Dynamic Arrest in Polymer Melts: Competition between Packing and Intramolecular Barriers

Abstract

We present molecular dynamics simulations of a simple model for polymer melts with intramolecular barriers. We investigate structural relaxation as a function of the barrier strength. Dynamic correlators can be consistently analyzed within the framework of the Mode Coupling Theory (MCT) of the glass transition. Control parameters are tuned in order to induce a competition between general packing effects and polymer-specific intramolecular barriers as mechanisms for dynamic arrest. This competition yields unusually large values of the so-called MCT exponent parameter and rationalize qualitatively different observations for simple bead-spring and realistic polymers. The systematic study of the effect of intramolecular barriers presented here also establishes a fundamental difference between the nature of the glass transition in polymers and in simple glass-formers.

4 pages, 3 figures, 2 tables

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• Fragility and elasticity - a new perspective
• A fast transferable method for predicting the glass transition temperature of polymers from chemical structure
• Glass formation in mechanically interlocked ring polymers: the role of induced chain stiffness
• Static and dynamic contributions to anomalous chain dynamics in polymer blends