Thermodynamic parameters and their variation with temperature and chain length in a number of symmetric dimeric liquid crystals

Different thermodynamic parameters are estimated for the first time in the case of a number of symmetric dimeric liquid crystals, (DLCs), from the thermal expansion coefficient, α computed from the density data in isotropic as well as in liquid crystalline phases. Further, the parameters like the molecular free length, Lf, the molecular radius, Mr and the nonlinearity parameter, B/A are also estimated from α in the above compounds. All these parameters are obtained either with the temperature in an individual compound or either with the spacer length or with the end alkyl chain number. The results are discussed with the body of the data available on the corresponding monomers and other monomer liquid crystalline compounds. The molecular radius is estimated from both the density and the birefringence data.