Abstract
Heat capacity of a thermotropic mesogen ANBC(22) -alkoxy--nitrobiphenyl-4-carboxylic acid with 22 carbon atoms in alkyl chain) showing two cubic mesophases was measured by adiabatic calorimetry between 13 and 480 K. Excess enthalpies and entropies due to phase transitions were determined. A small thermal anomaly due to the cubic phase transition was successfully detected. Through an analysis of chain-length dependence of the entropy of transition, the sequence of two cubic mesophases (with space groups Ia3d and Im3m) is deduced for thermotropic mesogens It is shown that the disorder of the core arrangement decreases in the order of while that of the chain in the reverse order cubic
- Received 13 June 2001
DOI:https://doi.org/10.1103/PhysRevE.65.031719
©2002 American Physical Society