<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Iyer, Balaji V. S.</style></author><author><style face="normal" font="default" size="100%">Lele, Ashish K.</style></author><author><style face="normal" font="default" size="100%">Juvekar, Vinay A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Flexible ring polymers in an obstacle environment: Molecular theory of linear viscoelasticity</style></title><secondary-title><style face="normal" font="default" size="100%">Physical Review E</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">AUG</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">2, 1</style></number><publisher><style face="normal" font="default" size="100%">AMERICAN PHYSICAL SOC</style></publisher><pub-location><style face="normal" font="default" size="100%">ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA</style></pub-location><volume><style face="normal" font="default" size="100%">74</style></volume><pages><style face="normal" font="default" size="100%">Article No. 021805</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;We formulate a coarse-grained mean-field approach to study the dynamics of the flexible ring polymer in any given obstacle (gel or melt) environment. The similarity of the static structure of the ring polymer with that of the ideal randomly branched polymer is exploited in formulating the dynamical model using aspects of the pom-pom model for branched polymers. The topological constraints are handled via the tube model framework. Based on our formulation we obtain expressions for diffusion coefficient D, relaxation times tau, and dynamic structure factor g(k,t). Further, based on the framework we develop a molecular theory of linear viscoelasticity for ring polymers in a given obstacle environment and derive the expression for the relaxation modulus G(t). The predictions of the theoretical model are in agreement with previously proposed scaling arguments and in qualitative agreement with the available experimental results for the melt of rings.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><work-type><style face="normal" font="default" size="100%">Article</style></work-type><custom3><style face="normal" font="default" size="100%">&lt;p&gt;Foreign&lt;/p&gt;</style></custom3><custom4><style face="normal" font="default" size="100%">2.252</style></custom4></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>10</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lele, Ashish K.</style></author><author><style face="normal" font="default" size="100%">Iyer, Balaji V. S.</style></author><author><style face="normal" font="default" size="100%">Juvekar, Vinay A.</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Co, A.</style></author><author><style face="normal" font="default" size="100%">Leal, L. G.</style></author><author><style face="normal" font="default" size="100%">Colby, R. H.</style></author><author><style face="normal" font="default" size="100%">Giacomin, A. J.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Blob-spring model for the dynamics of ring polymer in obstacle environment</style></title><secondary-title><style face="normal" font="default" size="100%">XVTH International Congress on Rheology - the Society of Rheology 80th Annual Meeting, Pts 1 and 2</style></secondary-title><tertiary-title><style face="normal" font="default" size="100%">AIP CONFERENCE PROCEEDINGS</style></tertiary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">fractal polymer dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">linear viscoelasticity</style></keyword><keyword><style  face="normal" font="default" size="100%">ring polymer dynamics</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">AUG</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">Soc Rheol</style></publisher><pub-location><style face="normal" font="default" size="100%">2 Huntington Quadrangle, STE 1no1, Melville, NY 11747-4501 USA</style></pub-location><volume><style face="normal" font="default" size="100%">1027</style></volume><pages><style face="normal" font="default" size="100%">445-447</style></pages><isbn><style face="normal" font="default" size="100%">978-0-7354-0549-3</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The dynamical behavior of cyclic macromolecules in a fixed obstacle (FO) environment is very different than the behavior of linear chains in the same topological environment; while the latter relax by a snake-like reptational motion from their chain ends(1) the former can relax only by contour length fluctuations since they are endless.(2) Duke, Obukhov and Rubinstein proposed a scaling model (the DOR model) to interpret the dynamical scaling exponents shown by Monte Carlo simulations of rings in a FO environment.(2) We present a model (blob-spring model) to describe the dynamics of flexible and non-concatenated ring polymer in FO environment based on a theoretical formulation developed for the dynamics of an unentangled fractal polymer.(3) We argue that the perpetual evolution of ring perimeter by the motion of contour segments results in an extra frictional load. Our model predicts self-similar dynamics with scaling exponents for the molecular weight dependence of diffusion coefficient and relaxation times that are in agreement with the scaling model proposed by Obukhov et al.(2).&lt;/p&gt;</style></abstract><notes><style face="normal" font="default" size="100%">15th International Congress on Rheology/80th Annual Meeting of the Society-of-Rheology, Monterey, CA, AUG 03-08, 2008</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Iyer, Balaji V. S.</style></author><author><style face="normal" font="default" size="100%">Lele, Ashish K.</style></author><author><style face="normal" font="default" size="100%">Juvekar, Vinay A.</style></author><author><style face="normal" font="default" size="100%">Mashelkar, Raghunath Anant</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Self-similar dynamics of a flexible ring polymer in a fixed obstacle environment: a coarse-grained molecular model</style></title><secondary-title><style face="normal" font="default" size="100%">Industrial &amp; Engineering Chemistry Research</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">NOV</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">21</style></number><publisher><style face="normal" font="default" size="100%">AMER CHEMICAL SOC</style></publisher><pub-location><style face="normal" font="default" size="100%">1155 16TH ST, NW, WASHINGTON, DC 20036 USA</style></pub-location><volume><style face="normal" font="default" size="100%">48</style></volume><pages><style face="normal" font="default" size="100%">9514-9522</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In this contribution we concern ourselves with an interesting problem, namely, the dynamics of ideal flexible ring polymers constrained in tin array of fixed obstacles. The fundamental issue in this problem is to understand how a topologically constrained polymer chain is able to relax its conformation in the absence of chain ends. The key physics was provided in tin elegant scaling theory by Rubinstein and co-workers (Obukhov, S. P; Rubinstein, M.; Duke, T. Dynamics of a Ring Polymer in a Gel. Phys. Rev. Lett. 1994, 73, 1263-1267). In this work we develop a coarse-grained mean-field model based oil the physical arguments of the scaling theory and derive constitutive relations for rings in fixed obstacle and melt environments. The model is composed of three distinct steps. In the first step the dynamics of an arbitrary section of a ring chain is worked out based oil fractal Blob-Spring (BS) dynamics, and the center of mass diffusion and the relaxation spectrum of this section are determined. In the second step the center of mass diffusion obtained using the BS dynamics is used to model the one-dimensional diffusion of the section in a topologically constrained environment. In the final step we invoke the idea of dynamic self-similarity and argue that the dynamics described in the first and the second step, for any arbitrary section of the chain, applies to all sections of the chain. The constitutive relation is obtained consequently as the superposition of dynamic response of all sections of the ring chain.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">21</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">2.071</style></custom4></record></records></xml>