Two-dimensional squishy glass: yielding under oscillatory shear

TL;DR

This study explores how a dense two-dimensional glass of deformable polymer rings responds to oscillatory shear, revealing how ring stiffness influences yielding behavior and shape fluctuations.

Contribution

It introduces a model of two-dimensional deformable polymer rings and investigates how ring stiffness affects yielding and shape changes under shear.

Findings

More flexible rings show broader shape fluctuations.

Yield strain increases as ring stiffness decreases.

Significant shape deviations occur under shear.

Abstract

The yielding response to an imposed oscillatory shear is investigated for a model two-dimensional dense glass composed of bidisperse, deformable polymer rings, with the ring stiffness being the control parameter. In the quiescent glassy state, the more flexible rings exhibit a broader spectrum of shape fluctuations, which becomes increasingly constrained with increasing ring stiffness. Under shear, the highly packed rings yield, i.e. the thermal assembly looses rigidity, with the threshold yield strain increasing significantly with decreasing ring stiffness. Further, the rings display significant deviations in their shape compared to their unsheared counterparts. This study provides insights into the interplay between shape changes and translational rearrangements under shear, thus contributing to the understanding of yielding transition in densely packed, deformable polymer systems.