Tunable colloid trajectories in nematic liquid crystals near wavy walls

TL;DR

This paper presents a method to control colloid movement in nematic liquid crystals by designing energy landscapes with wavy walls, enabling precise manipulation of particle trajectories for applications in reconfigurable systems and microrobotics.

Contribution

It introduces a novel approach to steer colloids using elastic energy landscapes created by wavy walls in nematic liquid crystals, allowing for stable and unstable loci to guide particles.

Findings

Colloids can be directed along predefined paths using energy gradients.

Stable and unstable trapping sites are created by the wavy wall design.

The system enables targeted delivery of particles within the domain.

Abstract

The ability to dictate colloid motion is an important challenge in fields ranging from materials science to living systems. Here, by embedding energy landscapes in confined nematic liquid crystals, we design a versatile platform to define colloidal migration. This is achieved by placing a wavy wall, with alternating hills and wells, in nematic liquid crystals, to impose a smooth elastic energy field with alternating splay and bend distortions. This domain generates (meta) stable loci that act as attractors and unstable loci that repel colloids over distances large compared to the colloid radius. Energy gradients in the vicinity of these loci are exploited to dictate colloid trajectories. We demonstrate several aspects of this control, by studying transitions between defect configurations, propelling particles along well defined paths and exploiting multistable systems to send particles to particular sites within the domain. Such tailored landscapes have promise in reconfigurable systems and in microrobotics applications