Thermal and Mechanical Instabilities in Nonaqueous Lamellar Lyotropic Lecithin-Ethylenglycol

Abstract

A method for preparation of homeotropic monodomains of the lamellar lyomesophase of synthetic DL-β - -γ-dilauroyl-α-lecithin plus ethylenglycol is developed. It implied a slow growth of monodomains from the isotropic melt, between two silane-fueated glass plates. Compression and curvature elastic constants of such monodomains are measured from the observation of thermally and mechanically induced undulation instabilities. The penetration length, measured by quasielastic Rayleigh scattering of light, compares with the layer thickness measured by X-rays. This lyomesophase provides a good example of a room temperature smectic-A like liquid crystal with a very broad range of thermal stability.