Structural and conformational dynamics of supercooled polymer melts: Insights from first-principles theory and simulations

TL;DR

This study combines first-principles theory and simulations to analyze the structural and conformational dynamics of supercooled polymer melts, revealing insights into glassy arrest and chain behavior.

Contribution

It provides a quantitative comparison between mode-coupling theory and simulations, highlighting the role of monomer-caging and chain connectivity in slow relaxation.

Findings

Semiquantitative agreement between theory and simulation.

Onset of slow relaxation explained by monomer-caging and chain connectivity.

Unified description of glassy arrest and conformational fluctuations.

Abstract

We report on quantitative comparisons between simulation results of a bead-spring model and mode-coupling theory calculations for the structural and conformational dynamics of a supercooled, unentangled polymer melt. We find semiquantitative agreement between simulation and theory, except for processes that occur on intermediate length scales between the compressibility plateau and the amorphous halo of the static structure factor. Our results suggest that the onset of slow relaxation in a glass-forming melt can be described in terms of monomer-caging supplemented by chain connectivity. Furthermore, a unified atomistic description of glassy arrest and of conformational fluctuations that (asymptotically) follow the Rouse model, emerges from our theory.