Aging near rough and smooth boundaries in colloidal glasses

TL;DR

This study investigates how boundary roughness affects aging in colloidal glasses, revealing that smooth boundaries induce layering and slow dynamics, while rough boundaries suppress layering and maintain bulk-like behavior.

Contribution

It demonstrates that boundary roughness significantly influences aging and structural layering in colloidal glasses, a novel insight into boundary effects on glassy dynamics.

Findings

Smooth boundaries cause layering and slow particle motion.

Rough boundaries suppress layering and preserve bulk dynamics.

Boundary-induced structural gradients affect aging behavior.

Abstract

We use confocal microscopy to study the aging of a bidisperse colloidal glass near rough and smooth boundaries. Near smooth boundaries, the particles form layers, and particle motion is dramatically slower near the boundary as compared to the bulk. Near rough boundaries, the layers nearly vanish, and particle motion is nearly identical to that of the bulk. The gradient in dynamics near the boundaries is demonstrated to be a function of the gradient in structure for both types of boundaries.Our observations show that wall-induced layer structures strongly influence aging.