Glasses in hard spheres with short-range attraction

TL;DR

This study investigates the structure and dynamics of glassy states in colloidal hard spheres with short-range attraction, revealing re-entrant glass transitions, distinct glass types, and slow dynamics near theoretical predictions.

Contribution

It provides detailed experimental insights into how short-range attraction influences glass formation and transitions in colloidal suspensions, confirming theoretical predictions.

Findings

Observation of re-entrant glass transition.

Identification of two distinct glass types.

Detection of very slow, logarithmic dynamics near the A3 point.

Abstract

We report a detailed experimental study of the structure and dynamics of glassy states in hard spheres with short-range attraction. The system is a suspension of nearly-hard-sphere colloidal particles and non-adsorbing linear polymer which induces a depletion attraction between the particles. Observation of crystallization reveals a re-entrant glass transition. Static light scattering shows a continuous change in the static structure factors upon increasing attraction. Dynamic light scattering results, which cover 11 orders of magnitude in time, are consistent with the existence of two distinct kinds of glasses, those dominated by inter-particle repulsion and caging, and those dominated by attraction. Samples close to the `A3 point' predicted by mode coupling theory for such systems show very slow, logarithmic dynamics.