Johari-Goldstein heterogeneous dynamics in a model polymer

TL;DR

This study uses molecular dynamics simulations to reveal the heterogeneous nature of Johari-Goldstein relaxation in a model polymer, showing a double-peaked dynamic heterogeneity linked to different relaxation times.

Contribution

It provides mechanistic insights into the double-peaked dynamic heterogeneity of JG relaxation in polymers, highlighting the weak correlation between short- and long-time displacements.

Findings

Double-peaked dynamic heterogeneity observed at JG and structural relaxation times

Weak correlation between short-time and long-time particle displacements during relaxation

Mechanistic explanation for the heterogeneity in polymer dynamics

Abstract

The heterogeneous character of the Johari-Goldstein (JG) relaxation is evidenced by molecular-dynamics simulation of a model polymer system. A double-peaked evolution of dynamic heterogeneity (DH), with maxima located at JG and structural relaxation time scales, is observed and mechanistically explained. {The short-time single-particle displacement during JG relaxation weakly correlates with the long-time one observed during structural relaxation}.