Thermo acoustic parameters in the nematic and isotropic phases of 5CB and tetraethyl methane in 5CB

The addition of non-rod like solute impurity to a liquid crystalline solvent leads to some exciting results such as depression of nematic-isotropic transition temperature and the formation of two-phase region. In view of this, specific volume and thermal expansion studies in the nematic and isotropic phases of p-n-pentyl-p1-cyanobiphenyl (5CB) and dilute solution of the quasispherical solute tetraethyl methane were considered. From these results thermo acoustic parameters such as isochoric temperature coefficient of internal pressure (X), isochoric volume expansivity (X1), the reduced compressibility (β∼), the reduced volume (V∼), isothermal microscopic Gruneisen parameter (Γ), Huggins parameter (F), fractional free volume (f) and Sharma parameter (So) are estimated both in nematic and isotropic regions. Using the data given by Oweimreen et al. [G.A. Oweimren, A.K. Shihab, K. Halhouli, S.F. Sikander, Mol. Cryst. Liq.Cryst. 138 (1986) 327] variations of these thermo acoustic parameters with temperature and two phase region are critically examined.