Author: Chih-Chen HsiehPublisher:
ISBN:
Category :
Languages : en
Pages : 342
Book Description
Brownian Dynamics Simulations of Dilute Polymer Solutions with Complex Hydrodynamics
Author: Chih-Chen HsiehMicrohydrodynamics, Brownian Motion, and Complex Fluids
Author: Michael D. GrahamPublisher: Cambridge University Press
ISBN: 110861440X
Category : Science
Languages : en
Pages : 282
Book Description
This is an introduction to the dynamics of fluids at small scales, the physical and mathematical underpinnings of Brownian motion, and the application of these subjects to the dynamics and flow of complex fluids such as colloidal suspensions and polymer solutions. It brings together continuum mechanics, statistical mechanics, polymer and colloid science, and various branches of applied mathematics, in a self-contained and integrated treatment that provides a foundation for understanding complex fluids, with a strong emphasis on fluid dynamics. Students and researchers will find that this book is extensively cross-referenced to illustrate connections between different aspects of the field. Its focus on fundamental principles and theoretical approaches provides the necessary groundwork for research in the dynamics of flowing complex fluids.
Polymer Dynamics in Dilute Media
Author: Shikha SomaniPublisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 135
Book Description
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 hysteresis using rigorous Brownian dynamics simulations and specifically explore the effect of flow vorticity on the lifetime and width of the hysteresis window in 3-D flows. A systematic procedure is developed with careful eigenvalue analysis to explore the sole effect of vorticity on polymer dynamics keeping the principal strain rate fixed. It is observed that the hysteresis width shrinks due to increase in flow vorticity irrespective of the flow type (bi-extensional, bi-compressional, spiral-inwards, spiral-outwards etc). This is further traced to the alignment of eigenvectors with the principal eigenvector direction leading to enhanced fluctuations. Vorticity is found to have a significant effect on both the transient and the steady state properties. Understanding the effect of vorticity on polymer conformational hysteresis can further help in understanding the fundamental processes in complex flows.
Molecular Dynamics of Dilute Solutions of Polymers and DNA with Applications
Author: Lei LiDynamics Of Complex Fluids: Proceedings Of The Second Royal Society-unilever Indo-uk Forum In Materials Science And Engineering
Author: M J AdamsPublisher: World Scientific
ISBN: 1783263539
Category :
Languages : en
Pages : 513
Book Description
This volume records the presentations and discussions at the Second Royal Society-Unilever Indo-UK Forum on 'Dynamics of Complex Fluids' which was the culmination of the six-month programme on this topic organised at the Issac Newton Institute for Mathematical Sciences, Cambridge University.The authors of this important volume present an up-to-date, wide-ranging view on developments in the analysis of complex fluid behaviour. Emphasis is placed upon the relation between small-scale structure and large-scale response: this brings together the approaches of molecular physics and continuum mechanics.Experiments, constitutive models and computer simulations are combined to yield new insights into the flow behaviour of polymer melts and solutions, colloidal and neutral particle suspensions, and pastes and soils.
Handbook of Materials Modeling
Author: Sidney YipPublisher: Springer Science & Business Media
ISBN: 1402032862
Category : Science
Languages : en
Pages : 2903
Book Description
The first reference of its kind in the rapidly emerging field of computational approachs to materials research, this is a compendium of perspective-providing and topical articles written to inform students and non-specialists of the current status and capabilities of modelling and simulation. From the standpoint of methodology, the development follows a multiscale approach with emphasis on electronic-structure, atomistic, and mesoscale methods, as well as mathematical analysis and rate processes. Basic models are treated across traditional disciplines, not only in the discussion of methods but also in chapters on crystal defects, microstructure, fluids, polymers and soft matter. Written by authors who are actively participating in the current development, this collection of 150 articles has the breadth and depth to be a major contributor toward defining the field of computational materials. In addition, there are 40 commentaries by highly respected researchers, presenting various views that should interest the future generations of the community. Subject Editors: Martin Bazant, MIT; Bruce Boghosian, Tufts University; Richard Catlow, Royal Institution; Long-Qing Chen, Pennsylvania State University; William Curtin, Brown University; Tomas Diaz de la Rubia, Lawrence Livermore National Laboratory; Nicolas Hadjiconstantinou, MIT; Mark F. Horstemeyer, Mississippi State University; Efthimios Kaxiras, Harvard University; L. Mahadevan, Harvard University; Dimitrios Maroudas, University of Massachusetts; Nicola Marzari, MIT; Horia Metiu, University of California Santa Barbara; Gregory C. Rutledge, MIT; David J. Srolovitz, Princeton University; Bernhardt L. Trout, MIT; Dieter Wolf, Argonne National Laboratory.
Polymer and Cell Dynamics
Author: Wolfgang AltPublisher: Birkhäuser
ISBN: 303488043X
Category : Mathematics
Languages : en
Pages : 306
Book Description
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.
Monte Carlo and Molecular Dynamics Simulations in Polymer Science
Author: Kurt BinderPublisher: Oxford University Press, USA
ISBN: 0195094387
Category : Language Arts & Disciplines
Languages : en
Pages : 602
Book Description
Talks about various computer simulation techniques used for macromolecular materials. This book describes how to use simulation to explain experimental data and gain insight into structure and dynamic properties of polymeric structures. Explanations are given on how to overcome challenges posed by large size and slow relaxation polymer coils.
Dissertation Abstracts International
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 902
Book Description
The Mesoscopic Theory of Polymer Dynamics
Author: Vladimir N. PokrovskiiPublisher: Springer Science & Business Media
ISBN: 9048122317
Category : Science
Languages : en
Pages : 256
Book Description
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.