Director configuration of liquid crystals in a cylindrical cavity with homeotropic anchoring conditions

Abstract

We study numerically the equilibrium configurations of nematic liquid crystals confined in cylindrical cavities with strong and weak homeotropic anchoring conditions, respectively, on the basis of the elastic continuum theory and the difference iterative method. The lyotropic chromonic liquid crystal disodium cromoglycate exhibits a completely different spontaneous chiral configuration from 5CB due to the large ratio of the saddle-splay elastic constant to the twist elastic constant. We show that how the elastic constants affect the director alignment in chiral structure with strong homeotropic anchoring conditions. For the weak homeotropic anchoring conditions, the theoretically predicted transition from a twisted and escaped radial to an escaped twisted configuration of DSCG and the transition from an escaped radial to a UA configuration of 5CB, on reduction of the anchoring coefficient below a certain threshold, are confirmed to occur at A∼10−8J/m2. Remarkably, it provides a more accurate theoretical analysis for the prediction of director configurations in cylindrical cavities under different conditions in experiments.