Partial rejuvenation of a colloidal glass

TL;DR

This paper investigates how shear influences the aging process of a colloidal glass, revealing a simple exponential reduction in relaxation time proportional to shear amplitude, which supports an Eyring-like dynamic model.

Contribution

It introduces a quantitative law describing shear-induced rejuvenation in colloidal glasses, linking shear amplitude to relaxation time reduction.

Findings

Shear reduces relaxation time exponentially with shear amplitude.

Rejuvenation effect is independent of shear duration and frequency.

Supports an Eyring-like model for colloidal dynamics.

Abstract

We study the effect of shear on the aging dynamics of a colloidal suspension of synthetic clay particles. We find that a shear of amplitude $\gamma$ reduces the relaxation time measured just after the cessation of shear by a factor $\exp(-\gamma/\gamma_c)$, with $\gamma_c \sim 5%$, and is independent of the duration and the frequency of the shear. This simple law for the rejuvenation effect shows that the energy involved in colloidal rearrangements is proportional to the shear amplitude, $\gamma$, rather than $\gamma^2$, leading to an Eyring-like description of the dynamics of our system.