Download or read book Designing Ion containing Polymers with Controlled Structure and Dynamics written by Joshua Enokida and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion-containing polymers are a unique class of materials for which strong electrostatic interactions dictate physical properties. By altering molecular parameters, such as the backbone chemical structure, the ion content, and the ion-pair identity, the structure and dynamics of these polymers can be altered. Further investigation of the molecular parameters that govern their structure-property relationships is critical for the future development of these polymeric materials. Particularly, the incorporation of ammonium-based counterions into these polymers offers a facile method to tune their electrostatic interactions and hydrophobicity. Applying this concept, a bulky dimethyloctylammonium (DMOA) counterion was used to modify the organic solubility of styrenesulfonate in order to facilitate its direct solution copolymerization with isoprene. With these poly(isoprene-ran-styrenesulfonate) (P(I-ran-SS)) copolymers the effect of ion content and the counterion identity on the structure and dynamics were evaluated. In the first project, poly(isoprene-ran-dimethyloctylammonium styrenesulfonate) (P(I-ran-DMOASS)) copolymers with high molecular weights and dimethyloctylammonium styrenesulfonate (DMOASS) compositions ranging between 8 and 40 mol% (30 - 77 wt%) were synthesized via nitroxide-mediated polymerization. Thermal and viscoelastic characterization revealed distinct behaviors for the low (30 - 51 wt%) and high (56 - 77 wt%) DMOASS content copolymers. Three structural regimes were identified: ion clusters (30 wt% DMOASS), continuous ionic phase (56 - 77 wt% DMOASS), and the coexistence of the two (42 - 51 wt% DMOASS). As DMOASS content increased, small angle X-ray scattering revealed a gradual transition from the characteristic ion cluster structure to a smaller, more regular backbone-backbone structure associated with a continuous ionic phase. The ion clusters acted as physical crosslinks and introduced additional elasticity into the low DMOASS content copolymer, while the continuous ionic phase showed restricted flow behavior and the disappearance of a definitive plateau modulus. Dynamic mechanical analysis revealed two distinct Tg's at intermediate DMOASS content, indicating the coexistence of both structures. In the second project, the role of counterion sterics on the structure and dynamics of a low glass transition temperature, amorphous P(I-ran-SS) at low ion contents (7 mol%) was investigated using a series of symmetric, tetraalkylammonium counterions with methyl (TMA), ethyl (TEA), propyl (TPA), and butyl (TBA) pendent groups in addition to a sodium cation control. A detailed analysis of the aggregate structure was achieved by fitting the X-ray scattering profiles with a modified hard sphere model. Increasing the counterion sterics from sodium to TEA resulted in slight changes to the aggregates with some ionic groups present in the isoprene matrix. For the more sterically hindered TPA and TBA counterions, considerable disruption of the structure occurs. Using solid-state NMR, dynamic mechanical analysis, and rheology, the effect of the counterion sterics on the copolymer dynamics was determined. The larger counterions exhibited an increase in the dynamic moduli at high frequency while decreasing the dynamic moduli at lower frequencies in addition to possessing faster molecular dynamics. These two observations correspond to the incorporation of more ionic groups into the isoprene matrix and weakening of the dipole-dipole interactions, respectively. Lastly, binary mixtures of TMA and TBA ammonium counterions were employed in these P(I-ran-SS) copolymers. The P(I-ran-SS) ionomers with TMA:TBA weight ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 were prepared through solution blending. The SAXS profiles and Kinning-Thomas fitting showed only slight structural changes between 100:0 and 50:50, while major modification of the structure appears once the ratio reaches 75:25 and above. The alterations of the structure also indicated a mixed counterion aggregate structure. The linear viscoelastic characterization of the mixed counterion ionomers showed an increase in the polymer dynamics at low frequencies with increasing TBA weight percentages. Additionally, preliminary tensile tests were collected that showed increased mechanical properties with the stronger electrostatic interaction associated with TMA counterions. Thus, the structure and properties of these low Tg, amorphous ionomers can be specifically tuned by using multiple counterions. Through these studies, the role of both ion content and counterion identity on the structure and dynamics of low Tg, amorphous P(I-ran-SS) copolymers have been elucidated. Furthermore, ammonium-based cations have been shown to offer a versatile means to modify both the ion aggregate structure and interaction strength of an ionomer. Appropriate selection of the pendent groups and mixture of different counterions allow for the properties of the ionomer to be freely tuned.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Design of Polymerized Ionic Liquids written by Gabriel Eduardo Sanoja and published by . This book was released on 2016 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymerized ionic liquids are an emerging class of functional materials with ionic liquid moieties covalently attached to a polymer backbone. As such, they synergistically combine the structural hierarchy of polymers with the versatile physicochemical properties of ionic liquids. Unlike other ion-containing polymers that are typically constrained to high glass transition temperatures, polymerized ionic liquids can exhibit low glass transition temperatures due to weak electrostatic interactions even at high charge fractions. Promising applications relevant to electrochemical energy conversion and CO2 capture and sequestration have been demonstrated for polymerized ionic liquids, but a molecular design strategy that allows for elucidation of their structure-property relationships is yet to be developed. A combination of anionic polymerization, click chemistry, and ion metathesis allows for fine and independent control over polymer properties including the number of repeat units, fraction of ionic liquid moieties, composition, and architecture. This strategy has been exploited to elucidate the effect of lamellar domain spacing on the ionic conductivity of block copolymers based on hydrated protic polymerized ionic liquids. The conductivity relationship demonstrated in this study suggests that a mechanically robust material can be designed without compromising its ability to transport ions. The vast set of ion pair combinations in polymerized liquids provides a unique opportunity to develop functional materials where properties can be controlled with subtle changes in molecular structure via ion metathesis. We illustrate the case of a polymerized ionic liquid that combines the low toxicity and macromolecular dimensions of poly(ethylene glycol) with the magnetic functionality of ion pairs containing iron(III). This material can yield novel theranostic agents with controlled residence time within the human body, and paramagnetic functionality to enhance 1H nuclei relaxation rate required for medical imaging. Finally, the molecular design strategy is expanded to incorporate ion pairs based on metal-ligand coordination bonds between cations and imidazole moieties tethered to the polymer backbone. This illustrates a general approach for using chelating polymers with appropriate metal-ligand interactions to design high conductivity and tunable modulus polymer electrolytes.
Download or read book A Study of the Structure and Properties of Ion containing Polymers written by Yuan-Pang Samuel Ding and published by . This book was released on 1986 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Properties of Solid Ion containing Polymers written by Polymer Science Workshop and published by . This book was released on 1983 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymer Science and Engineering written by National Research Council and published by National Academies Press. This book was released on 1994-01-01 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are used in everything from nylon stockings to commercial aircraft to artificial heart valves, and they have a key role in addressing international competitiveness and other national issues. Polymer Science and Engineering explores the universe of polymers, describing their properties and wide-ranging potential, and presents the state of the science, with a hard look at downward trends in research support. Leading experts offer findings, recommendations, and research directions. Lively vignettes provide snapshots of polymers in everyday applications. The volume includes an overview of the use of polymers in such fields as medicine and biotechnology, information and communication, housing and construction, energy and transportation, national defense, and environmental protection. The committee looks at the various classes of polymersâ€"plastics, fibers, composites, and other materials, as well as polymers used as membranes and coatingsâ€"and how their composition and specific methods of processing result in unparalleled usefulness. The reader can also learn the science behind the technology, including efforts to model polymer synthesis after nature's methods, and breakthroughs in characterizing polymer properties needed for twenty-first-century applications. This informative volume will be important to chemists, engineers, materials scientists, researchers, industrialists, and policymakers interested in the role of polymers, as well as to science and engineering educators and students.
Download or read book Ion Containing Polymers written by A. Eisenberg and published by Elsevier. This book was released on 2012-12-02 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion-Containing Polymers: Physical Properties and Structure is Volume 2 of the series Polymer Physics. This book aims to fill in the gap in literature regarding the physical aspects of ion-containing polymers. A total of five chapters comprise this book. The Introduction (Chapter 1) generally deals with the application of ion-containing polymers, general classification, and the available works regarding the subject. Chapter 2 establishes the concepts of supermolecular structure and glass transitions in terms of the effects of ionic forces in polymers. These chapters provide the context in the discussion of viscoelastic properties of homopolymers and copolymers in Chapters 3 and 4. Finally, Chapter 5 tackles the configuration-dependent properties of ion-containing polymers. This volume will be of particular help to students in the field of physics and chemistry.
Download or read book Structure and Dynamics of Confined Polymers written by John J. Kasianowicz and published by Springer Science & Business Media. This book was released on 2002-07-31 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are essential to biology because they can have enough stable degrees of freedom to store the molecular code of heredity and to express the sequences needed to manufacture new molecules. Through these they perform or control virtually every function in life. Although some biopolymers are created and spend their entire career in the relatively large free space inside cells or organelles, many biopolymers must migrate through a narrow passageway to get to their targeted destination. This suggests the questions: How does confining a polymer affect its behavior and function? What does that tell us about the interactions between the monomers that comprise the polymer and the molecules that confine it? Can we design and build devices that mimic the functions of these nanoscale systems? The NATO Advanced Research Workshop brought together for four days in Bikal, Hungary over forty experts in experimental and theoretical biophysics, molecular biology, biophysical chemistry, and biochemistry interested in these questions. Their papers collected in this book provide insight on biological processes involving confinement and form a basis for new biotechnological applications using polymers. In his paper Edmund DiMarzio asks: What is so special about polymers? Why are polymers so prevalent in living things? The chemist says the reason is that a protein made of N amino acids can have any of 20 different kinds at each position along the chain, resulting in 20 N different polymers, and that the complexity of life lies in this variety.
Download or read book Structure and Properties of Solid Ion containing Polymers written by Polymer Science Workshop. Polymer Science Workshop and published by . This book was released on 1982 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Properties of Solid Ion containing Polymers written by Michel Pineri and published by . This book was released on 1983 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure property Studies of Ion containing Polymers written by Richard Swee-Chye Yeo and published by . This book was released on 1976 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Covalent Organic Frameworks written by Atsushi Nagai and published by CRC Press. This book was released on 2019-12-19 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rational synthesis of extended arrays of organic matter in bulk, solution, crystals, and thin films has always been a paramount goal of chemistry. The classical synthetic tools to obtain long-range regularity are, however, limited to noncovalent interactions, which usually yield structurally more random products. Hence, a combination of porosity and regularity in organic covalently bonded materials requires not only the design of molecular building blocks that allow for growth into a nonperturbed, regular geometry but also a condensation mechanism that progresses under reversible, thermodynamic, self-optimizing conditions. Covalent organic frameworks (COFs), a variety of 2D crystalline porous materials composed of light elements, resemble an sp2-carbon-based graphene sheet but have a different molecular skeleton formed by orderly linkage of building blocks to constitute a flat organic sheet. COFs have attracted considerable attention in the past decade because of their versatile applications in gas storage and separation, catalysis, sensing, drug delivery, and optoelectronic materials development. Compared to other porous materials, COFs allow for atomically precise control of their architectures by changing the structure of their building blocks, whereby the shapes and sizes of their pores can be well-tuned. Covalent Organic Frameworks is a compilation of different topics in COF research, from COF design and synthesis, crystallization, and structural linkages to the theory of gas sorption and various applications of COFs, such as heterogeneous catalysts, energy storage (e.g., semiconductors and batteries), and biomedicine. This handbook will appeal to anyone interested in nanotechnology and new materials of gas adsorption and storage, heterogeneous catalysts, electronic devices, and biomedical devices.
Download or read book Designing Ion containing Polymers for Facile Ion Transport written by Wenjuan Liu and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of polymer electrolytes with sufficient ionic conductivity will enable the design of flexible, efficient Li ion batteries and is also of primary interest for actuators, alternative battery membranes, and within the membrane-electrode assembly of fuel cells. Optimization of ionic polymer (ionomer) compositions will provide single-ion conductors with the required conductivity for energy conversion applications, and further, that the identification of optimal compositions can be facilitated. Ab initio methods use the first principles of quantum mechanics to determine the electronic state of a system, and can therefore quantify interaction energies between species without parameterization from experimental studies. A bottom-up design strategy based on ab initio calculations can be rapidly applied to a wide variety of anions and cations in different polar media, enabling a detailed understanding of ion interactions and solvation by polar groups, in the aim of suggesting anion, polar side group, backbone combinations worthy of synthesis. Collaboration with on-going experimental efforts on ionomer synthesis and dielectric spectroscopy that measures populations of conducting ions and ion pairs, will allow for realization of ionomer compositions suggested by theory, as well as serve to validate models.
Download or read book Structure property Studies of Ion containing Polymers written by Yeo, Richard S. (Richard Swee-Chye) and published by 1976 [c1977]. This book was released on 1976 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical Properties and Structure of Ion Containing Polymers written by A. Eisenberg and published by . This book was released on 1984 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive study of the properties of ionomers has been performed. One phase involved structure-property relations in styrene ionomers in which the placement of the ions, their type, and their concentration was varied systematically. Other variables involved changes in chain geometry. Also, a method was developed for compatibilizing otherwise immiscible polymers involving ionic interactions and finally, some studies were performed on Nafion membranes. (Author).
Download or read book Thin Film Dynamics of Ion containing Polymers Under Confinement written by Douglas Kushner and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Expanding this knowledge will lead to the development of materials that increase the performance of fuel cell devices by providing a more intimate image of how these polymers will perform in the catalyst layer, and the ideas developed here can be extended to new types of materials used in various applications.
Download or read book Technology for Large Space Systems written by and published by . This book was released on 1989 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
