Polymer Dynamics and Relaxation

Author: Richard Boyd
Publisher: Cambridge University Press
ISBN: 1107320259
Format: PDF, Docs
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Polymers exhibit a range of physical characteristics, from rubber-like elasticity to the glassy state. These particular properties are controlled at the molecular level by the mobility of the structural constituents. Remarkable changes in mobility can be witnessed with temperature, over narrow, well defined regions, termed relaxation processes. This is an important, unique phenomenon controlling polymer transition behaviour and is described here at an introductory level. The important types of relaxation processes from amorphous to crystalline polymers and polymeric miscible blends are covered, in conjunction with the broad spectrum of experimental methods used to study them. In-depth discussion of molecular level interpretation, including atomistic level computer simulations and applications to molecular mechanism elucidation, are discussed. The result is a self-contained approach to polymeric interpretation suitable for researchers in materials science, physics and chemistry interested in the relaxation processes of polymeric systems.

The Mesoscopic Theory of Polymer Dynamics

Author: Vladimir N. Pokrovskii
Publisher: Springer Science & Business Media
ISBN: 9789048122318
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The theory presented in this book explains in a consistent manner all dynamics effects observed in very concentrated solutions and melts of linear polymers from a macromolecular point of view. The presentation is compact and self-contained.

Phenomenology of Polymer Solution Dynamics

Author: George D. J. Phillies
Publisher: Cambridge University Press
ISBN: 1139504517
Format: PDF, ePub, Docs
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Presenting a completely new approach to examining how polymers move in non-dilute solution, this book focuses on experimental facts, not theoretical speculations, and concentrates on polymer solutions, not dilute solutions or polymer melts. From centrifugation and solvent dynamics to viscosity and diffusion, experimental measurements and their quantitative representations are the core of the discussion. The book reveals several experiments never before recognized as revealing polymer solution properties. A novel approach to relaxation phenomena accurately describes viscoelasticity and dielectric relaxation and how they depend on polymer size and concentration. Ideal for graduate students and researchers interested in the properties of polymer solutions, the book covers real measurements on practical systems, including the very latest results. Every significant experimental method is presented in considerable detail, giving unprecedented coverage of polymers in solution.

The Theory of Polymer Dynamics

Author: Masao Doi
Publisher: Oxford University Press
ISBN: 9780198520337
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'This book is destined to join the classics of polymer science...an essential purchase for any serious student of polymer dynamics.' British Polymer Journal

Polymer Dynamics in Dilute Media

Author:
Publisher: Stanford University
ISBN:
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Polymers undergo a sharp coil to stretch conformational transition in extension dominated flows when the strain rate exceeds a critical value. Dramatic change in flow behavior is known to occur at the coil-stretch transition, making it useful for several commercial applications. Despite decades of study, this phenomenon remains surrounded with controversy as the effect of solvent properties and fluid flow elements on this transition is not fully understood. In this work, we present a study of the coil-stretch transition and related hysteresis phenomenon using stochastic computer simulations. We first investigate the effect of solvent quality on the coil-stretch transition using Brownian dynamics simulations. Unlike experiments, which are plagued with problems related to polydispersity of polymers and inaccurate control over flow profiles, simulations offer a powerful platform to systematically study the effect of solvent quality while keeping all other parameters in the system constant. The system consists of a polymer subjected to planar elongational flow in both theta solvents and good solvents. The polymer is represented by a bead-spring chain model undergoing elongational flow. Solvent-mediated effects such as fluctuating hydrodynamic interactions (HI) and excluded volume (EV) are included rigorously. Conformational hysteresis is understood in terms of a 1-D energy landscape theory with an activation energy barrier for transition. At steady state, depending upon the flow rate, the energy landscape can either have one or two energy wells. An energy landscape with one well corresponds to the coiled state at low flow rate and stretched state at high flowrate. The double welled landscape corresponds to the hysteretic regime where both coiled and stretched conformational states coexist across the ensemble population. A key factor in determining the effect of solvent quality is the use of a proper measure of solvent quality. In almost all earlier studies, the effect of molecular weight on solvent quality has been neglected, producing inconsistent results. Here, the solvent quality is quantified carefully such that the effect of molecular weight and temperature is taken into account. Contrary to earlier findings, it is observed that with improvement in solvent quality, the chains unravel faster and the critical strain rate at which the coil to stretch transition takes place decreases. Furthermore, the solvent quality has a profound effect on the scaling of the critical strain rate with molecular weight and on both the transient and steady state properties of the system. Universal functions are shown to exist for the observed dynamic and static properties, which will prove useful in determining the operating parameters for experiments. In particular, the ratio of the two different relaxation times (longest relaxation time and zero shear rate viscosity) is found to be a universal function of solvent quality independent of molecular weight. The relaxation times (both the longest relaxation time and the zero shear rate viscosity) increase while the critical strain rate is found to decrease with solvent quality. Next, the study of conformational hysteresis is extended to more complicated 3-D flows to understand the effect of flow vorticity on this phenomenon. Heretofore, there has been no systematic methodology for studying the dynamical interactions between polymer molecules and elementary flow patterns in three-dimensional flows. Such a framework is essential not just for gaining valuable insights into the physics of complex fluids at a fundamental level, but it is also crucial for various important applications like turbulent drag reduction where the underlying physical mechanisms involve dynamical interactions between polymers and turbulence fine scale flow features. Such a study is presented here to provide a framework to interpret complex fluid phenomenon in terms of elementary flow patterns. We investigate the conformational

Polymer and Cell Dynamics

Author: Wolfgang Alt
Publisher: Springer Science & Business Media
ISBN: 9783764369248
Format: PDF, Kindle
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Polymer and cell dynamics play an important role in processes like tumor growth, metastasis, embryogenesis, immune reactions and regeneration. Based on an international workshop on numerical simulations of polymer and cell dynamics in Bad Honnef (Germany) in 2000, this volume provides an overview of the relevant mathematical and numerical methods, their applications and limits. Polymer and Cell Dynamics will be of interest to scientists and advanced undergraduates.

Principles of Soft Matter Dynamics

Author: Rainer Kimmich
Publisher: Springer Science & Business Media
ISBN: 9400755368
Format: PDF
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Practical applications of soft-matter dynamics are of vital importance in material science, chemical engineering, biophysics and biotechnology, food processing, plastic industry, micro- and nano-system technology, and other technologies based on non-crystalline and non-glassy materials. Principles of Soft-Matter Dynamics. Basic Theories, Non-invasive Methods, Mesoscopic Aspects covers fundamental dynamic phenomena such as diffusion, relaxation, fluid dynamics, normal modes, order fluctuations, adsorption and wetting processes. It also elucidates the applications of the principles and of the methods referring to polymers, liquid crystals and other mesophases, membranes, amphiphilic systems, networks, and porous media including multiphase and multi-component materials, colloids, fine-particles, and emulsions. The book presents all formalisms, examines the basic concepts needed for applications of soft-matter science, and reviews non-invasive experimental techniques such as the multi-faceted realm of NMR methods, neutron and light quasi-elastic scattering, mechanical relaxation and dielectric broadband spectroscopy which are treated and compared on a common and consistent foundation. The standard concepts of dynamics in fluids, polymers, liquid crystals, colloids and adsorbates are comprehensively derived in a step-by-step manner. Principles and analogies common to diverse application fields are elucidated and theoretical and experimental aspects are supplemented by computational-physics considerations. Principles of Soft-Matter Dynamics. Basic Theories, Non-invasive Methods, Mesoscopic Aspects appeals to graduate and PhD students, post-docs, researchers, and industrial scientists alike.

Characterization of Polymer Blends

Author: Sabu Thomas
Publisher: John Wiley & Sons
ISBN: 3527645616
Format: PDF, Docs
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Filling the gap for a reference dedicated to the characterization of polymer blends and their micro and nano morphologies, this book provides comprehensive, systematic coverage in a one-stop, two-volume resource for all those working in the field. Leading researchers from industry and academia, as well as from government and private research institutions around the world summarize recent technical advances in chapters devoted to their individual contributions. In so doing, they examine a wide range of modern characterization techniques, from microscopy and spectroscopy to diffraction, thermal analysis, rheology, mechanical measurements and chromatography. These methods are compared with each other to assist in determining the best solution for both fundamental and applied problems, paying attention to the characterization of nanoscale miscibility and interfaces, both in blends involving copolymers and in immiscible blends. The thermodynamics, miscibility, phase separation, morphology and interfaces in polymer blends are also discussed in light of new insights involving the nanoscopic scale. Finally, the authors detail the processing-morphology-property relationships of polymer blends, as well as the influence of processing on the generation of micro and nano morphologies, and the dependence of these morphologies on the properties of blends. Hot topics such as compatibilization through nanoparticles, miscibility of new biopolymers and nanoscale investigations of interfaces in blends are also addressed. With its application-oriented approach, handpicked selection of topics and expert contributors, this is an outstanding survey for anyone involved in the field of polymer blends for advanced technologies.