We have carried out a numerical study of both the structural and thermodynamic properties of free-standing smectic films (FSSFs) for two cases of enhanced pair interactions in the bounding layers. Calculations, based upon the extended McMillan’s approach with anisotropic forces, shows a stepwise reduction of the value of the heat capacity as the temperature is raised above the bulk smectic A-isotropic transition. The effects of surface “enhanced” pair interactions in the bounding layers and of film thickness on the orientational and translational order parameters, the Helmholtz free energy, and entropy of FSSFs have also been investigated. Reasonable agreement between the theoretically predicted and the experimentally obtained—by means of calorimetric techniques—data on the heat capacity of the partially fluorinated$5-n-\text{alkyl}-2-(4-n-(\text{perfluoroalkyl}-\text{metheleneoxy}\left)\text{phenyl}\right)$ (H10F5MOPP) films has been obtained.

• Received 24 November 2009

DOI:https://doi.org/10.1103/PhysRevE.82.041704