The Impact of Liquid Crystalline Phase Ordering on the Thermodynamic Scaling of Itraconazole

Herein, we tested the validity of the thermodynamic scaling of two (α and δ) relaxation processes observed in the isotropic and nematic phases of itraconazole, that is classified as a liquid crystal (LC). As illustrated, relaxation times of both processes obtained at various thermodynamic conditions can be successfully superposed over 1/TVγ with different scaling exponents, γ, satisfying the thermodynamic scaling law. However, it was found that γ parameters determined in the isotropic phase are higher than those estimated for respective relaxation processes in the nematic state [J. Chem. Phys. 2015, 142, 224507]. It seems that differences in the arrangements of molecules within LC phases significantly affect the effective intermolecular potential resulting in the variation of scaling exponent and disagreement between γ and γEOS (estimated from the equation of state). The observed behavior suggests that both variables depend not only on the intermolecular potential but also on the degree of molecular ordering.