Entropic self-assembly of freely rotating polyhedral particles confined to a flat interface

TL;DR

This study uses Monte Carlo simulations to explore how freely rotating polyhedral particles confined to a flat interface self-assemble, revealing shape-dependent phase behaviors and similarities with bulk and 2D systems, advancing understanding of interfacial self-assembly.

Contribution

It introduces a detailed simulation analysis of entropic self-assembly of polyhedral particles at interfaces, highlighting shape effects and phase similarities with other systems.

Findings

Shapes with small s behave square-like.

Shapes with large s tend to be disc-like.

Intermediate s shows mixed phase features.

Abstract

The self-assembly of hard polyhedral particles confined to a flat interface is studied using Monte Carlo simulations. The particles are pinned to the interface by restricting their movement in the direction perpendicular to it while allowing their free rotations. The six different polyhedral shapes studied in this work are selected from a family of truncated cubes defined by a truncation parameter, s, which varies from cubes (s = 0) via cuboctahedra (s = 0.5) to octahedra (s = 1). Our results suggest that shapes with small values of s show square-like behavior whereas shapes with large values of s tend to show more disc-like behavior. At an intermediate value of s = 0.4, the phase behavior of the system shows both square-like and disc-like features. The results are also compared with the phase behavior of 3D bulk polyhedra and of 2D rounded hard squares. Both comparisons reveal key similarities in the number and sequence of mesophases and solid phases observed. These insights on 2D entropic self-assembly of polyhedral particles is a first step toward understanding the self-assembly of particles at fluid-fluid interfaces, which is driven by a complex interplay of entropic and enthalpic forces.