Download or read book Polymer and Small Molecule Designs for Anion Conducting Membranes written by Sedef P. Ertem and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells are one of the oldest sustainable energy generation devices, converting chemical energy into electrical energy via reverse-electrolysis reactions. With the rapid development of polymer science, solid polymer electrolyte (SPE) membranes replaced the conventional liquid ion transport media, rendering low-temperature fuel cells more accessible for applications in portable electronics and transportation. However, SPE fuel cells are still far from commercialization due to high operation cost, and insufficient lifetime and performance limitations. Anion exchange membrane fuel cells (AEMFCs) are inexpensive alternatives to current proton exchange membrane fuel cell (PEMFC) technology, which relies on utilizing expensive noble-metal catalysts and perfluorinated SPE materials. Unlike PEMFCs, there is not an ideal AEM material that provides efficient ion transport, while being mechanically robust and chemically stable under strong alkaline conditions. The objectives of this dissertation are to investigate macromolecular design parameters to obtain robust membranes with efficient ion conductivities, and molecular design parameters to obtain alkaline stable ammonium cations as an alternative to the benchmark benzyltrimethylammonium (BTMA) cation. Macromolecular design parameters were explored by systematic variations of polymer architecture from random, to graft, to symmetric pentablock copolymer structures. Solvent processable random copolymers of polyisoprene-ran-poly(vinyl- benzyltrimethylammonium chloride) were synthesized via polymerization of commercially available monomers. Robust membranes were obtained by thermal or photocross-linking of unsaturated isoprene units. Depending on the copolymer composition, choice of cross-linking method, and the hydrophobicity of the cross-linker, microphase-separated morphologies were obtained forming a connected network of ion clusters. Connectivity improved ion conductivity by two to three orders of magnitude even at low hydration numbers. Connected ionic networks with larger domain sizes were obtained when polymer chains with fixed cations were grafted onto a hydrophobic backbone. Systematic change of graft length and graft density showed a strong correlation with domain connectivity. At a fixed graft density, increasing graft length improved domain connectivity and ion conductivity at the expense of excessive water uptake and dimensional instability. At a fixed graft length, increased graft density improved domain connectivity due to decreased domain size and distance, without compromising membrane dimensional stability. Compared to analogous random copolymers two to three times higher ion conductivities were obtained at relatively low hydration, reaching chloride ion conductivities as high as 50 mS/cm at 60 oC and 95 % relative humidity. A symmetric ABCBA pentablock was functionalized to obtain a midblock quaternary ammonium functionalized polymer that are analogous to midblock sulfonated Nexar® pentablock copolymers which have been commercialized by Kraton Polymers. X-ray scattering and transmission electron microscopy revealed formation of a microphase-separated inverse morphology where the minor ionic component formed the connected phase. Membranes had elastomeric properties and superior water management to graft copolymers while providing two to three times higher ion conductivity at an equivalent ion concentration. This work represents the first example of a midblock quaternized pentablock copolymer and the investigation of the structure-morphology-property relationships. Lastly, improved alkaline stability of hexyltrimethylammonium (HTMA) cations were investigated on a molecular level, by systematic structural design. Phenyl, phenyl ether, and benzyl ether attached HTMA small molecule cations were synthesized. These three spacer-modified cations were found to be six to ten times more stable than the conventional BTMA cation. The linker chemistry did not influence the overall alkaline stability, enabling easy access to stable ammonium cations. Analogous styrenic monomers, and their homopolymers were synthesized. High stability of the homopolymer cations was confirmed in comparison to poly(BTMA). This study provided a deeper understanding of ammonium degradation mechanisms under strong alkaline conditions, and proposed monomer designs for easy incorporation of stable ammonium cations onto polymers.

Download or read book Synthesis and Structure property Relationships of Polymeric Membranes for Small Molecule Transport written by Haomiao Yuan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One key challenge for alkaline anion exchange membrane fuel cells is the lack of alkaline stable polycations. The synthesis of random, crosslinked and block copolymers based on the cobaltocenium phenylene norbornene (NPC) monomer is described. The polymers were synthesized from ring-opening metathesis polymerization (ROMP) of the NPC monomer showed excellent thermo-alkaline and thermo-oxidative stability. Random copolymers, crosslinked networks and amphiphilic diblock copolymers were prepared by copolymerizing NPC with different hydrophobic monomers: norbornene for random copolymers, dicyclopentadiene for crosslinked networks and a norbornene dibenzyl ether monomer for amphiphilic diblock copolymers. Mechanical robust membranes were prepared from all these copolymers. Polymers with different architectures exhibited different morphologies. Random copolymers showed disordered interconnected cobaltocenium domains with ion clusters present; crosslinked networks showed homogenous distribution of ions; the amphiphilic diblock copolymers showed cylindrical microphase separation with the cationic domains being the continuous phase even though they constituted the minor volume component. The morphologies of the membranes were found to have little effect on the water uptake of the membranes, but significantly influenced the ionic conductivity. The crosslinked membranes showed lower conductivity compared to the random copolymer membranes at the same composition. However, higher IECs can be achieved by crosslinking with concomitant improved mechanical integrity relative to their random copolymer analogs, ultimately allows for reaching higher ion conductivity values. For the diblock copolymer, formation of a conducting ion channel and elimination of the presence of ion clusters allowed for significantly higher ionic conductivity than the random copolymer or the crosslinked networks at the same composition. Poly(vinyl acetate)-b-polybutadiene-b-poly(vinyl acetate) triblock copolymer was synthesized for water/alcohol pervaporation separation membrane. A difunctional chain transfer agent (dCTA) with both reversible addition - fragmentation chain-transfer (RAFT) and ROMP functionality was synthesized. The triblock copolymers were obtained by synthesizing narrow-dispersed poly(vinyl acetate) by RAFT and subsequently inserting a polybutadiene block by ROMP. The polymers were cast as thin membranes, and the polybutadiene was crosslinked by UV radiation for mechanical robustness. Solid state hydrolysis afforded poly(vinyl alcohol)-b-polybutadiene-b-poly(vinyl alcohol) membranes. Different compositions of the polymers resulted in different morphologies. A longer polybutadiene block or a shorter poly(vinyl alcohol) block contributed to stronger phase separation. This study invented a new methodology to construct amphiphilic triblock copolymers with well-defined morphologies.

Download or read book Synthetic Design and Development of Sterically protected Hydroxide conducting Polymers for Energy Conversion Devices written by Andrew Gordon Wright and published by . This book was released on 2016 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of renewable energy conversion devices is crucial in reducing greenhouse gas emissions and sustaining the energy required for future generations. However, most energy conversion devices currently available have high costs, which greatly slow down any transition from non-renewable combustion devices. The most promising low-cost, renewable energy conversion devices are based on anion-conducting membranes, such as those found in hydrogen fuel cells, water electrolyzers, redox flow batteries, and electrodialysis. Unfortunately, the current lifetime of such devices is too short for wide-spread adoption. The main issue is the instability of the alkaline anion exchange membrane towards caustic hydroxide. While a significant amount of research has been on demonstrating materials that have longer lifetimes, little work has been concentrated on investigating the degradation pathways on small molecule model compounds. By understanding the chemistry behind their weakness, materials can be specifically designed to counter such pathways. This then leads towards specifically designed polymers with high endurance. The development towards permanently-stable, alkaline anion exchange membranes is the focus of this thesis. Throughout this thesis, new model compounds are developed and extensively characterized. Using new stability tests, the degradation pathways are identified and the stability is quantitatively compared. Novel polymers are then prepared, which are designed to mimic the highest stability small molecule compounds. Steric hindrance is found to be the most promising method towards durable cationic polymers. From Chapter 2 to Chapter 5, the prepared materials become more and more resistant to hydroxide, demonstrating development in the correct direction.

Download or read book Alkaline Anion Exchange Membranes for Fuel Cells written by Jince Thomas and published by John Wiley & Sons. This book was released on 2024-02-05 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alkaline Anion Exchange Membranes for Fuel Cells Build the fuel cells of the future with this cutting-edge material Alkaline anion exchange membranes (AAEMs) are cutting-edge polyelectrolyte materials with growing renewable energy applications including fuel cells, batteries, hydrogen electrolyzers and electrodialysis technologies. Their use in relatively new alkaline exchange membrane fuel cells (AEMFCs) is designed to produce cost-effective clean energy (electricity) produced by a chemical reaction. Rigorous studies are being conducted to meet the requirements of AAEMs precisely tailored for high anion conductivity and durability for future high energy efficient devices. Hence, over the past few years the academic and industrial scientific communities have explored various polymeric, composite and inorganic materials and studied their properties as a potential AAEM. The accumulated literature in this area of investigation is vast and in order to provide the community with the tools needed to strive forward, there is a clear need to condense this information in a single volume. Alkaline Anion Exchange Membranes for Fuel Cells meets this need with a comprehensive overview of the properties of these membranes and their applications. The book considers recent developments, common challenges, and the long-term prospects for this field of research and engineering. It constitutes a one-stop resource for the development and production of AAEM fuel cells and related electrochemical applications. Alkaline Anion Exchange Membranes for Fuel Cells readers will find: Discussion of electrochemical applications like redox flow batteries, water electrolysis, and many more Detailed treatment of specially tailored cationic groups such as quaternary ammonium and guanidinium Expert advice on efficient fabrication and electrode assembly Alkaline Anion Exchange Membranes for Fuel Cells is ideal for electrochemists, materials scientists, polymer chemists, electrical engineers, and anyone working in power technology or related fields.

Download or read book Functional Membranes for High Efficiency Molecule and Ion Transport written by Jingtao Wang and published by Springer Nature. This book was released on 2023-01-23 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of functional membranes for efficient ion/molecule transfer and separation. It first presents the design, fabrication, structure, and performance of several kinds of membranes. Then, the application of membrane technology in organic solvent nanofiltration, hydrogen fuel cells, and solid-state lithium batteries is introduced. Furthermore, the book proposes strategies of strengthening the ion/molecular-level separation and transfer process in membrane processes. It also analyzes the development status, existing problems, and optimization methods in the field of membranes and membrane processes. Finally, it highlights the construction strategy of membrane structures, the structure–performance relationships as well as the transfer and separation mechanisms. The target group of this book is academics and researchers in materials science, chemical engineering, biomedical engineering, and other related fields.

Download or read book Anion Receptor Chemistry written by Jonathan L Sessler and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anion recognition plays a critical role in a range of biological processes, and a variety of receptors and carriers can be found throughout the natural world. Chemists working in the area of supramolecular chemistry have created a range of anion receptors, drawing inspiration from nature as well as their own inventive processes. This book traces the origins of anion recognition chemistry as a unique sub-field in supramolecular chemistry while illustrating the basic approaches currently being used to effect receptor design. The combination of biological overview and summary of current synthetic approaches provides a coverage that is both comprehensive and comprehensible. First, the authors detail the key design motifs that have been used to generate synthetic receptors and which are likely to provide the basis for further developments. They also highlight briefly some of the features that are present in naturally occurring anion recognition and transport systems and summarise the applications of anion recognition chemistry. Providing as it does a detailed review for practitioners in the field and a concise introduction to the topic for newcomers, Anion Receptor Chemistry reflects the current state of the art. Fully referenced and illustrated in colour, it is a welcome addition to the literature.

Download or read book Sustainable Nanoscale Engineering written by Gyorgy Szekely and published by Elsevier. This book was released on 2019-09-18 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustainable Nanoscale Engineering: From Materials Design to Chemical Processing presents the latest on the design of nanoscale materials and their applications in sustainable chemical production processes. The newest achievements of materials science, in particular nanomaterials, opened new opportunities for chemical engineers to design more efficient, safe, compact and environmentally benign processes. These materials include metal-organic frameworks, graphene, membranes, imprinted polymers, polymers of intrinsic microporosity, nanoparticles, and nanofilms, to name a few. Topics discussed include gas separation, CO2 sequestration, continuous processes, waste valorization, catalytic processes, bioengineering, pharmaceutical manufacturing, supercritical CO2 technology, sustainable energy, molecular imprinting, graphene, nature inspired chemical engineering, desalination, and more. Describes new, efficient and environmentally accepted processes for nanomaterials design Includes a large array of materials, such as metal-organic frameworks, graphene, imprinted polymers, and more Explores the contribution of these materials in the development of sustainable chemical processes

Download or read book Nanocarbons for Energy Conversion Supramolecular Approaches written by Naotoshi Nakashima and published by Springer. This book was released on 2018-08-13 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on nanocarbons (carbon nanotubes, graphene, nanoporous carbon, and carbon black) and related materials for energy conversion, including fuel cells (predominately proton exchange membrane fuel cells [PEMFC]), Li-ion batteries, and supercapacitors. Written by a group of internationally recognized researchers, it offers an in-depth review of the structure, properties, and functions of nanocarbons, and summarizes recent advances in the design, fabrication and characterization of nanocarbon-based catalysts for energy applications. As such, it is an invaluable resource for graduate students, academics and industrial scientists interested in the areas of nanocarbons, energy materials for fuel cells, batteries and supercapacitors as well as materials design, and supramolecular science.

Download or read book Functional Supramolecular Nanoassemblies of Conjugated Molecules written by Penglei Chen and published by Frontiers Media SA. This book was released on 2020-01-13 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Π-conjugated systems of delocalized aromatic electrons along their backbones, including conjugated small molecules, oligomers, polymers, and carbonaceous materials, etc., have received considerable attention from a wide variety of scientific and technical communities. Compared to inorganic materials, the advantages of those based on π-tectons lie in their broad diversity, flexibility, and tunability with regard to structure/geometry/morphology, processability, composition, functionality, electronic/band structure, etc. In terms of sophisticated molecular engineering, these features endow them not only with excellent self-assembly properties but also with unique optical, electrical, mechanical, photophysical, photochemical, and biochemical attributes. This renders them promising scaffolds for advanced functional materials (AFMs) in numerous areas of general interest such as electronics, optics, optoelectronics, photovoltaics, magnetic and piezoelectric devices, sensors, catalysts, biomedicines, and others. With regard to the design/synthesis of novel π-tectons, the launch of diverse assembly/fabrication protocols, theoretical calculations, etc., the past several decades have witnessed tremendous advancements along this direction. Thus far, a vast array of high-performance π-tectons-based AFMs have been initiated. To some extent, the cooperative principle of π-πstacking and other noncovalent interactions has been revealed, and the structure-property relationships have been disclosed. Despite the existing progress, this field still faces challenges, for example: (i) the need for scalable assembly/manufacture under ambient conditions—with low-cost, facile, environmentally-friendly protocols (ii) clearer correlations bridging the underlying intricate relationships of each successive step in assembly/manufacture (iii) corresponding theoretical calculations for guiding the rational design of π-tectons that elucidate the cooperative principle of π-π stacking and other noncovalent interactions, as well as the principle of structure-performance correlation (iv) stability and durability, among the most important concerns regarding their commercialization The advancements accumulated during the past decades have established a solid foundation for the further development of π-conjugated systems-based AFMs. We believe that with unrelenting efforts from both scientific and technical communities of various backgrounds, their practical applications will eventually be fulfilled. This Research Topic aims to address the above-mentioned challenges

Download or read book Anion conducting Polymer Composition and Membrane written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

Download or read book Handbook of Fuel Cells written by Wolf Vielstich and published by John Wiley & Sons. This book was released on 2009-04-20 with total page 1090 pages. Available in PDF, EPUB and Kindle. Book excerpt: A timely addition to the highly acclaimed four-volume handbook set; volumes 5 and 6 highlight recent developments, particularly in the fields of new materials, molecular modeling and durability. Since the publication of the first four volumes of the Handbook of Fuel Cells in 2003, the focus of fuel cell research and development has shifted from optimizing fuel cell performance with well-known materials to developing new materials concepts, and to understanding the origins of materials and fuel cell degradation. This new two-volume set provides an authoritative and timely guide to these recent developments in fuel cell research.

Download or read book Polymer Electrolyte Fuel Cells 10 written by Hubert Andreas Gasteiger and published by The Electrochemical Society. This book was released on 2010-10 with total page 2081 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of ECS Transactions reports on research, development, and engineering of polymer electrolyte fuel cells (PEFCs), as well as low-temperature direct-fuel cells using either anion or cation exchange membranes. It discusses diagnostic techniques and systems design for both acid and alkaline fuel cells, catalysts and membranes for acid fuel cells, and catalysts and membranes for alkaline fuel cells.

Download or read book Ion Exchange Membranes written by Tongwen Xu and published by John Wiley & Sons. This book was released on 2024-05-28 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion Exchange Membranes A comprehensive introduction to the electro-membrane technologies of the future An ion exchange membrane is a polymer-based membrane which can be permeable by some ions in a solution while blocking others, making them ideal for processes such as water desalination, salt concentration control, clean production and—given their electrical conductivity—power generation and energy storage etc. Recent advances have given rise to new electro-membrane processes that promise drastically to expand the applications of this technology. Scientists in both research and industry will increasingly need to draw on these membranes in vital ways with strongly positive potential environmental impact. Ion Exchange Membranes summarizes recent research into these membranes and electro-membrane processes before moving to an overview of the historical background. It then attends in detail to cutting-edge fabrication technologies and the most recent areas of use. The result is a comprehensive introduction to the design, fabrication, and applications of these increasingly essential membranes. Ion Exchange Membranes readers will also find: In-depth treatment of industrial-scale applications Detailed discussion of topics including side-chain engineering, polyacylation, superacid-catalyst polymerization, and more Analysis of electro-membrane processes such as alkaline membrane water electrolysis, solar-driven water splitting, and many more Ion Exchange Membranes is ideal for membrane scientists, materials scientists, inorganic chemists, polymer chemists, and researchers and engineers in a variety of fields working with ion exchange membranes and electro-membrane processes.

Download or read book Smart Inorganic Polymers written by Evamarie Hey-Hawkins and published by John Wiley & Sons. This book was released on 2019-08-05 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides complete and undiluted knowledge on making inorganic polymers functional. This comprehensive book reflects the state of the art in the field of inorganic polymers, based on research conducted by a number of internationally leading research groups working in this area. It covers the synthesis aspects of synthetic inorganic polymers and looks at multiple inorganic monomers as building blocks, which exhibit unprecedented electronic, redox, photo-emissive, magnetic, self-healing and catalytic properties. It also looks at the applications of inorganic polymers in areas such as optoelectronics, energy storage, industrial chemistry, and biology. Beginning with an overview of the use of smart inorganic polymers in daily life, Smart Inorganic Polymers: Synthesis, Properties and Emerging Applications in Materials and Life Sciences goes on to study the synthesis, properties, and applications of polymers incorporating different heteroelements such as boron, phosphorus, silicon, germanium, and tin. The book also examines inorganic polymers in flame-retardants, as functional materials, and in biology. An excellent addition to the polymer scientists' and synthetic chemists' toolbox Summarizes the state of the art on how to make and use functional inorganic polymers, from synthesis to applications Edited by the coordinator of a highly funded European community research program (COST action) that focuses specifically on the exploration of inorganic polymers Features contributions from top experts in the field Aimed at academics and industrial researchers in this field, Smart Inorganic Polymers: Synthesis, Properties and Emerging Applications in Materials and Life Sciences will also benefit scientists who want to get a better overview on the state-of-the-art of this rapidly advancing area.

Download or read book Polymerized Ionic Liquids written by Ali Eftekhari and published by Royal Society of Chemistry. This book was released on 2017-09-18 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series covers the fundamentals and applications of different smart material systems from renowned international experts.

Download or read book Ion and Molecule Transport in Membrane Systems written by Victor Nikonenko and published by MDPI. This book was released on 2021-08-10 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membranes play an enormous role in our life. Biological cell membranes control the fluxes of substances in and out of cells. Artificial membranes are widely used in numerous applications including “green” separation processes in chemistry, agroindustry, biology, medicine; they are used as well in energy generation from renewable sources. They largely mimic the structure and functions of biological membranes. The similarity in the structure leads to the similarity in the properties and the approaches to study the laws governing the behavior of both biological and artificial membranes. In this book, some physico-chemical and chemico-physical aspects of the structure and behavior of biological and artificial membranes are investigated.

Download or read book Integrated Solar Fuel Generators written by Ian D Sharp and published by Royal Society of Chemistry. This book was released on 2018-09-10 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the rapid worldwide increase of interest and excitement about the promise of artificial photosynthesis for renewable fuels, the research community is beginning to focus on the challenges of integrating the various components into complete, unassisted solar fuel generators. Integrated Solar Fuel Generators discusses the scientific and engineering efforts addressing the challenges of building complete integrated artificial photosystems that will form the basis for developing a solar fuels technology. Building on recent substantial progress towards efficient semiconductor light absorbers and robust, earth abundant heterogeneous catalysts for water oxidation and proton reduction by the community, the integration of these components into efficient durable generators suitable for scale-up moves into focus. To succeed, a broad range of materials, processing, and design issues need to be addressed to meet efficiency, stability and scalability requirements. This book describes the critical areas of research and development towards viable integrated solar fuels systems, the current state of the art of these efforts and outlines future research needs that will accelerate progress towards a deployable technology.