String Formation and Arrested Ordering Kinetics in Nematics Induced by Polar Particles

TL;DR

This study investigates how polar particles influence the formation and dynamics of defect structures in nematic liquid crystals, revealing how coupling strength and particle density affect string formation and defect kinetics.

Contribution

It introduces a coarse-grained model showing how polar particles induce string-like defect structures and alter ordering kinetics in nematic systems.

Findings

Stronger coupling leads to sharper strings connecting defects.

Increased polar particle density enhances defect dynamics.

Larger coupling causes delayed coarsening in ordering.

Abstract

Our study explores the mixture of polar particles in apolar environment. We employ a coarse-grained approach to model the mixture, where polar particles are in minority. The interaction between polar and apolar components is incorporated via a coupling term in the free energy. Coupling generates local interaction in the system which results in the formation of string like structures connecting a pair of half integer topological defects. The increase in the coupling strength or the density of polar particles results in the: Sharper strings with larger probability of connecting the topological defects of same charge and the enhanced dynamics of topological defects. However, the ordering kinetics of the system shows the delayed coarsening for larger coupling or polar density. Our results can be used to develop controlled kinetics as well as to detect the impurities in liquid crystals.