Effective pair interactions between colloidal particles at a nematic-isotropic interface

TL;DR

This paper theoretically investigates the complex interactions between colloidal particles at a nematic-isotropic interface, revealing non-monotonic potentials, defect-related hysteresis, and proposing an empirical model for these interactions.

Contribution

It introduces a theoretical analysis of colloid interactions at nematic-isotropic interfaces, highlighting non-monotonic potentials and defect dynamics, with an empirical model for effective interactions.

Findings

Interaction potential is non-monotonic

Force-distance curves show jumps and hysteresis

Proposed simple empirical pair potential

Abstract

The Landau-de Gennes free energy is used to study theoretically the interaction of parallel cylindrical colloidal particles trapped at a nematic-isotropic interface. We find that the effective interaction potential is non-monotonic. The corresponding force-distance curves exhibit jumps and hysteresis upon approach/separation due to the creation/annihilation of topological defects. Minimization results suggest a simple empirical pair potential for the effective colloid-colloid interaction at the interface. We propose that the interface-mediated interaction can play an important role in self-organization and clustering of colloidal particles at such interfaces.