Lu, Y.; Schmidt, B. V. K. J.; Antonietti, M.; Yuan, J., ACS Nano, 2016, 10, 7731.
[5] Nakabayashi, K.; Umeda, A.; Sato, Y.; Mori, H., Polymer, 2016, 96, 81.
[6] Sun, J.; Kochovski, Z.; Zhang, W.; Kirmse, H.; Lu, Y.; Antonietti, M.; Yuan, J., J. Am. Chem. Soc., 2017, 139, 8971.

Flexible electronic devices generally integrate inorganic materials on a polymer substrate (such as metal films on a deformable polymer). The properties of these inorganic/organic hybrids are of great practical and theoretical. There have been numerous experimental and theoretical study of their mechanical properties, especially the failure strain of polymer-supported metal films. The fracture strain of polymer-supported thin metal films is significantly higher than that of free-standing metal films due to the suppressed necking in the supported metal film. However, there are few studies of the thermal conductivity of extremely strained metal films and inorganic/organic hybrids. Here, we experimentally measure the thermal conductivity of extremely strained polyimide-supported Au nanofilms (100 nm Au on 25.4 µm polyimide). The systematic study of interrelated mechanical, electrical, and thermal properties leads to a better understanding of the performance of flexible electronic devices across a range of realistic operating conditions. In addition, the validity of Wiedemann-Franz law for extremely strained metal is evaluated by comparing the measured thermal and electrical conductivities.

A unique approach was adopted to drive the multiwall carbon nanotubes (MWNTs) to the interface of an immiscible PVDF/ABS blends by wrapping the nanotubes with a mutually miscible homopolymer (PMMA). A tailor made interface with an improved stress transfer was achieved in the blends with PMMA wrapped MWNTs. This manifested in an impressive 108% increment in the tensile strength and 48% increment in the Young’s modulus with 3 wt% PMMA wrapped MWNTs in striking contrast to the neat blends. As the PMMA wrapped MWNTs localized at the interface of PVDF/ABS blends, the electrical conductivity could be tuned with respect to only MWNTs which was selectively localized in the PVDF phase, driven by thermodynamics. The electromagnetic shielding properties was assessed using a vector network analyser in a broad range of frequency, X-band (8-12 GHz) and Ku –band (12-18 GHz). Interestingly, enhanced EM shielding was achieved by this unique approach. The blends with only MWNTs shielded the EM waves mostly by reflection however, the blends with PMMA wrapped MWNTs (3 wt%) shielded mostly by absorption (62%). This study opens new avenue in designing materials which show simultaneous improvement in mechanical, electrical conductivity and EM shielding properties.

Enzymes can perform many industrially relevant reactions, such as esterification, hydrolysis, oxidation, reduction, and C-C bond formation, with high specificity and under significantly milder conditions than their chemical counterparts. They can perform these reactions on a wide range of substrates, making them highly attractive for many applications. As a result, research into the use of enzymes as industrial biocatalysts has been gaining ground, particularly in conjunction with emerging solvent systems such as ionic liquids. However, enzymes often have very low solubilities in nonaqueous environments and are frequently unstable, limiting the window of usability. Consequently, there is a need to develop new biotechnologies that improve solubility and stability of biocatalysts in nonaqueous media.

Surface modification of proteins, to yield protein-polymer surfactant nanoconjugates, has been demonstrated as a robust method for synthesizing protein-rich biofluids that are devoid of any solvent. This new class of biomaterial has been shown to be a promising new technology where enzymes have been stabilized in non-aqueous environments. Using a variety of spectroscopic and scattering techniques, these novel biomaterials have been shown to allow for extreme enzyme thermal stability¹, stability against aggregation², and retained dynamics³ and function⁴. Importantly, biofluids of the industrially relevant enzyme lipase showed that enzyme activity was not only retained in the absence of water, but actually enhanced at temperatures up to and including 150 °C⁵.

Recently, we showed that protein-polymer surfactant nanoconjugates are soluble in both hydrophilic and hydrophobic ionic liquids, and we demonstrated that biomolecule architecture can be preserved in the non-aqueous environment. Furthermore, the solubilized protein displayed improved thermal stability as compared to aqueous solutions⁶. Here, we show recent results involving nanoconjugates of the enzyme glucosidase in anhydrous ionic liquids. Particularly, we demonstrate that the enzyme has significantly improved activity at 120 °C, and importantly, activity towards water insoluble cellulose. As a result, this nascent technology could provide a platform for biocatalysis in industrially relevant nonaqueous solvent systems.

(1) Brogan, A. P. S. et al. Chem. Sci. 2012, 3, 1839–1846.
(2) Brogan, A. P. S. et al. J. Phys. Chem. B. 2013, 117, 8400–8407.
(3) Gallat, F.-X.; Brogan, A. P. S. et al. J. Am. Chem. Soc. 2012, 132, 13168–13171.
(4) Perriman, A. W.; Brogan, A. P. S. et al. Nat. Chem. 2010, 2, 622–626.
(5) Brogan, A. P. S. et al. Nat. Commun. 2014, 5, 5058.
(6) Brogan, A. P. S., and Hallett, J. P. J. Am. Chem. Soc. 2016. 138, 4494-4501.

Peptide has recently been demonstrated as a sustainable and smart material for piezoelectric energy conversion. Utilizing both piezoelectric and triboelectric effects is of significant research interest due to their complementary energy conversion mechanisms. We discovered a simple and efficient approach to integrate the piezoelectric nanogenerator with triboelectric nanogenerator. The stacking one layer atop the piezoelectric peptide-based nanogenerator to form the single-electrode triboelectric nanogenerator eliminate the needed extra electrode and complicated connection found in other devices. The energy conversion process is simplified and improved. This work demonstrated the first biomaterial-based hybrid nanogenerator and significantly advanced the study of smart biomaterials. Encouraged by the performance of the peptide-based hybrid device, smart biomaterials will attract increasing research interests in the near future.

Reference:
V. Nguyen, R. Zhu, K. Jenkins, R. Yang, Self-assembly of diphenylalanine peptide with controlled polarization for power generation, Nature Communications 7, 13566 (2016).
V. Nguyen, S. Kelly, R. Yang, Piezoelectric peptide-based nanogenerator enhanced by single-electrode triboelectric nanogenerator, APL Materials 5, 074108 (2017).

There is longstanding interest in the production of polymeric materials from renewable feedstocks such as vegetable oils and their fatty acids derivatives. However, functional nanostructured polymers produced from these materials have been rarely reported. Here, we present a novel strategy of template-assisted self-assembly to fabricate ordered polymeric structures from sustainably derived species. Structure-directing molecules are employed to template the assembly of plant-derived fatty acids into highly ordered columnar (Col) or lamellar liquid crystals (LCs). We systematically study the thermotropic behaviors of the Col and lamellar phases, respectively, and the physics involved in their macroscopic alignment. The aligned Col or lamellar LCs can be robustly crosslinked to retain the original LC morphologies by photo-initiated polymerization. We demonstrate the high fidelity retention of highly ordered nanostructured morphologies in the resultant polymers by characterizations using X-ray scattering, transmission electron microscopy, and atomic microscopy. We also show that the aligned Col structures can be utilized for applications in high-performance nanofiltration membranes whereas the ordered lamellar structures provide a path to scalable fabrication of polymer nanosheets.

Development of porous materials consisting of polymer host matrix enriched with bioactive ceramic particles to initiate cellular organism reproduction while maintaining mechanical reliability in vivo is a long-standing challenge for permanent bone substitutes. Aromatic thermosetting copolyester (ATSP), introduced in the late 1990s, utilizes low cost, easily processable and highly crosslinkable oligomers to develop a high-performance polymer system. The crosslinked morphology of ATSP formed by aromatic polyester backbone interconnected via covalent oxygen bonds enables strong physical properties and outstanding chemical inertness. We recently introduced ATSP nanocomposites for which near-homogenous distribution and good incorporation of nanofillers contribute to significantly enhanced physical properties. As well, a prior biocompatibility study on ATSP morphology demonstrates direct-contact cytotoxicity test results that fibroblasts remain healthy and adhered on ATSP specimens following an incubation period. In addition, having strong adhesive bonding with metals, significant specific impact energy absorption capacity, and promising tribological properties, ATSP bionanocomposites are hence strong candidates for various orthopedic implant applications. Here, we demonstrate hydroxyapatite bioceramic particles (HAs) reinforced aromatic thermosetting copolyester matrix bionanocomposite, within the scope of providing an insight into interfacial interaction and coupling mechanisms between the HAs and ATSP matrix. The ATSP bionanocomposite is fabricated through solid-state mixing a matching set of precursor oligomers with HA particles. During endothermic condensation polymerization reaction, the constituent oligomers form a mechanochemically robust crosslinked aromatic backbone while incorporating the HAs into a self-generated cellular structure. We initially discuss the physicochemical effects induced by the HAs on the thermal polymerization reaction. Morphological analysis demonstrates near-homogenous distributions of the HAs within both precursor oligomer domain and nanocomposite matrix. Mechanical characterization shows a crack-arresting mechanism induced by the HAs which promotes a deformation-tolerant morphology with relatively enhanced material toughness. Chain relaxation dynamics in the glass transition regime are altered by segmental confinement of the polymer network instigated by the HAs. Chemical spectroscopy of the backbone chain configuration shows the formation of a covalent interfacial coupling between the HAs and ATSP matrix. A follow-up study will focus on systematical biocompatibility analysis of the ATSP matrix and ATSP bionanocomposites in various biological environments. This work may also initiate further characterization efforts on intermolecular interactions between the bioceramic particles and biocompatible polymer systems toward developing advanced synthetic bone morphologies.

Dust particles are directly linked to environmental and health issues, including lung cancer, leading to current environmental regulations that emphasize the development of effective dust control methods. Although a variety of suppressants composed of chemicals and polymers are used to reduce dust emission, those suppressants are commonly effective for short-term, are often corrosive to machinery, and can cause potential risks to human health due to the toxicity of chemicals in suppressant formulations. We developed biocompatible polymer formulations for environmentally friendly and long-term stable dust control methods. Some polymers are non-toxic enough to be applied to food, cosmetics, and pharmaceutical applications. Among those, we chose hydrophilic and amphiphilic liquid polymers to enhance the wettability of dust mass, thus reducing dust pollution, and investigated the effects of the liquid state and hydrophobicity of polymers to suppress dust. Hydrophilic and amphiphilic polymers of 5% or less in the formulation successfully reduced dust emission up to 95%. Even under experimental conditions that mimic extreme arid environments of 60^oC, the polymers maintained their liquid state for more than two months, indicating the potential for long-term stability with the developed formulations. Interestingly, the amphiphilic polymer showed better dust suppression than the hydrophilic polymer. Using a combination of techniques, including transmission electron microscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy, we studied dust control mechanisms of liquid polymers and how the hydrophobic blocks in the amphiphilic polymer enhance dust suppression.

For understanding and tuning the properties of polymers, bio- and bio-inspired polymers chemical analysis with spatial resolution on the milli- micro- and nanometer scale and even in situ is necessary. Energy dispersive X-ray spectroscopy (EDS) in the electron microscope is one method to get information on chemical composition on all those length scales and down to atomic resolution. Samples resembling a close to natural state are often highly topographic, may need in-situ analysis and can be beam sensitive. The interface between soft and hard materials, e.g. hard inclusions to enhance certain polymer properties or nanoparticles in tissue, poses another challenge for this type of analysis. The investigation of nano-sized objects and of their distribution and embedding on the nm- and even smaller scale demands for high end instrumentation on both, the microscope and detector side. Preparation artefacts and absorption effects need to be considered.
We report on the use of existing technology and on advances in instrumentation for element mapping of bulk and electron transparent samples challenging as just described. The examples range from STEM- and T-SEM (TEM in SEM) suitable samples, including single atoms in carbonaceous material [1] to highly topographic bulk samples such as porous polymers with hard inclusions [2] and crystals formed by bio-mineralization in plants, insects and bacteria.
Available low and high end detector arrangements and respective successful measurement conditions and analysis strategies will be explained. Advancement in silicon drift detector (SDD) technology provides annular and multiple detector arrangements, such as the Flat Quad (with over 1sr solid angle) [3], suitable for high take of angle experiments, and large single detector arrangements, such as an oval detector (with up to 0.7sr solid angle) for TEM [1]. Thus, efficient EDS analysis of large, topographic bulk-, electron transparent and beam sensitive samples becomes possible.
[1] Stroud R M et al. Appl. Phys. Lett. 108 163101 (2016).
[2] Da Silva Dalto DP, Master's thesis, Escola de Química, UFRJ, Rio de Janeiro, Brazil (2010).
[3] Terborg R, Rohde Microsc. Microanal. 17 (Suppl.2) 892 (2011).

Photocatalysis has received consideration attention for a variety of energy, environmental, and biomedical applications, such as hydrogen generation, and water/air purification, carbon dioxide reduction, desalination, and disinfection. Recently, visible light-driven plasmonic photocatalysis consisting of noble metal (e.g. Au and Ag) and semiconductor nanoparticles have been widely studied. To overcome the drawback of photoabsorption only in the ultraviolet region (< 420 nm) for typical semiconductor photocatalysts (e.g. TiO₂ and ZnO) with wide bandgap energy (> 3.0 eV). However, such approaches are often intrinsically limited for large-scale and eco-friendly production. In addition, potentially hazardous effects associated with semiconductor nanoparticles have limited the widespread utilization for environmental remediation. In this respect, our study is focused on identifying and characterizing plasmonic photocatalyst-like materials that exist in nature. We report that transgenic hybridization of far-red fluorescent protein (mKate2) and silk serves a new class of genetically encoded photosensitization activated by green (visible) light, generating selective reactive active species (ROS) of superoxide anion (O₂^-) and singlet oxygen (¹O₂) in a similar manner of plasmonic photocatalysis. The ROS of O₂^- and ¹O₂ generated from mKate2 silk are detected using fluorescent sensing probes. Its photocatalytic effects are demonstrated on organic dye removal and bacteria inactivation. Even more, mKate2 silk can be mass-produced by scalable and continuous manufacturing using the currently available textile infrastructure. Using the polymeric nature of silk, mKate2 silk can also be processed into nanomaterials and nanostructures in a variety of forms. mKate2 silk can overcome the limitation of potential adverse effects associated with foreign nanoparticles. Thus, we envision that this bioreactor could potentially open an alternative green manufacturing strategy for the next-generation of visible light-driven photocatalysts.

Emerging wearable and implantable biomedical energy harvesters require efficient power conversion from flexible, biocompatible, lightweight and tailorable piezoelectric materials. Many piezoelectric materials, e.g. ZnO, barium titanate (BTO, BaTiO₃), Lead zirconate titanate (PZT, Pb[ZrxTi1-x]O₃), NaNbO₃, (1-x)Pb(Mg_1/3Nb₂/3)O₃-xPbTiO₃ (PMN-PT), etc., have been explored as energy harvesters. Unfortunately, most of them are bulky, rigid, toxic, difficult to fabricate and expensive. Polyvinylidene difluoride (PVDF) and its copolymers PVDF-TrFE eliminate these disadvantages and provide a much better choice because it is biocompatible, cost-effective and intrinsically super flexible. However, PVDF-TrFE owns lower piezoelectric charge coefficients d₃₁, and d₃₃. Thus, it would be very prominent to enhance larger power output provided with same volumes. Till now, various methods have been explored and achieved to enhance piezoelectric charge coefficients of PVDF-TrFE polymer, e.g. β-phase enhancement by annealing and mixing with nanoparticles, sponge-like structures by etching ZnO nanoparticles, etc., however, their electrical performance are still not satisfactory. In addition, although some porous structures have been studied, there’re still missing literature reported on pore-size control and optimization in piezoelectric power output and also no complete understanding in corresponding size-controlled mesoporous structures for electrical output power enhancement.

Herein, we proposed a facile method to increase open-circuit voltage and short-circuit current output of PVDF-TrFE energy harvesters through optimizing mesoporous structures in PVDF-TrFE body. The mesoporous PVDF-TrFE films were easily fabricated using close “Breath Figure” method when the solvents were gradually dissolved by condensation water molecules and evaporated away with relative humidity (RH) under careful control and finally mesoporous matrix were left behind. It is found that the mesoporous diameters range from 1 µm to 4 µm at the condition of ambient RH controlled from 11.3% to 97.3%. Compared to solid PVDF-TrFE thin film devices, the open-circuit voltage increases about 22.3 times Vpp values, and output power after rectifying circuit enlarges about 15.5 times. It is worth noting that Voc attained highest value of 20.1V at RH of 51.4% while Isc arrived lowest of 857.4 µA. The output power measured at 10Hz achieves 0.53mW/cm² at RH of 51.4%. COMSOL simulation confirmed the theory on piezoelectric charge coefficient enhancement induced by mechanical stress enhancement. Time-domain and frequency-domain simulations are also achieved with simulation to verify the experimental results. All these unique properties of RH controlled mesoporous PVDF-TrFE thin films open the possibility of substituting battery for various wearable personal electronic devices and final biological energy sources for self-powered various implantable biomedical electronic devices.

Bactericidal materials are widely pursued in the hope of counteracting the increasing prevalence of drug-resistant species. Copper, zinc and silver are metals known to effectively eliminate bacterial cultures due to their oligodynamic cytotoxic effects. Porous graphite sponges (GSs) were synthesized with two or more of these metals and are referred to herein as CuZnGS, AgCuGS, AgZnGS and AgCuZnGS each containing 7-10% total metal by mass. These GS materials were characterized with FTIR, Raman, XRD, SEM, EDXA and HRTEM. The bacterial strain E. coli, was selected as a target pathogen to observe oligodynamic properties via different exposure strategies. The bacteria were exposed to the metal GS materials and grown in a McFarland standard medium over a 48 hour period of static exposure and alternatively in the same conditions but while recirculating the liquid bacterial culture through each of the multi-metal GS samples. Measured bacterial cell count was compared to a graphite control to observe bactericidal properties.

Enhancing stability and activity of various enzymes is beneficial for applications ranging from food processing to biomedical applications. Enzyme stabilization can be achieved via conjugation of enzymes with solid substrates or other molecules. Our recent study demonstrated formation of highly thermostable enzyme-copolymer self-assembled structure with improved activity (Yadavalli, Nataraja S., et al. ACS Catalysis 7.12 (2017): 8675-8684). These studies showed that conjugates of the lysozyme (LYZ) with poly glycidyl methacrylate-oligo (ethylene glycol) methyl ether methacrylate (poly(GMA-OEGMA)) remained active even after prolonged heating at temperatures exceeding 100⁰C. Herein, we carry out molecular dynamics (MD) simulations at high temperatures using GROMACS Molecular Dynamics package. The crystal structure of LYZ (3TXJ) is solvated with TIP3P water model and CHARMM36 force field is used. We represent poly(GMA-OEGMA) with triads, with GMA unit sandwiched between the two OEGMA units (keeping the same ratio between the GMA and OEGMA as in our experiments). Our simulation results show significant stabilization of the LYZ structure at high temperatures in triad-water solution with respect to that in pure water. Time evolutions of a root mean square deviation (RMSD), a number of intra-protein hydrogen bonds (H-bonds) of LYZ and Dictionary of Secondary Structure in Proteins (DSSP) plots confirm the stabilization of the enzyme in the triad-water solution. We show that the robust stabilization is observed only at a high concentration of triads (90% w/w of polymers), in the remaining scenarios considered herein with lower concentration of polymers increasing triads content slows down unfolding process at high temperatures but does not prevent it. To summarize, our simulation show that the LYZ enveloped by copolymers (triads) remains stable at high temperatures only at high concentrations of the triads in the close vicinity of the enzyme, which prohibits water access to the enzyme. These studies are in a good agreement with our experimental findings showing significant improvement of the thermal stability of LYZ and densification of the polymer shell close to its surface. OK gratefully acknowledges NSF DMR #1460836 for financial support of SC and NSF EPSCoR OIA # 1655740 for partial financial support of ST.

Multifunctional polymer composites that include biocompatible and biodegradable linkages are integral towards advancing biomedical technology. Often, functionality is achieved via surface modification of a polymer structure, commonly via reactions with functional groups present in the polymer. Gold has a known affinity for disulfide groups, as well as beneficial bio-interactions that lead it to be a highly studied nanoparticle. In loading over the percolation threshold, these nanoparticles are able to conduct electricity. Here, click chemistry was used to attach gold nanoparticles to a disulfide containing polyurethane-urea elastomer. Gold nanoparticles were created using the Turkevich method and the particle size was determined. The effect of the hard segment chain length was examined using thermal, optical and mechanical methods and polymer solubility was tested. Optical methods were used to characterize the morphology of the coated polymer. Electrical properties of the coated polymer were tested under various strain conditions.