Download or read book Morphological Control of Block Copolymer Aggregates in Aqueous Solutions written by Nichole Fairley and published by . This book was released on 2009 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: In aqueous media, amphiphilic block copolymers spontaneously self-assemble into nano-sized core-shell structures, termed block copolymer micelles. The ability for researchers to reliably reproduce morphologies in a controlled manner is of great interest because of the potential advantages and applications of copolymer aggregates with varying morphologies. This thesis describes the physico-chemical characteristics of polymer micelles, as well as the parameters which influence morphology in aqueous solution. The purpose of this research was to study the morphology of the amphiphilic block copolymer PEG5000-b-PCL4100 in aqueous solution. It was found that the amphiphilic block copolymer PEG5000-b-PCL 4100 could form long rod-like, short rod-like or spherical aggregates by controlling the copolymer concentration, or through the addition of a PEG-phospholipid to the copolymer. Overall, this research clearly demonstrates the ability to control block copolymer morphology which will inevitably play a pivotal role in the use of non-spherical micelles for pharmaceutical applications.
Download or read book Soft Matter Characterization written by Redouane Borsali and published by Springer Science & Business Media. This book was released on 2008-07-28 with total page 1490 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2-volume set includes extensive discussions of scattering techniques (light, neutron and X-ray) and related fluctuation and grating techniques that are at the forefront of this field. Most of the scattering techniques are Fourier space techniques. Recent advances have seen the development of powerful direct imaging methods such as atomic force microscopy and scanning probe microscopy. In addition, techniques that can be used to manipulate soft matter on the nanometer scale are also in rapid development. These include the scanning probe microscopy technique mentioned above as well as optical and magnetic tweezers.
Download or read book Manipulating the Morphologies of Poly vinyl Alcohol Block Copolymer Surfactants written by and published by . This book was released on 2014 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphiphilic block copolymers (ABCs) are macromolecules containing well-defined hydrophilic and hydrophobic segments that self-assemble into nanoscale aggregates such as spherical and cylindrical micelles and vesicles, when dispersed in block-selective solvents. ABCs possess a miniscule critical micelle concentration, which results in kinetically trapped and persistent assemblies in solution with slow chain exchange between aggregates. This makes them useful as rheological modifiers for personal care products, enhanced oil recovery, and drug delivery formulations. Their utility in many of these applications is crucially dependent on the ability to control the micellar morphologies that they adopt in selective solvents. Triggering ABC micellar morphological transformations, i.e. from spherical to cylindrical micelles, is important for generating "on-demand" stimuli-responsive morphologies that control the aggregate morphology and the bulk solution properties in any given application. In this thesis, we develop the straightforward synthesis of biodegradable and biocompatible ABCs comprised of poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVA), with narrow molecular distributions and variable yet well-defined compositions. These block copolymer amphiphiles readily form spherical micelles in aqueous dispersions. We demonstrate that the addition of a water-soluble poly(ethylene oxide) (PEO) homopolymer to these dispersions results in a rapid transformation of these spherical micelles into cylindrical micelles. Dilution of these cylindrical micelles with water induces their reversion to spherical micelles. Our results indicate that the reversible morphology change depends sensitively on the PEO homopolymer concentration and molecular weight, as well as the length of the PVA corona block of the micelles. Through a series of quantitative 1H NMR studies, we found that the preferential partitioning of PEO homopolymer into the PVAc micellar core drives this morphological transformation. We also investigated the aqueous micellar self-assembly of non-covalent amphiphilic block copolymers (NC-ABCs) derived from complexation of an anionic gemini dicarboxylate surfactant (Na-96) to poly(ethylene oxide)-block-poly(2-(methacryloyloxy)-ethyltrimethylammonium chloride) (mPEO-b-qPDMAEMAxCl) (x = 48 or 110) at charge stoichiometries of [qDMAEMA+]:[COO-] = 1:1 and 1:0.5. Our results demonstrate that these polymer/surfactant complexes adopt rod-like conformations, the liquid crystallinity of which drives the formation of facetted vesicles and hollow tubular micelles.
Download or read book Block Copolymers in Solution written by Ian W. Hamley and published by John Wiley & Sons. This book was released on 2005-09-02 with total page 312 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 Self Organized Nanostructures of Amphiphilic Block Copolymers II written by Axel H.E. Müller and published by Springer Science & Business Media. This book was released on 2011-08-13 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block Copolymer Surfactant Mixtures in Aqueous Solution: Can we Achieve Size and Shape Control by Co-Micellization?, by Thomas Hellweg; Non-ionic Thermoresponsive Polymers in Water, by Vladimir Aseyev, Heikki Tenhu and Françoise Winnik; From Coordination Polymers to Hierarchical Self-Assembled Structures, by Yun Yan, Arie de Keizer, Martien A. Cohen Stuart and Nicolaas A. M. Besseling; Processes of Ordered Structure Formation in Polypeptide Thin Film Solutions, by Ioan Botiz, Helmut Schlaad and Günter Reiter; Amphiphilic Polymers at Interfaces, by Katarzyna Kita-Tokarczyk, Mathias Junginger, Serena Belegrinou and Andreas Taubert;
Download or read book Polymer Morphology written by Qipeng Guo and published by John Wiley & Sons. This book was released on 2016-05-16 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: With a focus on structure-property relationships, this book describes how polymer morphology affects properties and how scientists can modify them. The book covers structure development, theory, simulation, and processing; and discusses a broad range of techniques and methods. • Provides an up-to-date, comprehensive introduction to the principles and practices of polymer morphology • Illustrates major structure types, such as semicrystalline morphology, surface-induced polymer crystallization, phase separation, self-assembly, deformation, and surface topography • Covers a variety of polymers, such as homopolymers, block copolymers, polymer thin films, polymer blends, and polymer nanocomposites • Discusses a broad range of advanced and novel techniques and methods, like x-ray diffraction, thermal analysis, and electron microscopy and their applications in the morphology of polymer materials
Download or read book Concise Encyclopedia of Biomedical Polymers and Polymeric Biomaterials written by Munmaya Mishra and published by CRC Press. This book was released on 2017-08-16 with total page 1800 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Concise Encyclopedia of Biomedical Polymers and Polymeric Biomaterials presents new and selected content from the 11-volume Biomedical Polymers and Polymeric Biomaterials Encyclopedia. The carefully culled content includes groundbreaking work from the earlier published work as well as exclusive online material added since its publication in print. A diverse and global team of renowned scientists provide cutting edge information concerning polymers and polymeric biomaterials. Acknowledging the evolving nature of the field, the encyclopedia also features newly added content in areas such as tissue engineering, tissue repair and reconstruction, and biomimetic materials.
Download or read book Biomineralization II written by Kensuke Naka and published by Springer Science & Business Media. This book was released on 2007 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series presents critical reviews of the present position and future trends in modern chemical research. The short and concise reports on chemistry are each written by world renowned experts. This series is still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com.
Download or read book Aqueous Mixtures of Block Copolymer Surfactants written by Sumeet Jain and published by . This book was released on 2005 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetics and Mechanisms of Morphological Transitions in Block Copolymer Aggregates and Sodium Dodecyl Sulfate as a Morphogenic Agent written by Susan Elizabeth Burke and published by . This book was released on 2001 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The kinetic and mechanistic details involved in the morphological transitions occurring in aggregates prepared from the copolymer polystyrene-b-poly(acrylic acid) (PS-b-PAA) in dioxane-water mixtures and the ability of sodium dodecyl sulfate to induce architectural changes in these aggregates are described in this dissertation. The kinetics of the sphere-to-rod, rod-to-sphere, and vesicle-to-rod transitions were determined by following the change in the solution turbidity as a function of time after the transitions were induced by a sudden jump in one of the solvent components of the system. The kinetics of each transition was explored as a function of the initial solvent composition, the magnitude of the solvent content jump, and the initial polymer concentration. In another study, the amphiphile, sodium dodecyl sulfate (SDS), was found to induce morphological transitions in the copolymer aggregates at lower water contents than those required in the absence of surfactant. The effect was studied as a function of SDS concentration, solvent composition, and copolymer concentration." --
Download or read book Nano aggregate of Block Copolymers in Aqueous Solutions written by Anil Khanal and published by . This book was released on 2011-11 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Papers Presented at the Meeting written by American Chemical Society. Division of Polymer Chemistry and published by . This book was released on 2000 with total page 948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis Characterization and Self assembly of Amphiphilic Block Copolymers written by Xiaojun Wang and published by . This book was released on 2012 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a review on state-of-the-art research of well-defined charged block copolymers, including synthesis, characterization, bulk morphology and self-assembly in aqueous solution of amphiphilic block polyelectrolytes. In Chapter 1, as a general introduction, experimental observations and theoretical calculations devoted towards understanding morphological behavior in charged block copolymer systems are reviewed along with some of the new emerging research directions. Further investigation of charged systems is urged in order to fully understand their morphological behavior and to directly target structures for the tremendous potential in technological applications. Following this background, in Chapters 2, 3, 4 and 5 are presented the design and synthesis of a series of well-defined block copolymers composed of charged and neutral block copolymers with full characterization: sulfonated polystyrene-b-fluorinated polyisoprene (sPS-b-fPI) and polystyrene-b-sulfonated poly(1,3-cyclohexadiene) (PS-b-sPCHD). Their bulk morphological behaviors in melts and self-assembly of sPS-b-fPI, PS-b-sPCHD in water were investigated. Some unique behaviors of sPS-b-fPI were discovered. The mechanisms for formation of novel nanostructures in aqueous solution are discussed in details in Chapter 4. Spherical and vesicular structures were formed from strong electrolyte block copolymers, e.g. PS-bsPCHD. Detailed light scattering and transmission electron microscopy were applied to characterize these structures. The abnormal formation of vesicles as well as microstructure effects on self-assembly is discussed in Chapter 5. In Chapter 6, we describe the successful synthesis of a well-defined acid-based block copolymers containing polyisoprene while maintaining the integrity of the functionality (double bonds) of polyisoprene. A general purification method is also presented in order to remove homo polyisoprene, polystyrene, and PS-b-PI in the di-, and tri-block copolymers. The self-assembly of PS-b-PI-b-PAA triblock terpolymers was studied in order to form multicompartmental structures in aqueous environments. In the last Chapter 7, detailed synthesis and characterization of a novel conjugate: poly(L-leucine) grafted hyaluronan (HA) (HA-g-PLeu) are presented. This work describes a new method to synthesize HA-g-PLeu via a "grafting onto" strategy. Due to the amphiphilic nature of this graft copolymers, a "local network" formed by self-assembly which was characterized by atomic force microscopy and light scattering. The secondary structure of the polypeptide was revealed by circular dichroism.
Download or read book Smart Membranes and Sensors written by Annarosa Gugliuzza and published by John Wiley & Sons. This book was released on 2014-09-19 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the reader to use synergistically the concepts of membranes and sensors materials. It contains insightful contributions from leading scientists working in both the fields. The focus is on the fabrication of smart membranes from sensor materials and related impact on many technologically sophisticated areas such as telemedicine, microfluidics, drug delivery targeting, (bio)separation, labs-on-a-chip, textiles, power storage and release, environment monitoring, agro-food safety, cosmetics, architecture, automotive and so on. This book covers various topics, including the choice of materials and techniques for assembling responsive membranes with ability to transport mass, energy and signals on demand; the reader will find through the book an extensive description of the best techniques used to monitor molecular scale events, which are regarded as responsible for the smartness of multifunctional objects and for the conversion of chemical signals into optical, electrical, thermal and mechanical responses. The reader is encouraged to use this cross-disciplinary discussion for his own research. Chemical, biological and physical concepts, expressed through the book, contribute to form a common language, which will allow the reader to discover causes for reflection and innovation, measuring how smart objects with desired properties can be tailored from exiting materials and used flexibly for different developed applications. Specifically: This book deals with materials smartness and suitable techniques to assemble and characterize them in sensor-like membranes. This book shows how ultra-smart functional devices can be accomplished by using traditional raw materials. This book describes particular key events, which control 'sense to react and adapt' mechanisms. The potential of sensor-like membranes in some key strategic fields is examined with particular emphasis on biomedicine, food and textiles markets. The benefits arising from the use of smart membranes are analysed in terms of life quality, safety, and innovation.
Download or read book Self assembled Polystyrene block poly ethylene Oxide PS b PEO Micelle Morphologies in Solution written by Prachur Bhargava and published by . This book was released on 2007 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research, we have investigated the self-assembly behavior of the amphiphilic diblock copolymer polystyrene-b-poly(ethylene oxide) PS962-b-PEO227 in DMF/water and DMF/acetonitrile mixtures. We have used solution conditions, namely copolymer concentration, solvent composition and temperature to control the morphology of aggregates. With increasing the water concentration in the DMF/water or the acetonitrile concentration in the DMF/acetonitrile system, the micelle morphology observed in transmission electron microscopy changed from spheres to worm-like cylinders and then, to vesicles. Critical micelle concentrations were determined by static light scattering. Morphological diagrams were constructed from the study of the micelle morphology changes in different copolymer concentrations. Based on the observations of morphological reversibility and annealing experiments, these two morphological diagrams were proven to be in thermodynamic equilibrium. Although the trend in morphological changes was identical in these two systems, there were remarkable differences in the morphological diagrams of PS962-b-PEO227. At higher copolymer concentrations a 'worm-network', which led to an order of magnitude increase in the inherent viscosity of the colloidal system was formed only in the DMF/water system.4 The percentage of selective solvent required to induce morphological changes was much higher in case of DMF/acetonitrile system. The driving force for these morphological changes was understood to approach micelle free energy minimization. Approximate micelle free energy calculations confirmed that the free energy decreases as the morphology changes from spheres to worm-like cylinders and then to vesicles with an increase in the selective solvent concentrations, and is dominated by the free energy of the interface. Further insight into the thermodynamic nature of morphological changes was achieved by inducing temperature driven morphological changes in DMF/water mixtures. With increasing the temperature, changes in the morphology from vesicles to worm-like cylinders and then to spheres were observed. Cooling the system back to room temperature regenerated the vesicle morphology indicating that the morphological changes are reversible. No hysteresis was observed in the morphological transitions during heating and cooling, indicating that the system is in thermodynamic equilibrium. The critical micellization temperatures and critical morphological transition temperatures were determined by turbidity measurements and were found to be dependent on the copolymer concentration and water content in the DMF/water mixture. The driving force for these morphological changes was understood to be reduction in the free energy of the corona and interfacial energy, which resulted in minimization of the micelle free energy.
Download or read book Polymer Micelles written by Shin-ichi Yusa and published by MDPI. This book was released on 2018-04-20 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Polymer Micelles" that was published in Polymers
Download or read book Kinetics and Mechanisms of Morphological Transitions in Block Copolymer Aggregates and Sodium Dodecyl Sulfate as a Morphogenic Agent microform written by Susan Elizabeth Burke and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2001 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
