Gel and glass transition in fragile colloidal clays

TL;DR

This study investigates the aging dynamics and transition behaviors of Laponite colloidal suspensions using DLS, drawing analogies with supercooled liquids and analyzing fragility across various conditions.

Contribution

It provides new insights into the gel and glass transition phenomena in fragile colloidal clays through comprehensive experimental analysis and fragility characterization.

Findings

Aging slows down dynamics near gel and glass transitions.

Fragility varies with concentration, solvent, salt, and polymer addition.

An Angell plot illustrates the structural relaxation times.

Abstract

Dynamic Light Scattering (DLS) measurements were performed on colloidal suspensions of Laponite\textsuperscript{\textregistered} at different concentrations in the range $C_\text{w}= (1.5{\div}3.0)$%. The slowing down of the dynamics induced by aging was monitored by following the temporal evolution of autocorrelation functions at different concentrations towards the gel and glass transition. Exploiting analogies with supercooled liquids approaching their glass transitions, an Angell plot for the structural relaxation times was drawn. Finally, the fragility of Laponite\textsuperscript{\textregistered} suspensions at different concentrations, in different solvents, at two salt concentrations and with the addition of a polymer was reported and discussed.