Heat-capacity study of phase transitions in the liquid-crystal racemic 4-(2′-methylbutyl)phenyl-4′-n-nonyloxybiphenyl-4-carboxylate (2M4P9OBC)

The heat capacity of racemic 4-(2′-methylbutyl)phenyl-4′-n-nonyloxybiphenyl-4-carboxylate (2M4P9OBC) has been measured in the vicinity of the Sm C-SmI, SmI-Sm G, and Sm G-SmH phase transitions. The nature of the Sm C-SmI transition will be discussed in the context of known microscopic pictures of each phase. In contrast to the continuous SmA-hexatic-B phase transition found in n-hexyl-4′-n-pentyloxybiphenyl-4-carboxylate, an asymmetric heat-capacity anomaly is identified in the Sm C-SmI transition of 2M4P9OBC.