Cylindrical growth of smectic A liquid crystals from the isotropic phase in some binary mixtures

(Received 25 October 1991, accepted 28 November 1991)

Abstract
In some binary mixtures of smectogenic and non-mesomorphic aliphatic compounds, the smectic A phase separates in the form of cylindrical structures. Our observations on some of these systems indicate that such structures are stabilised by a negative radial concentration gradient of the non-mesomorphic component. If the concentration of the non-mesomorphic component is allowed to increase in the isotropic phase, the cylindrical structures develop an undulation instability. It is argued that the concentration gradient leads to a spontaneous curvature in the smectic layers, which makes it necessary to include a term linear in curvature in the elastic energy density of such systems.