Defect-polymorphism controlled electrophoretic propulsion of anisometric microparticles in a nematic liquid crystal

TL;DR

This study investigates how the shape-induced defect structures in anisometric particles influence their electrophoretic movement in nematic liquid crystals, revealing new control mechanisms for microfluidic applications.

Contribution

It demonstrates that particle shape asymmetry causes defect-polymorphism, which in turn controls the direction and speed of electrophoretic propulsion in liquid crystals.

Findings

Shape asymmetry induces defect-polymorphism in particles.

Defect types influence propulsion direction and magnitude.

Results suggest new microfluidic manipulation strategies.

Abstract

Nontrivial shape of colloidal particles create complex elastic distortions and topological defects in liquid crystals and play a key role in governing their electrophoretic propulsion through the medium. Here, we report experimental results on defects and electrophoretic transport of anisometric (snowman-shaped) dielectric particles subjected to an alternating electric field perpendicular to the director in a nematic liquid crystal. We demonstrate that the shape asymmetry gives rise to defect-polymorphism by nucleating point or ring defects at multiple locations on the particle and controls the direction as well as the magnitude of the electrophoretic propulsion. Our findings unveil a novel degree of freedom in translocating microparticles in liquid crystals for applications in microfluidics, controlled transport and assembly.