Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 16: Poster: Dynamics of Molecular Systems, Polymer Dynamics, Glass Transition, Crystallization, Electronic Properties of Polymers

CPP 16.8: Poster

Montag, 2. April 2001, 12:30–15:00, AT1

On the Role of Internal Rotational Barriers in Mesoscale Polymer Melt Dynamics — •Stephan Krushev and Wolfgang Paul — Institut für Physik, Universität Mainz

A molecular dynamics simulation study of the dynamics in a polybutadiene (PBD) melt as determined from a chemically realistic (CRC) and an equivalent freely rotating chain (FRC) model reveals that conformational energetics qualitatively influence chain dynamics on surprisingly large length scales. We compare the normal mode spectrum and the dynamical structure factor of both models to figure out the influence of the torsions on the dynamics. On a mesoscopic scale the mode spectrum of the chemically realistic model is determined by correlations in torsional transitions and exhibits scaling behavior disparate from that found for the FRC model. For the chemically realistic model different temperature dependence is observed for these mesoscopic and smaller scale modes compared to the large length scale motions. This behavior has important implications for the applicability of coarse-grained polymer models and theories of polymer dynamics and suggests a physical picture for the β-process in glassy PBD.