Short-Range Order Fluctuation in the Isotropic Phase of Solutions of 4-trans-4′-n-dodecylcyanobiphenyl in Benzene Studied by Nonlinear Dielectric Spectroscopy

Nonlinear dielectric spectroscopy is used to study the dynamics of the smectogenic compound 4-trans-4′-n-dodecylcyanobiphenyl in the isotropic phase as a function of its concentration in benzene. The results obtained reveal that the large, positive amplitude of the field-induced dielectric increment (∆ε ≈ 10−3) and its frequency dependence observed in the nonlinear dielectric effect spectra, even far from the possible isotropic–smectic A type phase transition, are due to short range fluctuations of the electric moment. The nature of molecular formations as a result of the strong intermolecular orientational correlations is discussed.