Reentrant phase behaviour for systems with competition between phase separation and self-assembly

TL;DR

This paper investigates reentrant phase behavior in systems where competition between phase separation and self-assembly occurs, using a classical statistical mechanical model to map the phase diagram.

Contribution

It introduces a van der Waals-based model incorporating self-assembly into phase behavior analysis, revealing reentrant phenomena in the phase diagram.

Findings

Reentrant phase behavior observed in the model.

Reentrance occurs within specific density ranges.

Phase separation persists at high densities.

Abstract

In patchy particle systems where there is competition between the self-assembly of finite clusters and liquid-vapour phase separation, reentrant phase behaviour is observed, with the system passing from a monomeric vapour phase to a region of liquid-vapour phase coexistence and then to a vapour phase of clusters as the temperature is decreased at constant density. Here, we present a classical statistical mechanical approach to the determination of the complete phase diagram of such a system. We model the system as a van der Waals fluid, but one where the monomers can assemble into monodisperse clusters that have no attractive interactions with any of the other species. The resulting phase diagrams show a clear region of reentrance. However, for the most physically reasonable parameter values of the model, this behaviour is restricted to a certain range of density, with phase separation still persisting at high densities.