Particle dynamics in colloidal suspensions above and below the glass-liquid re-entrance transition

TL;DR

This study investigates how colloidal particles transition from a glassy state to a liquid state with attractive interactions, revealing changes in particle dynamics and cooperative motion during the transition.

Contribution

It provides detailed characterization of particle motional events and their evolution across the glass-liquid transition induced by short-range depletion forces.

Findings

Particle speed during motional events increases by about tenfold in the attractive liquid.

Particles move more cooperatively in the attractive liquid phase.

Displacements of particles in the attractive liquid are not significantly larger than in the glass.

Abstract

We study colloidal particle dynamics of a model glass system using confocal and fluorescence microscopy as the sample evolves from a hard-sphere glass to a liquid with attractive interparticle interactions. The transition from hard-sphere glass to attractive liquid is induced by short-range depletion forces. The development of liquid-like structure is indicated by particle dynamics. We identify particles which exhibit substantial motional events and characterize the transition using the properties of these motional events. As samples enter the attractive liquid region, particle speed during these motional events increases by about one order of magnitude, and the particles move more cooperatively. Interestingly, colloidal particles in the attractive liquid phase do not exhibit significantly larger displacements than particles in the hard-sphere glass.