High-Resolution Adiabatic Calorimetry Measurements in the Vicinity of the Liquid Crystal Phase Transitions

High-resolution adiabatic calorimetry has been used for the study of the liquid_crystal phase transitions in mixtures of 4-n-hexyloxyphenyl-4″-n-octyloxybenzoate (), 4-n-hexyloxy-phenyl-n-decyloxybenzoate () and 4-n-hexyloxyphenyl-4″-n-dodexyl-oxybenzoate () with emphasis on the vicinity of the NAC (nematic-smectic A-smectic C) multicritical point and the tricritical point along the NA (nematic-smectic A) line. Our results demonstrate the fluctuation nature of both these multi-critical points.