Inverse gas chromatography study of the thermodynamic behaviour of thermotropic low molar mass and polymeric liquid crystals

We report measurements of activity coefficients and derived excess partial molar enthalpies and entropies of mixing for 17 hydrocarbon probes in three low molar mass liquid crystals as well as a polymeric version containing the same mesogenic group. Values were obtained in the isotropic liquids and in N, SmA, SmC, and N* mesophases. The results are interpreted in terms of a qualitative, descriptive model accounting for the various contributions to the energetics and the entropic effects of probe-LC interactions. The behaviour of the LC polymer was found to be determined largely by the interactions with the mesogen while the polymer backbone had a relatively minor effect.