Nontrivial electrophoresis of silica micro and nanorods in a nematic liquid crystal

TL;DR

This paper investigates the complex electrophoretic behavior of silica micro and nanorods in nematic liquid crystals, revealing nonlinear mobility effects and the interplay of elastic and electrostatic torques.

Contribution

It introduces a basic theory for tilting-induced effects and demonstrates a method to measure the rods' effective polarizability in nematic liquid crystals.

Findings

Nonlinear electrophoretic mobility coefficients measured and compared with theory

Elastic and electrostatic torques compete, affecting rod orientation

Method applicable to various asymmetric and polarizable particles

Abstract

We study DC and AC electrophoresis of silica micro and nanorods in a thin film of a nematic liquid crystal. These particles induce virtual topological defects and also demonstrate nontrivial electrophoresis in a nematic liquid crystal. We measure several nonlinear electrophoretic mobility coefficients and compare with those calculated theoretically. We demonstrate a competing effect of the elastic and electrostatic torques that arises due to tilting of the rods with respect to the liquid crystal director. A basic theory describing this effect allows us to measure the effective polarizability of the rods. Our approach is simple and applicable to a wide variety of asymmetric and polarizable particles.