Orientation Dependent Interaction and Self-assembly of Cubic Magnetic Colloids in a Nematic Liquid Crystal

TL;DR

This study explores how cubic magnetic colloids in nematic liquid crystals interact and self-assemble based on their orientation, revealing diverse structures and magnetic properties useful for advanced material design.

Contribution

It provides the first experimental analysis of orientation-dependent interactions and self-assembly of cubic magnetic colloids in nematic liquid crystals, highlighting their potential for functional magnetic materials.

Findings

Colloidal interactions depend on cube orientation.

Cubes form diverse structures like chains and loops.

Magnetic moments measured via elastic and magnetic torque balance.

Abstract

Spherical microparticles dispersed in nematic liquid crystals have been extensively investigated in the past years. Here, we report experimental studies on the elastic deformation, colloidal interaction and self-assembly of hematite microcubes with homeotropic surface anchoring in a nematic liquid crystal. We demonstrate that the colloidal interaction and self-assembly of cubic colloids are orientation dependent. In a notable departure from the conventional microspheres, the microcubes stabilise diverse structures, such as bent chains, branches, kinks and closed-loops. The microcubes reorient under rotating external magnetic field, thereby experiencing an elastic torque in the medium, which allows us to measure the magnetic moment through competition between elastic and magnetic torques. Our findings envisage that the faceted magnetic colloids in liquid crystals are potential for developing new functional magnetic materials with specific morphologies.