Correlations of Structure and Dynamics in an Aging Colloidal Glass

TL;DR

This study investigates how the static structure of aging colloidal glasses relates to their slowing dynamics, finding weak correlations between local tetrahedral structures and particle mobility.

Contribution

It introduces a detailed analysis linking static tetrahedral structures to dynamic aging behavior in colloidal glasses, revealing subtle structural influences on particle mobility.

Findings

Sample aging correlates with slowed particle motion.

Static tetrahedral structures do not significantly change during aging.

Weak correlation exists between tetrahedron shape and particle mobility.

Abstract

We study concentrated colloidal suspensions, a model system which has a glass transition. Samples in the glassy state show aging, in that the motion of the colloidal particles slows as the sample ages from an initial state. We study the relationship between the static structure and the slowing dynamics, using confocal microscopy to follow the three-dimensional motion of the particles. The structure is quantified by considering tetrahedra formed by quadruplets of neighboring particles. We find that while the sample clearly slows down during aging, the static properties as measured by tetrahedral quantities do not vary. However, a weak correlation between tetrahedron shape and mobility is observed, suggesting that the structure facilitates the motion responsible for the sample aging.