Macrocycle-based covalent-organic-polymer as efficient oxygen electrocatalysts for zinc-air flow batteries

Macrocycle-based covalent-organic-polymer as efficient oxygen electrocatalysts for zinc-air flow batteries
Author: Yiming Leng
Publisher: OAE Publishing Inc.
Total Pages: 12
Release: 2024-04-03
Genre: Science
ISBN:

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Covalent organic polymers (COPs), as emerging porous materials with well-defined architectures and high hydrothermal stability, have attracted extensive attention in the field of electrocatalysis. Herein, we report a rational design method for preparing oxygen reduction reaction electrocatalysts with the assistance of a predesigned macrocyclic COP model molecular. With the predesigned nitrogen position and structural features in macrocyclic chain-like COP-based materials, the obtained COPMCT-Co-900 catalyst provided excellent oxygen reduction performance, where the half-wave potential (E1/2) reaches 0.85 V (vs. RHE), comparable to commercial Pt/C. We also extended the strategy to similar macrocycle COPs and Fe-based and Ni-based metal sources and studied the oxygen reduction reaction performance of corresponding catalysts, proving the universality of the method. Interestingly, we assemble COPMCT-Co-900 catalyst as air electrode catalyst of the self-made rechargeable zinc-air flow batteries, which exhibit outstanding power density (155.6 mW·cm-2) and long cycle life (90 h, 270 cycles at 10 mA·cm-2). Our studies provide a new method for the development of high-performance oxygen electrodes applied in zinc-air flow battery devices.

Macrocycles in Drug Discovery

Macrocycles in Drug Discovery
Author: Jeremy I Levin
Publisher: Royal Society of Chemistry
Total Pages: 526
Release: 2015
Genre: Medical
ISBN: 1849737010

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This series provides a comprehensive resource for postgraduate students and for scientists in academia or industry wanting to learn topics outside their own areas of expertise.

Polymer Or Macrocycle?

Polymer Or Macrocycle?
Author: Emily Kate Harris
Publisher:
Total Pages: 250
Release: 2010
Genre:
ISBN: 9783869554112

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Polymer Science: A Comprehensive Reference

Polymer Science: A Comprehensive Reference
Author:
Publisher: Newnes
Total Pages: 7752
Release: 2012-12-05
Genre: Technology & Engineering
ISBN: 0080878628

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The progress in polymer science is revealed in the chapters of Polymer Science: A Comprehensive Reference, Ten Volume Set. In Volume 1, this is reflected in the improved understanding of the properties of polymers in solution, in bulk and in confined situations such as in thin films. Volume 2 addresses new characterization techniques, such as high resolution optical microscopy, scanning probe microscopy and other procedures for surface and interface characterization. Volume 3 presents the great progress achieved in precise synthetic polymerization techniques for vinyl monomers to control macromolecular architecture: the development of metallocene and post-metallocene catalysis for olefin polymerization, new ionic polymerization procedures, and atom transfer radical polymerization, nitroxide mediated polymerization, and reversible addition-fragmentation chain transfer systems as the most often used controlled/living radical polymerization methods. Volume 4 is devoted to kinetics, mechanisms and applications of ring opening polymerization of heterocyclic monomers and cycloolefins (ROMP), as well as to various less common polymerization techniques. Polycondensation and non-chain polymerizations, including dendrimer synthesis and various "click" procedures, are covered in Volume 5. Volume 6 focuses on several aspects of controlled macromolecular architectures and soft nano-objects including hybrids and bioconjugates. Many of the achievements would have not been possible without new characterization techniques like AFM that allowed direct imaging of single molecules and nano-objects with a precision available only recently. An entirely new aspect in polymer science is based on the combination of bottom-up methods such as polymer synthesis and molecularly programmed self-assembly with top-down structuring such as lithography and surface templating, as presented in Volume 7. It encompasses polymer and nanoparticle assembly in bulk and under confined conditions or influenced by an external field, including thin films, inorganic-organic hybrids, or nanofibers. Volume 8 expands these concepts focusing on applications in advanced technologies, e.g. in electronic industry and centers on combination with top down approach and functional properties like conductivity. Another type of functionality that is of rapidly increasing importance in polymer science is introduced in volume 9. It deals with various aspects of polymers in biology and medicine, including the response of living cells and tissue to the contact with biofunctional particles and surfaces. The last volume is devoted to the scope and potential provided by environmentally benign and green polymers, as well as energy-related polymers. They discuss new technologies needed for a sustainable economy in our world of limited resources. Provides broad and in-depth coverage of all aspects of polymer science from synthesis/polymerization, properties, and characterization methods and techniques to nanostructures, sustainability and energy, and biomedical uses of polymers Provides a definitive source for those entering or researching in this area by integrating the multidisciplinary aspects of the science into one unique, up-to-date reference work Electronic version has complete cross-referencing and multi-media components Volume editors are world experts in their field (including a Nobel Prize winner)

The Plasma Chemistry of Polymer Surfaces

The Plasma Chemistry of Polymer Surfaces
Author: Jörg Friedrich
Publisher: John Wiley & Sons
Total Pages: 479
Release: 2012-05-29
Genre: Technology & Engineering
ISBN: 3527318534

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More than 99% of all visible matter in the universe occurs as highly ionized gas plasma with high energy content. Electrical low- and atmospheric-pressure plasmas are characterized by continuous source of moderate quantities of energy or enthalpy transferred predominantly as kinetic energy of electrons. Therefore, such energetically unbalanced plasmas have low gas temperature but produce sufficient energy for inelastic collisions with atoms and molecules in the gas phase, thus producing reactive species and photons, which are able to initiate all types of polymerizations or activate any surface of low reactive polymers. However, the broadly distributed energies in the plasma exceed partially the binding energies in polymers, thus initiating very often unselective reactions and polymer degradation. The intention of this book is to present new plasma processes and new plasma reactions of high selectivity and high yield. This book aims to bridge classical and plasma chemistry, particularly focusing on polymer chemistry in the bulk and on the surface under plasma exposure. The stability of surface functionalization and the qualitative and quantitative measurement of functional groups at polymer surface are featured prominently, and chemical pathways for suppressing the undesirable side effects of plasma exposure are proposed and illustrated with numerous examples. Special attention is paid to the smooth transition from inanimate polymer surfaces to modified bioactive polymer surfaces. A wide range of techniques, plasma types and applications are demonstrated.

Hybrid Macrocycles for Supramolecular Assemblies

Hybrid Macrocycles for Supramolecular Assemblies
Author: Walter Philip Watson
Publisher:
Total Pages:
Release: 2005
Genre: Macrocyclic compounds
ISBN:

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Hybrid macrocycles, which chimerically integrate multiple chemical compositions and architectures, provide an effective way to impart new properties to polymers that are not found in their linear or homocyclic analogues. This dissertation addresses the incorporation of hydrophilic blocks into hydrophobic polymer, as either a poly(dimethyl siloxane)-block-poly(oxyethylene) (PDMS-POE) tadpole with a hydrophobic head and a hydrophilic tail or as a diblock poly(styrene)-block-diethylene glycol (PS-DEG) hydrophobic-hydrophilic macrocycle. The supramolecular association properties of both kinds of cycles were studied: the PDMS-POE tadpoles in forming micelles, and the PS-DEG macrocycles in threading with linear polymer to form polyrotaxanes. For the PDMS-POE macrocycle, linear alpha, omega-dihydroxy PDMS was cyclized under dilute conditions with dichloromethylhydrosilane as a linking group to produce hydrosilane-functionalized cyclic PDMS. This was joined to alpha-methoxy, omega-allyl POE via a free radical hydrosilylation reaction to produce the hybrid tadpole macrocycle, which was analyzed by GPC, DSC, and 1H, 13C, and 29Si NMR spectroscopy. Supramolecular aggregation consisting of the formation of micelles under both polar and nonpolar conditions was studied by surface tensiometry and quasielastic light scattering. For the PS-DEG macrocycle, linear alpha, omega-dihydroxy PS was prepared by ATRP polymerization of styrene, followed by reaction with KOH to give hydroxyl endgroups. The linear PS was then cyclized under dilute conditions with diethylene glycol ditosylate, and the product was analyzed by GPC, MALDI-TOF MS, DSC, and 1H, 13C and DOSY NMR spectroscopy. The macrocycle was then statistically threaded with linear PS to give the supramolecular structure poly(styrene)-rotaxa-cyclo[poly(styrene)-block-diethylene glycol]. Characterization was performed with DOSY NMR to verify that the product was threaded, and 1H NMR was collected to determine that the product was 13% macrocycle by weight. DSC showed only one Tg, indicating that the linear and cyclic species were present in the same phase.

Macrocycles

Macrocycles
Author: Frank Davis
Publisher: John Wiley & Sons
Total Pages: 1069
Release: 2011-02-23
Genre: Technology & Engineering
ISBN: 1119990297

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Macrocyclic molecules contain rings made up of seven or more atoms. They are interesting because they provide building blocks for synthesizing precise two or three dimensional structures – an important goal in nanotechnology. For example, they can be used to develop nanosized reaction vessels, cages, switches and shuttles, and have potential as components in molecular computers. They also have applications as catalysts and sensors. Macrocycles: Construction, Chemistry and Nanotechnology Applications is an essential introduction this important class of molecules and describes how to synthesise them, their chemistry, how they can be used as nanotechnology building blocks, and their applications. A wide range of structures synthesised over the past few decades are covered, from the simpler cyclophanes and multi-ring aromatic structures to vases, bowls, cages and more complex multi-ring systems and 3D architectures such as “pumpkins”, interlocking chains and knots. Topics covered include: principles of macrocycle synthesis simple ring compounds multi-ring aromatic structures porphyrins and phthalocanines cyclophanes crown ethers, cryptands and spherands calixarenes, resorcinarenes, cavitands, carcerands, and heterocalixarenes cyclodextrins cucurbiturils cyclotriveratylenes rotaxanes catenanes complex 3D architectures, including trefoils and knots Macrocycles: Construction, Chemistry and Nanotechnology Applications distills the essence of this important topic for undergraduate and postgraduate students, and for researchers in other fields interested in getting a general insight into this increasingly important class of molecules.

Cyclic Polymers

Cyclic Polymers
Author: J. A. Semlyen
Publisher: Springer Science & Business Media
Total Pages: 804
Release: 2000-08-31
Genre: Science
ISBN: 0412830906

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Cyclic Polymers (Second Edition) reviews the many recent advances in this rapidly expanding subject since the publication of the first edition in 1986. The preparation, characterisation, properties and applications of a wide range of organic and inorganic cyclic oligomers and polymers are described in detail, together with many examples of catenanes and rotaxanes. The importance of large cyclics in biological chemistry and molecular biology is emphasised by a wide coverage of circular DNA, cyclic peptides and cyclic oligosaccharides and polysaccharides. Experimental techniques and theoretical aspects of cyclic polymers are included, as well as examples of their uses such as ring opening polymerisation reactions to give commercially important materials. This book covers a wide range of topics which should be of interest to many scientific research workers (for example, in polymer science, chemistry and molecular biology), as well as providing a reference text for undergraduate and graduate students.

Synthesis of Polymers

Synthesis of Polymers
Author: Dieter A. Schlüter
Publisher: John Wiley & Sons
Total Pages: 1229
Release: 2012-05-14
Genre: Science
ISBN: 3527327576

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Polymers are huge macromolecules composed of repeating structural units. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials. Due to the extraordinary range of properties accessible, polymers have come to play an essential and ubiquitous role in everyday life - from plastics and elastomers on the one hand to natural biopolymers such as DNA and proteins on the other hand. The study of polymer science begins with understanding the methods in which these materials are synthesized. Polymer synthesis is a complex procedure and can take place in a variety of ways. This book brings together the "Who is who" of polymer science to give the readers an overview of the large field of polymer synthesis. It is a one-stop reference and a must-have for all Chemists, Polymer Chemists, Chemists in Industry, and Materials Scientists.