Download or read book Tuning Melt phase Morphology in Block Copolymers Using Block Dispersity written by and published by . This book was released on 2014 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers non-linearly combine the properties of two different homopolymers into a single material, by virtue of the connectivity between the two distinct homopolymer segments. Their microphase separation at the nanoscale leads to the formation of interesting and useful microstructures, such as spheres and cylinders ordered on regular lattices with high degrees of long-range order. The advent of newer controlled radical and tandem polymerization techniques enables the enchainment of an ever increasing number of functional monomers with new properties, yet these techniques typically result in copolymers with broader molecular weight dispersities. A thorough understanding of the morphological consequences of increased molecular weight dispersity in one or more segments in a block copolymer will enable the development of new materials incorporating unusual monomers with new chemical functionalities and properties. Herein, we describe the synthesis and characterization of a library of poly(lactide-b-1,4-butadiene-b-lactide) (LBL) triblock copolymer samples with broad dispersity center segments, and we compare their melt-phase self-assembly behavior to previously reported polydisperse SBS triblock copolymers. Based on these comparisons, we rationalize the dramatically different behaviors of the two systems in terms of specific chain packing arrangements that depend upon the degree of chemical incompatibility of the copolymer system. In an attempt to mimic the most important molecular heterogeneities of continuously polydisperse copolymers as identified by our studies, we designed bidisperse blends of triblock copolymers and studied their morphological and uniaxial mechanical properties. As with continuously polydisperse copolymers, these blends also adopted bicontinuous morphologies with substantial mechanical toughness. In the latter part of this thesis, we investigate the influence of macromolecular dispersity on the macrophase separation behavior of mixtures of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) co-dissolved in water. The location of the concentration-dependent phase boundary, which separates the phase separated and phase mixed regions, is shown to depend on both the average molecular weight and dispersity of the polymeric components. Colloidal and copolymer surfactant additives are further shown to improve ATPS emulsion stability at higher temperatures and to mitigate emulsion coarsening.
Download or read book Manipulating Phase Behavior in Block Copolymers Using Polydispersity written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of polydispersity, or broad molecular weight distributions, on the phase behavior of block copolymer melts and thin films are systematically explored. Linear AB diblock, ABA triblock, and BAB triblock copolymers are synthesized with continuous polydispersity in the B block (Mw/Mn 8́ơ 1.70́32.0) and relatively monodisperse A blocks (Mw/Mn 8́ơ 1.10́31.3) to understand how the self0́3assembly of polydisperse block copolymers can be altered with chain architecture and block connectivity. Broad dispersity in the M block of poly(styrene0́3b0́3methyl methacrylate) (SM) diblock copolymer melts induces domain dilation and morphological transitions to higher M block volume compositions with respect to predictions for monodisperse SM diblock copolymers. A comparison between poly(styrene0́3b0́31,40́3butadiene0́3b0́3styrene) triblock copolymers (SBS) with mid0́3block (B) polydispersity and poly(methyl methacrylate0́3b0́3styrene0́3b0́3methyl methacrylate) triblock copolymers (MSM) with outer0́3block (M) polydispersity reveals that the location of the polydisperse block and how it is connected to the other blocks is critical. Center block polydispersity in SBS, where one block is constrained at two block junctions, leads to a lamellar phase window shift to higher volume fractions of B, increases in domain periodicity, and the stabilization of a new, disordered bicontinuous morphology. The domain periodicity in the MSM triblocks with outer M block polydispersity is at least twice that predicted for monodisperse MSM triblock copolymers. However, in contrast to the SBS triblocks, the polydisperse MSM triblocks exhibit a lamellar phase window shift to lower M block compositions. The behavior of the SBS and MSM triblock copolymers is clarified in the context of the chain architectures present in the melts resulting from the block polydispersity. Preliminary studies of the thin film behavior of the SM diblock and MSM triblock copolymers revealed that despite the polydispersity of the M block, perpendicular microdomain orientation can be achieved. The MSM triblock copolymer thin films exhibit film thickness0́3dependent morphological behavior arising from a confluence of M outer0́3block polydispersity and the presence of a random brush0́3modified substrate. In summation, this dissertation demonstrates that polydispersity can be used to manipulate the phase behavior of block copolymer melts and thin films and may facilitate access to new materials with potentially useful properties.
Download or read book Structures and Dynamics of Block Copolymer Melts and Solutions written by Chang Yeol Ryu and published by . This book was released on 1998 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Block Copolymers written by Ashish Kumar Khandpur and published by . This book was released on 1995 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Investigations of Block Copolymer Melts and Solutions written by Mary Beth Kossuth and published by . This book was released on 1999 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Polydispersity on the Morphology of Polystyrene polyferrocenyldimethylsilane Block Copolymer Thin Films written by Joy Clare Perkinson and published by . This book was released on 2009 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction: As the size of electronic and magnetic devices decreases, nanoscale patterning becomes an increasingly important area of research. Two different approaches have been taken to pattern media: top-down methods such as lithography, and bottom-up methods such as self-assembly. Top-down assembly methods have the advantages of precision and accuracy, but are hard to scale for certain industrial applications due to their low throughput. Self-assembly methods are more easily scalable for applications requiring mass production. Thus, self-assembly has attracted attention and is an area of ongoing research for its potential to create high-throughput, periodic nanoscale patterns. Block copolymers are a class of commonly-studied materials for nanoscale selfassembly. Block copolymers are long molecules that consist of "blocks" of chemically differing polymers attached end-to-end. Under the right conditions, these blocks will phase separate, spontaneously forming periodic microdomains. Diblock copolymers, which have only two blocks, have been found to form a variety of well-ordered morphologies with nanoscale periodicity ...
Download or read book The Equilibrium Theory of Inhomogeneous Polymers written by Glenn Fredrickson and published by Oxford University Press on Demand. This book was released on 2006 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a pedagogical introduction to the theoretical and computer simulation techniques that are useful in the design of polymer formulations including personal care products, multiphase plastic materials, processed foods, and colloidal and nanoparticle dispersions. The book serves to unify previous work in a common language and provides a balanced treatment of analytical theory and numerical techniques, including an introduction to the exciting new field offield-theoretic polymer simulations - the direct numerical simulation of field theory models of meso-structured polymer melts, solutions, and dispersions.
Download or read book Synthesis and Applications of Copolymers written by Anbanandam Parthiban and published by John Wiley & Sons. This book was released on 2014-06-23 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the reactivity of monomers is crucial in creating copolymers and determining the outcome of copolymerization. Covering the fundamental aspects of polymerization, Synthesis and Applications of Copolymers explores the reactivity of monomers and reaction conditions that ensure that the newly formed polymeric materials exhibit desired properties. Referencing a wide-range of disciplines, the book provides researchers, students, and scientists with the preparation of a diverse variety of copolymers and their recent developments, with a particular focus on copolymerization, crystallization, and techniques like nanoimprinting and micropatterning.
Download or read book The Melt Rheology of A b Block Copolymers with Spherical Microdomains written by Ekong A. Ekong and published by . This book was released on 1983 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Block Copolymers written by Kenneth J. Hanley and published by . This book was released on 2001 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Melt Processing and Mechanical Properties of Polyolefin Block Copolymers written by Alhad Phatak and published by . This book was released on 2006 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diffusion in Block Copolymer Melts written by Mark William Hamersky and published by . This book was released on 1997 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase Separation and Morphology of Diblock and Segmented Block Copolymers written by David A. Gobran and published by . This book was released on 1990 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Block Copolymer Phase Behavior written by Chiajen Lai and published by . This book was released on 1999 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlling Morphology of Multi component Block Copolymer Based Materials written by Rafal Adam Mickiewicz and published by . This book was released on 2009 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability of block copolymers to self-assemble into ordered microstructures has attracted much interest both from a pure scientific perspective and for their potential in numerous industrial applications. The microphase separation of block copolymers has been successfully exploited in a wide range of applications, such as templating and lithography, enhancement of mechanical properties, and nano reactor schemes. This thesis focuses on the characterization of the morphology in composite systems where one or more of the components is a block copolymer. In the first part of this thesis, binary blends of very high molecular weight diblock copolymers with a low molecular weight triblock copolymer are investigated. The high molecular weight diblock copolymers are very strongly segregating, with interaction parameter values, XN, in the range 470 - 1410. The phase diagram revealed a large miscibility gap for the blends, with macrophase separation into two distinct types of microphase separated domains and implied virtually no solubility of the much higher molecular weight diblocks in the triblock. For certain blend compositions, morphological transitions from the lamellar to cylindrical and bicontinuous structures were also observed, even though the overall composition in the blend would be expected to favor the lamellar microstructure. This was found to result from the compositional asymmetry of the triblock copolymer influencing the curvature of the inter-material dividing surface (IMDS). Finally, a strong segregation theory model was used to interpret the observed results. In the second part of this thesis the microstructure formation in nanocomposites based on a liquid crystalline side chain block copolymer (LCBCP) and gold nanoparticles was investigated. The location of the nanoparticles was found to not only depend on the surface chemistry of the gold nanoparticles, but also on the self-organization within the liquid crystalline domain of the LCBCP. The nanoparticles were excluded from the liquid crystalline domains due to the high free energy penalty of disrupting the smectic layering. The final location of the nanoparticles within the composite was determined by the nature of the stabilizing surface coating. The work presented in this thesis revealed a number of interesting tools which are useful for obtaining a wide range of morphologies in multi-component block copolymer systems.
Download or read book Dynamics Studies of a Block Copolymer Melt written by Amish Jagdish Patel and published by . This book was released on 2007 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
