Nonuniversal routes to universality: Critical phenomena in colloidal dispersions

TL;DR

This paper uses hierarchical reference theory to study critical phenomena in colloids, revealing how tunable interactions lead to diverse crossover behaviors not seen in atomic fluids.

Contribution

It demonstrates how tuning colloidal interactions can produce various crossover routes to critical behavior, expanding understanding beyond atomic fluid universality.

Findings

Tunable interactions cause diverse crossover behaviors.

Hierarchical reference theory effectively models colloidal critical phenomena.

Critical behavior varies significantly with interaction parameters.

Abstract

We investigate critical phenomena in colloids by means of the renormalization-group based hierarchical reference theory of fluids (HRT). We focus on three experimentally relevant model systems: namely, the Asakura-Oosawa model of a colloidal dispersion under the influence of polymer-induced attractive depletion forces; fluids with competing short-range attractive and longer-range repulsive interactions; solutions of star-polymers whose pair potential presents both an attractive well and an ultrasoft repulsion at shorter distance. Our results show that the ability to tune the effective interactions between colloidal particles allows one to generate a variety of crossovers to the asymptotic critical behavior, which are not observed in atomic fluids.