Nuclear Magnetic Resonance Measurements on a Macroscopically Ordered Smectic Liquid Crystalline Phase

Abstract

OF the three types of liquid crystalline phases, the smectic type can be formed in some compounds by either varying the temperature (thermotropic mesophases) or the solvent concentration (lyotropic mesophases). The system we used belongs to the latter type and consisted of a solution of potassium oleate (KO) in D₂O. According to Luzzati et al.¹, a concentration above 72 per cent by weight of KO in water yields a smectic mesophase at room temperature (20° C). In such a system the soap-like molecules can form a lamellar domain structure, and in these domains the direction of the molecular maximum and minimum polarizability perpendicular to the molecular chains is at random. This results in an ordered structure with an optical uniaxial character having its optical axis perpendicular to the lamellae.