Heat-capacity studies near the smectic-C"smectic-I transition of two liquid-crystal compounds

Detailed heat-capacity studies have been carried out in the vicinity of the smectic-C"smectic-I transition of two liquid-crystal compounds in the homologous series of racemic 4-(2-methylbutyl)phenyl-4-n-alkyloxybiphenyl-4- carboxylate (2M4PmOBC or mOSI). In contrast to the continuous smectic-Ahexatic-B transition found in many members of n-alkyl-4-n-alkyloxybiphenyl-4-carboxylate (nmOBC) with symmetric and sharp heat-capacity anomalies, asymmetric and rounded ones are observed in the smectic-Csmectic-I transitions of both 2M4P8OBC and 2M4P9OBC.