Nonlinear Dielectric Effect Behavior in a Critical and Near-Critical Binary Mixture

Abstract

Experimental results are presented of the nonlinear dielectric effect (NDE) studies in the homogeneous phase of critical and near-critical binary mixtures. Both the stationary NDE and the related dynamic properties are discussed. In a critical mixture the NDE stationary response is described by a critical exponent ψ≈0.4 near the critical consolute temperature (T c ) and ψ≈0.6 remote from T C . For the non-critical mixture the exponent describing the temperature behavior near T C decreases down to ψ≈0.1 The temperature behavior of the NDE decay after switching off a strong electric field is described by the exponent y≈1.3 for a critical mixture and y→1 for a non-critical mixture. The possible explanation of the observed phenomena is proposed. It assumes the appearance of a quasi-nematicstructure induced the external field, leading to the appearance of mean-field properties in the vicinity of T C The possible relationship with the behavior observed in a critical mixture under shear-flow, for instance when testing the anomaly of shear viscosity, is also shown.KeywordsCritical ExponentStrong Electric FieldBinary Liquid MixtureDroplet ModelCritical FluctuationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.