Reconfigurable swarms of colloidal particles electrophoretically drivenin nematic liquid crystals

TL;DR

This study demonstrates the dynamic assembly and reconfiguration of anisometric colloidal particles in nematic liquid crystals using electrophoresis and photosensitive anchoring, enabling controllable particle trajectories.

Contribution

It introduces a novel method for reconfigurable colloidal swarms in liquid crystals driven by electrophoresis and guided by photo-tunable anchoring conditions.

Findings

Particles can be dynamically assembled and reconfigured.

Particle trajectories follow local director orientation.

Reconfigurable control achieved via photosensitive anchoring layer.

Abstract

We present experiments where anisometric colloidal microparticles dispersed in a nematic liquid crystal cell with homeotropic anchoring conditions are dynamically assembled by means of liquid-crystal-enabled electrophoresis (LCEEP) using an AC electric field perpendicular to the confining plates. A nematic host with negative dielectric anisotropy leads to a driving force parallel to the cell plates. We take advantage of the resulting gliding anchoring conditions and the degeneracy in the direction of particle motion to design reconfigurable trajectories using a photosensitive anchoring layer (azosilane self-assembled monolayer), as the particle trajectory follows the local director orientation.