Synthesis and characterization of smectic polymorphism in higher homologues of N-(p-n-alkoxybenzylidene)-p-n-(alkylanilines)

Higher homologues of N-(p-n-alkoxybenzylidene)-p-n-alkylanilines (nO.m) compounds with n = 15 and 18 and m =4 to 10, 12, 14, and 16 have been synthesized and the smectic polymesomorphism is studied. The transition temperatures were obtained both from thermal polarizing microscopy and differential scanning calorimetry. The compounds exhibit a smectic-F phase from the isotropic melt, their amount increasing with the number of the alkoxy chain. This implies that with the alkoxy chain number the manifestation of smectic-F occurs with shorter alkyl chain. The phase variants were confirmed with miscibility studies.