Download or read book Self assembly and Gold Nanoparticle Cross linking of Stimuli responsive Block Copolymers Synthesized by Reversible Addition fragmentation Chain Transfer Polymerization written by Adam Eugene Smith and published by . This book was released on 2010 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Aqueous Solution Studies of Stimuli responsive Block Copolymers Synthesized by Reversible Addition fragmentation Chain Transfer Polymerization written by Anthony Joseph Convertine and published by . This book was released on 2006 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Polymerization Reactions written by Wayne F. Reed and published by John Wiley & Sons. This book was released on 2014-01-21 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers new strategies to optimize polymer reactions With contributions from leading macromolecular scientists and engineers, this book provides a practical guide to polymerization monitoring. It enables laboratory researchers to optimize polymer reactions by providing them with a better understanding of the underlying reaction kinetics and mechanisms. Moreover, it opens the door to improved industrial-scale reactions, including enhanced product quality and reduced harmful emissions. Monitoring Polymerization Reactions begins with a review of the basic elements of polymer reactions and their kinetics, including an overview of stimuli-responsive polymers. Next, it explains why certain polymer and reaction characteristics need to be monitored. The book then explores a variety of practical topics, including: Principles and applications of important polymer characterization tools, such as light scattering, gel permeation chromatography, calorimetry, rheology, and spectroscopy Automatic continuous online monitoring of polymerization (ACOMP) reactions, a flexible platform that enables characterization tools to be employed simultaneously during reactions in order to obtain a complete record of multiple reaction features Modeling of polymerization reactions and numerical approaches Applications that optimize the manufacture of industrially important polymers Throughout the book, the authors provide step-by-step strategies for implementation. In addition, ample use of case studies helps readers understand the benefits of various monitoring strategies and approaches, enabling them to choose the best one to match their needs. As new stimuli-responsive and "intelligent" polymers continue to be developed, the ability to monitor reactions will become increasingly important. With this book as their guide, polymer scientists and engineers can take full advantage of the latest monitoring strategies to optimize reactions in both the lab and the manufacturing plant.
Download or read book Novel Stimuli responsive Block Copolymers Via Reversible Addition fragmentation Chain Transfer Polymerization written by Brent Sterling Sumerlin and published by . This book was released on 2003 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hierarchical Self assembly of Nanoparticles Using Reversible Addition fragmentation Chain transfer Block Copolymers written by Fraser Burns and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hierarchical self-assembly of cadmium based quantum dots through the use of RAFT block copolymers have been investigated. The formation of cadmium selenide quantum dots within the core of tetrablock RAFT copolymers in three different solvents, dioxane, THF and DMF was investigated experimentally and computationally. It was determined that aggregation of the PAA core-forming blocks prevented the formation of stable dispersions of the CdSe quantum dots in DMF and THF, while dioxane was found to be a suitable solvent. The cadmium selenide quantum dots exhibit a near band-edge emission centered at 520 nm with a hydrodynamic diameter of 20 nm. The assembly of RAFT copolymer encapsulated cadmium sulfide quantum dots with gold nanoparticles was explored. It was determined that with increasing concentration of gold nanoparticles, there was an increase in emission amplification. Subsequent self-assembly into large compound micelles with PS-b-PAA block copolymer was investigated and determined to form large, water-soluble compound micelles.
Download or read book Single Chain Polymer Nanoparticles written by José A. Pomposo and published by John Wiley & Sons. This book was released on 2017-08-18 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first book on this important and emerging topic presents an overview of the very latest results obtained in single-chain polymer nanoparticles obtained by folding synthetic single polymer chains, painting a complete picture from synthesis via characterization to everyday applications. The initial chapters describe the synthetics methods as well as the molecular simulation of these nanoparticles, while subsequent chapters discuss the analytical techniques that are applied to characterize them, including size and structural characterization as well as scattering techniques. The final chapters are then devoted to the practical applications in nanomedicine, sensing, catalysis and several other uses, concluding with a look at the future for such nanoparticles. Essential reading for polymer and materials scientists, materials engineers, biochemists as well as environmental chemists.
Download or read book Synthesis and Characterization of Stimuli Responsive Block Copolymers Self assembly Behavior and Applications written by Michael Duane Determan and published by . This book was released on 2006 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water-soluble stimuli responsive block copolymers are a rapidly emerging class of materials with great potential in biomedical and technological applications. In this work a novel class of pentablock copolymers are synthesized via atom transfer radical polymerization techniques and their stimuli-responsive self-assembly properties are characterized. Aqueous solutions of these materials are observed to form micelles and hydrogels in response to changes in both temperature and pH. Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron and X-ray scattering (SANS and SAXS) techniques are used to investigate the nanoscale structures formed by these pentablock copolymers in solution. The gel structure and mechanical properties are investigated with SANS and rheological techniques. The multi-responsive properties of these materials are utilized to formulate a stimuli responsive drug delivery formulation that exhibits thermoreversible gelation and pH dependent release rate of model drugs.
Download or read book Aqueous Reversible Addition fragmentation Chain Transfer Polymerization of Functional Monomers and Their Incorporation Into Stimuli responsive Amphiphilic Block Copolymers written by Bradley Steward Lokitz and published by . This book was released on 2007 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Hydrogel Forming Thermo responsive Block Copolymers of Increasing Structural Complexity written by Anna Miasnikova and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the synthesis and characterization of stimuli-responsive polymers made by reversible addition-fragmentation chain transfer (RAFT) polymerization and the investigation of their self-assembly into "smart" hydrogels. In particular the hydrogels were designed to swell at low temperature and could be reversibly switched to a collapsed hydrophobic state by rising the temperature. Starting from two constituents, a short permanently hydrophobic polystyrene (PS) block and a thermo-responsive poly(methoxy diethylene glycol acrylate) (PMDEGA) block, various gelation behaviors and switching temperatures were achieved. New RAFT agents bearing tert-butyl benzoate or benzoic acid groups, were developed for the synthesis of diblock, symmetrical triblock and 3-arm star block copolymers. Thus, specific end groups were attached to the polymers that facilitate efficient macromolecular characterization, e.g by routine 1H-NMR spectroscopy. Further, the carboxyl end-groups allowed functionalizing the various polymers by a fluorophore. Because reports on PMDEGA have been extremely rare, at first, the thermo-responsive behavior of the polymer was investigated and the influence of factors such as molar mass, nature of the end-groups, and architecture, was studied. The use of special RAFT agents enabled the design of polymer with specific hydrophobic and hydrophilic end-groups. Cloud points (CP) of the polymers proved to be sensitive to all molecular variables studied, namely molar mass, nature and number of the end-groups, up to relatively high molar masses. Thus, by changing molecular parameters, CPs of the PMDEGA could be easily adjusted within the physiological interesting range of 20 to 40°C. A second responsivity, namely to light, was added to the PMDEGA system via random copolymerization of MDEGA with a specifically designed photo-switchable azobenzene acrylate. The composition of the copolymers was varied in order to determine the optimal conditions for an isothermal cloud point variation triggered by light. Though reversible light-induced solubility changes were achieved, the differences between the cloud points before and after the irradiation were small. Remarkably, the response to light differed from common observations for azobenzene-based systems, as CPs decreased after UV-irradiation, i.e with increasing content of cis-azobenzene units. The viscosifying and gelling abilities of the various block copolymers made from PS and PMDEGA blocks were studied by rheology. Important differences were observed between diblock copolymers, containing one hydrophobic PS block only, the telechelic symmetrical triblock copolymers made of two associating PS termini, and the star block copolymers having three associating end blocks. Regardless of their hydrophilic block length, diblock copolymers PS11 PMDEGAn were freely flowing even at concentrations as high as 40 wt. %. In contrast, all studied symmetrical triblock copolymers PS8-PMDEGAn-PS8 formed gels at low temperatures and at concentrations as low as 3.5 wt. % at best. When heated, these gels underwent a gel-sol transition at intermediate temperatures, well below the cloud point where phase separation occurs. The gel-sol transition shifted to markedly higher transition temperatures with increasing length of the hydrophilic inner block. This effect increased also with the number of arms, and with the length of the hydrophobic end blocks. The mechanical properties of the gels were significantly altered at the cloud point and liquid-like dispersions were formed. These could be reversibly transformed into hydrogels by cooling. This thesis demonstrates that high molar mass PMDEGA is an easily accessible, presumably also biocompatible and at ambient temperature well water-soluble, non-ionic thermo-responsive polymer. PMDEGA can be easily molecularly engineered via the RAFT method, implementing defined end-groups, and producing different, also complex, architectures, such as amphiphilic triblock and star block copolymers, having an analogous structure to associative telechelics. With appropriate design, such amphiphilic copolymers give way to efficient, "smart" viscosifiers and gelators displaying tunable gelling and mechanical properties.
Download or read book Self Assembly of Polymers written by Dmitry Volodkin and published by MDPI. This book was released on 2020-04-22 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, polymer self-assembly has become extremely attractive for both biological (drug delivery, tissue engineering, scaffolds) and non-biological (packaging, semiconductors) applications. In nature, a number of key biological processes are driven by polymer self-assembly, for instance protein folding. Impressive morphologies can be assembled from polymers thanks to a diverse range of interactions involved, e.g., electrostatics, hydrophobic, hots-guest interactions, etc. Both 2D and 3D tailor-made assemblies can be designed through modern powerful techniques and approaches such as the layer-by-layer and the Langmuir-Blodgett deposition, hard and soft templating. This Special Issue highlights contributions (research papers, short communications, review articles) that focus on recent developments in polymer self-assembly for both fundamental understanding the assembly phenomenon and real applications.
Download or read book Mambo mortale written by Landesstelle Jugendschutz and published by . This book was released on 1990 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanostructured Polymer Blends written by Gity Mir Mohamad Sadeghi and published by Elsevier Inc. Chapters. This book was released on 2013-11-28 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers (BCPs) consist of two or more chemically different polymers connected covalently, and are polymer alloys. Due to their thermodynamic incompatibility and chain connectivity, the phase separation between two (or more) blocks occurs only in a tens of nanometers range. Nanostructures are based on block copolymer self-assembly. They are functional nanomaterials less than 100nm in size and have received extensive scientific and technological attention due to their potential applications in electronic, biomedical, and optical materials. This chapter examines a variety of different synthetic strategies for preparation of linear diblock copolymers by anionic polymerization. Triblocks can be synthesized according to an appropriate synthetic pathway, depending on the monomers used and their sequence in the triblock chain. Nonlinear block copolymers including star block copolymers, graft copolymers, miktoarm star copolymers, cyclic block copolymers, and other complex architectures are explained. Microphase separation drives BCPs to self-assemble, resulting in ordered nanostructures, including spheres, cylinders, gyroids, and lamellae, depending on the composition of the BCP. In nanotechnology, self-assembly (SA) underlies various types of molecular structures built from nanoparticles, nanotubes, or nanorods. Supramolecular structures generated from amphiphilic block copolymers are characterized by a slow rate of intermicellar chain exchange which makes them interesting for a variety of applications. Basic principles of self-assembly and micellization of block copolymers in dilute solution, methods for stabilization of the macromolecular aggregates, are discussed. Stabilized nanoparticles, the so-called “smart materials,” which show responses to environmental changes (pH, temperature, ionic strength, etc.), are presented with a focus on their applications.
Download or read book Block Copolymers in Solution written by Ian W. Hamley and published by John Wiley & Sons. This book was released on 2005-12-13 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique text discusses the solution self-assembly of block copolymers and covers all aspects from basic physical chemistry to applications in soft nanotechnology. Recent advances have enabled the preparation of new materials with novel self-assembling structures, functionality and responsiveness and there have also been concomitant advances in theory and modelling. The present text covers the principles of self-assembly in both dilute and concentrated solution, for example micellization and mesophase formation, etc., in chapters 2 and 3 respectively. Chapter 4 covers polyelectrolyte block copolymers - these materials are attracting significant attention from researchers and a solid basis for understanding their physical chemistry is emerging, and this is discussed. The next chapter discusses adsorption of block copolymers from solution at liquid and solid interfaces. The concluding chapter presents a discussion of selected applications, focussing on several important new concepts. The book is aimed at researchers in polymer science as well as industrial scientists involved in the polymer and coatings industries. It will also be of interest to scientists working in soft matter self-assembly and self-organizing polymers.
Download or read book Block Copolymers written by Nikos Hadjichristidis and published by John Wiley & Sons. This book was released on 2003-04-28 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers may be classified as either homopolymers, consisting of one single repeating unit, or copolymers, consisting of two or more distinct repeating units. Block copolymers contain long contiguous blocks of two or more repeating units in the same polymer chain. Covering one of the hottest topics in polymer chemistry, Block Copolymers provides a coherent overview of the synthetic routes, physical properties, and applications of block copolymers. This pioneering text provides not only a guideline for developing synthetic strategies for creating block copolymers with defined characteristics, but also a key to the relationship between the physical properties of block copolymers and the structure and dynamics of materials. Covering features of the chemistry and physics of block copolymers that are not found in comparable texts, Block Copolymers illustrates the structure-activity relationship of block copolymers and offers suggestions for the design of specific applications. Divided into five sections-Block Copolymers includes chapters on: * Block Copolymers by Chemical Modification of Precursor Polymers * Nonlinear Block Copolymers * Adsorption of Block Copolymers at Solid-Liquid Interfaces * Theory of Block Copolymer Segregation * Phase Transformation Kinetics * Block Copolymer Morphology * Block Copolymer Dynamics Polymer chemists, physicists, chemical engineers, and materials scientists, as well as graduate students in polymer science, will find Block Copolymers to be an invaluable text.
Download or read book Synthesis Self Assembly and Modification of Poly vinylpyridine Based Block Copolymers for the Creation of Well Ordered Charged Nanostructures written by Brandon Aubrey Fultz and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation investigates the use of block copolymer self-assembly to create nanostructures with unique domain properties. Precise control over nanoscale feature size and properties of materials has become increasingly more important to keep up the ever-decreasing size of technology. Bottom-up approaches using block copolymers has been progressively more attractive due to their ability to autonomously self-assembly into an array of complex morphologies with features sizes as small as 2-3 nanometers. Modifications of these systems has generally been limited to only one domain as the processes under which modifications are carried out generally result in the disruption or destruction of the underlying morphology. We originally set out to create a block polymer system containing poly(vinylpyridine) (PVP) segments which can undergo several transformations such as protonation, metal coordination, or quaternization. By coupling PVP segments with poly(tert-butyl methacrylate), we believed that a well-ordered charged mosaic containing segregated opposite charges could be created without disruption of the underlying morphology. Thin films of hexagonally packed P4VP cylinders were self-assembled perpendicular to the surface and subsequently treated with bromoethane vapor at various durations to quaternize pyridinyl nitrogens. The PtBMA matrix was then partially hydrolyzed to poly(methacrylic acid), PMAA, through HCl vapor treatment followed by neutralization by brief submersion in KOH solution. Using techniques such as AFM, contact angle testing, and ToF-SIMS, we were able to determine the success of these transformations as well as methodologies in which structural morphology was maintained. An additional exploration into the use of tris(trimethylsilyl)silane (TTMSS) as non-toxic alternative to tin hydrides using only light was investigated as a method to remove reversible addition-fragmentation transfer (RAFT) chain transfer agents. As the end group removal from PVP polymers derived from RAFT has to our knowledge never been reported, we felt that these results would be invaluable to the scientific community due to the ubiquitous use of PVP in many systems. Not only was TTMSS found to be an effective reagent for RAFT removal of PVP polymers, it was also found to be effective for the removal of RAFT end groups from polystyrene which has been generally reported in literature to be difficult due to the stability of the benzyl radical. Reactions were found to be complete for most polymers in less than 2 hours whereas, other reported reagents typically took 24 hours or as much as 1 week.
Download or read book Polymer Synthesis written by Elaheh Kowsari and published by . This book was released on 2011-10 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an overview of research on advanced synthesis polymers over the past decade. This special issue, contributed by various authors, focuses on recent advances of the field, which handle the cutting-edge aspects of the advanced technology. The contributions in these twelve chapters summarise some major efforts in this area.
Download or read book New Stimuli responsive Block Random Copolymers and Their Aggregation written by Mohammad T. Savoji and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
