Phase diagram of hard board like colloids from computer simulations

TL;DR

This study uses Monte Carlo simulations to map the phase diagram of board-like colloids, revealing how shape anisometry influences mesophase structures and phase transitions, including new phase sequences.

Contribution

It provides the first comprehensive phase diagram for sterically interacting board-like colloids across various anisometries, identifying novel phase sequences and geometry requirements.

Findings

Identified various mesophases including uniaxial and biaxial nematics, smectic, cubatic, and columnar phases.

Discovered new phase sequences such as nematic-nematic and direct transitions to smectic A.

Demonstrated the critical influence of molecular shape on phase behavior.

Abstract

The rich mesophase polymorhism and the phase sequence of board-like colloids depends critically on their shape anisometry. Implementing extensive Monte Carlo simulations, we calculated the full phase diagram of sterically interacting board-like particles, for a range of experimentally accessible molecular dimensions/anisometries of colloids of this shape. A variety of self organized mesophases including uniaxial and biaxial nematics, smectic, cubatic and columnar phases have been identified. Our results demonstrate clearly that the molecular anisometry influences critically not only the structure and the symmetry of the mesophases but also, and perhaps more interestingly, the phase sequence among them. New classes of phase sequences such as nematic-nematic and, for the first time, a direct transition from a discotic and a biaxial nematic to an orthogonal smectic A phase have been identified. The molecular geometry requirements for such a phase behavior have been located.