Tests of mode coupling theory in a simple model for two-component miscible polymer blends

TL;DR

This study uses molecular dynamics simulations to test Mode Coupling Theory predictions in a simple polymer blend model, revealing a large exponent parameter indicating potential higher-order dynamic arrest scenarios.

Contribution

It provides the first detailed simulation analysis of MCT in a two-component polymer blend with size disparity, highlighting a large exponent parameter and suggesting complex arrest mechanisms.

Findings

Large time scale separation observed between components

Unusually large MCT exponent parameter found

Evidence suggests higher-order dynamic arrest scenario

Abstract

We present molecular dynamics simulations on the structural relaxation of a simple bead-spring model for polymer blends. The introduction of a different monomer size induces a large time scale separation for the dynamics of the two components. Simulation results for a large set of observables probing density correlations, Rouse modes, and orientations of bond and chain end-to-end vectors, are analyzed within the framework of the Mode Coupling Theory (MCT). An unusually large value of the exponent parameter is obtained. This feature suggests the possibility of an underlying higher-order MCT scenario for dynamic arrest.