Pseudo-critical behavior on the partial molar volume of solutes in the isotropic phase of liquid crystal

Temperature dependence of partial molar volume of 4-amino-4′-nitrobiphenyl (ANB) and 4,4′-dinitrobiphenyl (DNB) in the isotropic phase of 4-n-pentyl-4′-cyanobiphenyl (5CB) was determined. Addition of ANB to 5CB causes increase of isotropic–nematic phase transition temperature (TIN) [1]. The decrease of partial molar volume of ANB was observed while the increase of partial molar volume of DNB and triphenyl phosphite (TPP) [8] was observed with approaching TIN. The anomalous behavior of partial molar volume was discussed using treatments similar to that of other thermodynamic derivatives in the I–N transition.