Annihilation dynamics of stringlike topological defects in a nematic lyotropic liquid crystal

TL;DR

This study investigates the annihilation dynamics of topological defects in a lyotropic nematic liquid crystal, revealing a specific scaling law and extending experimental understanding beyond thermotropic and polymeric liquid crystals.

Contribution

It provides the first experimental analysis of defect annihilation in lyotropic nematic liquid crystals, confirming a scaling law and aligning with previous theoretical and experimental results.

Findings

Scaling law D ~ t^{0.39} for defect separation

Good quantitative agreement with prior studies

Extends defect dynamics research to lyotropic systems

Abstract

Topological defects can appear whenever there is some type of ordering. Its ubiquity in nature has been the subject of several studies, from early Universe to condensed matter. In this work, we investigated the annihilation dynamics of defects and antidefects in a lyotropic nematic liquid crystal (ternary mixture of potassium laurate, decanol and deionized-destilated water) using the polarized optical light microscopy technique. We analyzed Schlieren textures with topological defects produced due to a symmetry breaking in the transition of the isotropic to nematic calamitic phase after a temperature quench. As result, we obtained for the distance D between two annihilating defects (defect-antidefect pair), as a function of time t remaining for the annihilation, the scaling law D ~ t^{\alpha}, with \alpha = 0.390 and standard deviation \sigma = 0.085. Our findings go in the direction to extend experimental results related to dynamics of defects in liquid crystals since only thermotropic and polymerics ones had been investigated. In addition, our results are in good quantitative agreement with previous investigations on the subject.