Mesomorphic behaviour of N-(n-alkyl) pyridinium hydrogensulfates

Abstract The mesophase behaviour of homologues N -( n -alkyl) pyridinium hydrogensulfates has been examined by thermal and optical studies. These cationic surfactants not only form thermotropic mesophases at relatively low temperatures (about 100°C), but also form lyotropic mesophases in the unconventional solvent concentrated sulphuric acid. The sequences of lyotropic liquid crystalline phases have been determined.