Thermotropic Liquid Crystal Properties of Alkylammonium Alkanesulfonates

Abstract

Abstract Alkylammonium methane-, ethane-, 1-propane-, and 1-butanesulfonates exhibit a smectic A phase when the cation carries a dodecyl or longer alkyl group. The temperature range of the existence decreases in the following order: methanesulfonates>1-propanesulfonates>ethanesulfonates>1-butanesulfonates. In the last series, the mesophase is entirely metastable. The layer spacing in the 1-propanesulfonate is shorter by about 0.30 nm than that of the corresponding methanesulfonate, even though the alkyl chain length in the anion is increased by 0.25 nm.