Inelastic collisions and anisotropic aggregation of particles in a nematic collider driven by backflow

TL;DR

This paper presents a nematic collider system that uses electric field-driven backflow in liquid crystals to control anisotropic aggregation of colloidal particles through inelastic, dipolar interactions.

Contribution

It introduces a novel nematic collider setup that enables controlled, out-of-equilibrium anisotropic aggregation of colloids via electric field-induced backflow and dipolar interactions.

Findings

Head-to-tail collisions lead to longitudinal aggregates.

Head-to-head collisions promote transversal aggregation.

Impact parameter controls aggregate shape and anisotropy.

Abstract

We design a nematic collider for controlled out-of-equilibrium anisotropic aggregation of spherical colloidal particles. The nematic surrounding imparts dipolar interactions among the spheres. A bidirectional backflow of the nematic liquid crystal (NLC) in a periodic electric field forces the spheres to collide with each other. The inelastic collisions are of two types, head-to-tail and head-to-head. Head-to-tail collisions of dipoles result in longitudinal aggregation while head-to-head collisions promote aggregation in the transversal direction. The frequency of head-to-head collisions is set by the impact parameter that allows one to control the resulting shape of aggregates, their anisotropy and fractal dimension.