Theory of nematic ordering induced by the hydrogen bonding between rod and solvent molecules

Abstract

A mean-field theory is introduced to describe nematic (N) ordering and phase separations in aqueous low-molecular-weight liquid crystalline molecules. We consider a physical bonding (or a hydrogen bonding) between the rod and solvent (water) molecules. Our theory predicts that the hydrogen bonds between the unlike molecules stabilize the N phase and take novel phase separations on the temperature-concentration plane. Upon increasing the number of functional groups on the rods and forming the physical bond with the solvent molecule, the stable N phase region is broadened on the phase diagram. We also find a miscibility window of the N phase and closed-loop coexistence curves with upper and lower critical solution temperatures near the N phase.