Nonergodicity transitions in colloidal suspensions with attractive interactions

TL;DR

This paper uses mode coupling theory to analyze nonergodicity transitions in colloidal suspensions with short-range attractive interactions, linking gel and glass transitions and comparing theoretical predictions with experimental observations.

Contribution

It demonstrates how mode coupling theory predicts nonergodic states and the influence of attraction range on the phase diagram in colloidal systems.

Findings

Weak attraction increases the critical glass transition concentration.

Low temperature nonergodic states extend into the subcritical region.

Features of the transition align qualitatively with experimental gel transition data.

Abstract

The colloidal gel and glass transitions are investigated using the idealized mode coupling theory (MCT) for model systems characterized by short-range attractive interactions. Results are presented for the adhesive hard sphere and hard core attractive Yukawa systems. According to MCT, the former system shows a critical glass transition concentration that increases significantly with introduction of a weak attraction. For the latter attractive Yukawa system, MCT predicts low temperature nonergodic states that extend to the critical and subcritical region. Several features of the MCT nonergodicity transition in this system agree qualitatively with experimental observations on the colloidal gel transition, suggesting that the gel transition is caused by a low temperature extension of the glass transition. The range of the attraction is shown to govern the way the glass transition line traverses the phase diagram relative to the critical point, analogous to findings for the fluid-solid freezing transition.