Dispersions of ellipsoidal particles in a nematic liquid crystal

TL;DR

This paper investigates how elongated ellipsoidal particles interact within a nematic liquid crystal, revealing new configurations and behaviors influenced by particle shape, boundary conditions, and elastic forces, supported by numerical and experimental analysis.

Contribution

It provides a detailed numerical study of prolate ellipsoids in nematic LCs, uncovering novel topological configurations and orientation behaviors based on aspect ratio and boundary conditions.

Findings

Discovered new topological LC configurations around ellipsoids.

Identified how aspect ratio influences particle orientation.

Showed boundary conditions affect aggregate morphology.

Abstract

Colloidal particles dispersed in a partially ordered medium, such as a liquid crystal (LC) phase, disturb its alignment and are subject to elastic forces. These forces are long-ranged, anisotropic and tunable through temperature or external fields, making them a valuable asset to control colloidal assembly. The latter is very sensitive to the particle geometry since it alters the interactions between the colloids. We here present a detailed numerical analysis of the energetics of elongated objects, namely prolate ellipsoids, immersed in a nematic host. The results, complemented with qualitative experiments, reveal novel LC configurations with peculiar topological properties around the ellipsoids, depending on their aspect ratio and the boundary conditions imposed on the nematic order parameter. The latter also determine the preferred orientation of ellipsoids in the nematic field, because of elastic torques, as well as the morphology of particles aggregates.