Nonlinear dielectric effect of critical liquid mixtures: Propylene carbonate + monoalkylbenzene systems

The nonlinear dielectric effect (NDE) is measured in the one-phase region of propylene carbonate + monoalkylbenzene systems. The deviations from the regular molecular behavior are determined by the reference solution method at a very wide temperature distance, up to 180 K, from the critical point. The data are analyzed under the assumption of the universality of the precritical NDE by making use of empirical crossover functions. The precritical NDE anomalies are large. The critical exponent ψ=0.396±0.01 and the correction exponent Δ=1.02±0.1 both differ from the theoretical values.