A study on the twisted-escape radial configuration of lyotropic chromonic liquid crystals confined to cylinders

Nematic liquid crystals commonly exhibit escape radial configuration when confined to cylinders with normal surface anchoring. Lyotropic chromonic liquid crystals confined to cylinders exhibit a departure from the escape radial configuration by developing a twist distortion. This symmetry-breaking configuration is distinguished by its birefringence pattern with an increase of the transmitted intensity in the center of the cylinder. The length distribution and the average length of chromonic aggregates were estimated from a model for self-assembling systems. The contrasting scaling of splay and bend elastic modulus with aggregation length leads to the changes in the director field and the birefringence pattern. For high concentrations, we observed a co-existence of the twisted escape radial configuration with the doubly twisted configuration. The anchoring violation in doubly twisted domains is rationalized by the weak anchoring strength which is overcome by means of the saddle splay contribution to the free energy. Our experiments enable the estimation of the normal anchoring strength with the help of numerical calculations.