Elastic octopoles and colloidal structures in nematic liquid crystals

TL;DR

This paper introduces a theoretical model explaining how elastic multipole interactions, especially octopoles, lead to the formation of complex colloidal structures in nematic liquid crystals, including effects under external electric fields.

Contribution

It presents a new model emphasizing the role of octopole moments in colloidal structure formation and explains recent experimental observations of electrostriction effects.

Findings

Octopole moments significantly influence colloidal crystal formation.

The model accounts for giant electrostriction in 3D nematic colloids.

Theoretical predictions align with recent experimental results.

Abstract

We propose a simple theoretical model which explains a formation of dipolar 2D and 3D colloidal structures in nematic liquid crystal. Colloidal particles are treated as effective hard spheres interacting via their elastic dipole, quadrupole and octopole moments. It is shown that octopole moment plays an important role in the formation of 2D and 3D nematic colloidal crystals. We generalize this assumption on the case of the external electric field and theoretically explain a giant electrostriction effect in 3D crystals observed recently [A. Nych et al., Nature Communications \textbf{4}, 1489 (2013)].