Phase behavior of colloidal suspensions with critical solvents in terms of effective interactions

TL;DR

This paper investigates how critical Casimir forces influence the phase behavior of colloidal suspensions in binary liquid mixtures near their critical point, using an effective one-component system approach.

Contribution

It introduces an effective approach to study colloidal phase behavior near critical solvents, focusing on critical Casimir forces and phase coexistence.

Findings

Critical Casimir forces induce phase separation in colloidal suspensions.

Effective one-component models can describe colloidal phase behavior near criticality.

The approach's reliability is critically discussed.

Abstract

We study the phase behavior of colloidal suspensions the solvents of which are considered to be binary liquid mixtures undergoing phase segregation. We focus on the thermodynamic region close to the critical point of the accompanying miscibility gap. There, due to the colloidal particles acting as cavities in the critical medium, the spatial confinements of the critical fluctuations of the corresponding order parameter result in the effective, so-called critical Casimir forces between the colloids. Employing an approach in terms of effective, one-component colloidal systems, we explore the possibility of phase coexistence between two phases of colloidal suspensions, one being rich and the other being poor in colloidal particles. The reliability of this effective approach is discussed.