Critical fluctuations near the smectic-<i>A</i>–smectic-<i>C</i>transition of a partially perfluorinated compound

Abstract

Utilizing our high-resolution bulk and free-standing film calorimeters, we have conducted detailed heat-capacity measurements near the smectic-A--smectic-C phase transition of one partially perfluorinated liquid-crystal compound. The thin film data clearly demonstrate the importance of fluctuations due to reduced dimensionality. Moreover, the data from bulk samples and thick films cannot be adequately fit using the customary extended mean-field model. Successful fitting requires the inclusion of terms characterizing Gaussian fluctuations.