Berlin 2012 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Poster: Stress Relaxation in Polymers - From single molecules to biological cells (joint focus with BP)
CPP 25.4: Poster
Wednesday, March 28, 2012, 11:00–13:00, Poster A
Computer simulation study of viscoelastic properties of entangled polymers using a translationally invariant slip-spring model — •Veronica Chappa1,2, David Morse3, Annette Zippelius2, and Marcus Müller2 — 1CONICET, Argentina — 2Institut für Theoretische Physik, Georg-August-Universität, Göttingen, Germany — 3Department of Chemical Engineering and Materials Science, University of Minnesota, USA
Different slip-spring models have been proposed and used to describe the behavior of entangled polymers in computer simulation. Some of them break translational invariance by anchoring slip-links to fixed points in space or alter the equilibrium properties of the polymeric chains. We introduce a slip-spring model that represents entanglements via pairwise, translationally and rotationally invariant interactions and exactly compensate for the additional interactions such that the presence of slip-springs does not modify the equilibrium statistics of the polymers. These slip-springs were implemented in computer simulations of a soft coarse-grained polymer model and we study the viscoelastic properties of entangled polymer systems. Each end of a slip-spring can move to a neighboring segment along the chain to which it is attached and renewal processes at chain ends simultaneously account for tube renewal and the effect of constraint release. We present results for the mean squared displacements, shear viscosity, stress relaxation, and diffusion of the slip-springs along the chains in equilibrium and under flow. Our simulation results are compared to theoretical models and experiments.