Reentrant glass transition in a colloid-polymer mixture with depletion attractions

TL;DR

This study demonstrates that adding short-range attractions to colloidal suspensions induces a reentrant glass transition, where the system first melts then re-freezes into a gel-like state, aligning with recent theories.

Contribution

It provides experimental evidence of reentrant glass transitions in colloid-polymer mixtures, confirming theoretical predictions about complex phase behavior.

Findings

Attraction-induced melting of colloidal glass

Formation of gel-like nonergodic states at higher attraction strengths

Reentrant glass transition observed experimentally

Abstract

Performing light scattering experiments we show that introducing short-ranged attraction to a colloidal suspension of nearly hard spheres by addition of free polymer produces new glass transition phenomena. We observe a dramatic acceleration of the density fluctuations amounting to the melting of a colloidal glass. Increasing the strength of the attractions the system freezes into another nonergodic state sharing some qualitative features with gel states occurring at lower colloid packing fractions. This reentrant glass transition is in qualitative agreement with recent theoretical predictions.