Cubic Phases of 4'-n-docosyloxy-3'-nitrobiphenyl-4-carboxylic Acid (ANBC-22)

Abstract

Dilatometric experiments have been performed on 4′-n-docosyloxy-3′-nitrobiphenyl-4-carboxylic acid (ANBC-22) which exhibits two types of thermotropic cubic phases (Cub I and II) on heating. Although the unit lattices of both Cub I and II, determined by X-ray diffraction measurements, slightly but certainly shrink with increasing temperature, the thermal expansion coefficients in both temperature regions were found to be positive. Thus, this study provided an experimental evidence that the number of molecules constructing the unit lattice of the two Cub phases decreases with temperature. Some aspects of the structural features of the Cub phases are discussed.