Chiral structures and defects of lyotropic chromonic liquid crystals induced by saddle-splay elasticity

TL;DR

This study investigates how saddle-splay elasticity influences the director configurations and defect structures in lyotropic chromonic liquid crystals confined in cylindrical geometries, revealing inhomogeneous states and defect preferences.

Contribution

It provides experimental and theoretical insights into the effects of saddle-splay elasticity on LCLC configurations, including the identification of inhomogeneous states and defect behaviors.

Findings

Ground state becomes inhomogeneous when saddle-splay modulus exceeds twice the twist modulus.

Large saddle-splay modulus observed, violating Ericksen inequalities but maintaining stability.

Point defects are favored over domain walls between opposite-handed domains.

Abstract

An experimental and theoretical study of lyotropic chromonic liquid crystals (LCLCs) confined in cylinders with degenerate planar boundary conditions elucidates LCLC director configurations. When the Frank saddle-splay modulus is more than twice the twist modulus, the ground state adopts an inhomogeneous escaped-twisted configuration. Analysis of the configuration yields a large saddle-splay modulus, which violates Ericksen inequalities but not thermodynamic stability. Lastly, we observe point defects between opposite-handed domains and explain a preference for point defects over domain walls.