3A15 Direct Observation of Anisotropic Inter-particle Interactions in Nematic Liquid Crystals

Abstract

Colloidal dispersion systems in nematic media introduce several types of topological defects around a dispersed particle, such as a hyperbolic hedgehog, boojums, and a Saturn ring. These defects are induced by the anchoring effect of the particle surface, and provide anisotropic inter-particle interactions. The anisotropic interactions between solid particles having hyperbolic hedgehog defects have been investigated by using a laser trapping method, which allows us to directly measure inter-particle forces of a pico-newton order in various configurations. We created the two-dimensional force map around a particle, and compared that with a theoretical prediction for the dipolar attractive interaction.