Brillouin scattering investigations of liquid crystal ME6N/CCl4 mixtures

We present the results of a Brillouin scattering experiment performed on mixtures composed by a thermotropic liquid crystal, ME6N (4-cyanophenyl-4’-hexylbenzoate) and carbon tetrachloride. Recently, we showed1 how the excess thermodynamic properties observed in some binary mixtures are mainly originated by excluded volume effects. Within this scenario some thermodynamic properties of the mixture can be successfully described using a primitive model based on hard sphere potential with non-additive diameters. ME6N/CCl4 system represents a good experimental test-bed for extending this approach to mixtures with elongated molecules. To this purpose we have compared the experimental adiabatic compressibility and the excess volumes with the theoretical predictions obtained by using as a model a mixture composed by elongated and spherical particles interacting through a hard-core potential.