Behavior of colloidal particles at an air/nematic liquid crystal interface

TL;DR

This study investigates how spherical silica particles behave at an air-nematic liquid crystal interface, revealing structure formation driven by elastic and capillary interactions, with insights into the effects of gravity and interface curvature.

Contribution

It provides a detailed analysis of particle interactions and pattern formation at the interface, combining experimental observations with theoretical explanations.

Findings

Particles form various structures depending on density and nematic thickness

Pair potential determined using optical tweezers explains pattern formation

Gravity influences particle arrangements on curved interfaces

Abstract

We examine the behavior of spherical silica particles trapped at an air-nematic liquid crystal interface. When a strong normal anchoring is imposed, the beads spontaneously form various structures depending on their area density and the nematic thickness. Using optical tweezers, we determine the pair potential and explain the formation of these patterns. The energy profile is discussed in terms of capillary and elastic interactions. Finally, we detail the mechanisms that control the formation of an hexagonal lattice and analyze the role of gravity for curved interfaces.