Colloid-Polymer Mixtures Confined Between Asymmetric Walls: Simulation Evidence for an Interface Localization Transition

TL;DR

This study uses grand-canonical Monte Carlo simulations to investigate phase separation in colloid-polymer mixtures confined between asymmetric walls, revealing a transition from capillary condensation to interface localization influenced by wall potentials.

Contribution

It provides simulation evidence for an interface localization transition in colloid-polymer mixtures confined between asymmetric walls, expanding understanding of phase behavior under confinement.

Findings

Identification of a crossover from capillary condensation to interface localization transition.

The transition occurs under conditions of near-complete phase separation in the bulk.

Simulation results highlight the influence of asymmetric wall potentials on phase behavior.

Abstract

Phase separation of colloid-polymer mixtures, described by the Asakura-Oosawa (AO) model, confined in a thin slit pore is studied by grand-canonical Monte Carlo simulation. While one wall is a hard wall for both particles, at the other wall there acts an additional repulsive potential on the colloids only. Varying the strength of this potential, a crossover from capillary condensation to an interface localization transition is found. The latter occurs under conditions where in the bulk almost complete phase separation has occurred.