Dynamics and structure of an aging binary colloidal glass

TL;DR

This study investigates the aging process in a binary colloidal glass, revealing how particle size, motion, and structure evolve over time using advanced microscopy techniques.

Contribution

It provides new insights into the microscopic dynamics and structural organization during aging in binary colloidal glasses, emphasizing the role of small particles in facilitating motion.

Findings

Small particles form mobile regions that promote overall particle motion.

Particles move in spatially heterogeneous cooperative groups.

Small particles are enriched in mobile regions, aiding structural relaxation.

Abstract

We study aging in a colloidal suspension consisting of micron-sized particles in a liquid. This system is made glassy by increasing the particle concentration. We observe samples composed of particles of two sizes, with a size ratio of 1:2.1 and a volume fraction ratio 1:6, using fast laser scanning confocal microscopy. This technique yields real-time, three-dimensional movies deep inside the colloidal glass. Specifically, we look at how the size, motion and structural organization of the particles relate to the overall aging of the glass. Particles move in spatially heterogeneous cooperative groups. These mobile regions tend to be richer in small particles, and these small particles facilitate the motion of nearby particles of both sizes.