Phase behaviors of ternary mixtures of liquid crystals, three series of trans-4-n- alkylcyclohexane carboxylic acid cyanophenol ester [alkyl = propyl(C3), butyl(C4), pentyl(C5)] and trans-1-n- butyl-4- (4'-cyanophenyl) cyclohexane [PCH4], were investigated with DSC and Polarizing microscope, and the solid- mesophase transition temperatures were calculated with the incorporation of activity coefficients in mesophase.
The binary phase diagrams of five typical systems showed the eutectic behaviors and the observed nematic ranges were broadest near the eutectic composition. For ternary mixture systems of C3-C4-C5 and PCH4-C3-C5, its eutectic temperatures appeared at 15.0 and $6.4\,^\circ\!\C$, respectively.
The crystal to nematic transition ranges were calculated by UNIQUAC model of the interaction and structural parameters. Using binary parameters, the ternary eutectic points were evaluated and good agreements were demonstrated for binary and ternary mixtures such as C3, C4, C5 and PCH4.
Ternary mixtures, C3-C4-C5 and PCH4-C3-C5, typically showed the schlieren texture of nematic liquid crystal above the solid-mesophase transition temperature.