Phase Separation and Self-Assembly in a Fluid of Mickey Mouse Particles

TL;DR

This study explores how the shape and interaction parameters of Mickey Mouse colloidal particles influence their phase separation and self-assembly, revealing conditions that favor gas-liquid coexistence and ordered cluster formation.

Contribution

It provides new insights into how bond length and interaction range control phase behavior and cluster morphology in Mickey Mouse particles.

Findings

Increasing bond length lowers the temperature for phase separation.

Interaction range determines transition between phase separation and cluster self-assembly.

Reduced interaction range and temperature lead to ordered tube-like clusters.

Abstract

Recent developments in the synthesis of colloidal particles allow for control over shape and inter-particle interaction. One example, among others, is the so-called "Mickey Mouse" (MM) particle for which the self-assembly properties have been previously studied yielding a stable cluster phase together with elongated, tube-like structures. Here, we investigate under which conditions a fluid of Mickey Mouse particles can yield phase separation and how the self-assembly behaviour affects the gas-liquid coexistence. We vary the distance between the repulsive and the attractive lobes (bond length), and the interaction range, and follow the evolution of the gas-liquid (GL) coexistence curve. We find that upon increasing the bond length distance the binodal line shifts to lower temperatures, and that the interaction range controls the transition between phase separation and self-assembly of clusters. Upon further reduction of the interaction range and temperature, the clusters assume an increasingly ordered tube-like shape, ultimately matching the one previously reported in literature. These results are of interest when designing particle shape and particle-particle interaction for self-assembly processes.