Thermotropic Ionic Liquid Crystals VI. Structural Parameters of Solid and Liquid Crystal Phases of Anhydrous Short-Chain Sodium Alkanoates

Abstract

Unit cell constants were determined from powder X-ray diffraction photographs taken of several anhydrous short-chain sodium alkanoates at room temperature. The temperature dependence of the bilayer spacing in the alkanoates was determined over the range 25-300°C. Overall changes in bilayer spacings between the solid and the neat phase were found to be much smaller than in long-chain alkanoates. A correspondence was noted between the room temperature lateral packing area and the ²³Na quadrupole coupling constant in the mesophase. The mcsophase bilayer spacing was consistent with a structural model in which the tilted anion chain rotates on a cone.