Effect of ring stiffness and ambient pressure on the dynamical slowdown in ring polymers

TL;DR

This study uses molecular dynamics simulations to explore how ring stiffness and ambient pressure influence the dynamical slowdown and glass formation in ring polymers, highlighting the role of topological threading.

Contribution

It reveals that ring stiffness and threading are key factors in the dynamical slowdown and glassiness of ring polymers, providing a new framework for understanding topologically constrained polymer glasses.

Findings

Stiffer rings lead to glassiness at lower pressures.

Threading is a crucial factor in dynamical slowdown.

A phase space framework for polymer glasses is proposed.

Abstract

Using extensive molecular dynamics simulations, we investigate the slowing down of dynamics in a 3D system of ring polymers by varying the ambient pressure and the stiffness of the rings. Our study demonstrates that the stiffness of the rings determines the dynamics of the ring polymers, leading to glassiness at lower pressures for stiffer rings. The threading of the ring polymers, a unique feature that emerges only due to the topological nature of such polymers in three dimensions, is shown to be the determinant feature of dynamical slowing down, albeit only in a certain stiffness range. Our results suggest a possible framework of exploring the phase space spanned by ring stiffness and pressure to obtain spontaneously emerging topologically constrained polymer glasses.