Non-linear dielectric effect in superpressed chiral isopentylcyanobiphenyl (5 [formula omitted]CB)

Abstract

Results are presented of linear and non-linear dielectric studies in pressurized isopentylcyanobiphenyl (5 ∗ CB). Temperature studies of linear dielectric relaxation in 5 ∗ CB showed the Vogel–Fulcher–Tammann evolution of relaxation times and the broadening of loss curves on cooling [J. Chem. Soc. Farad. Trans. 94 (1998) 387; Phys. Chem. Chem. Phys. 1 (1999) 4843]. The behavior characteristic for glassy liquids was also found in the presented preliminary tests of dielectric relaxation in pressurized 5 ∗ CB. For pressure dependencies for maxima of loss curves and for the static dielectric permittivity additional pretransitional anomalies was found. They may be associated with premesomorphic fluctuation (inhomogeneities) in the isotropic (fluid-like) surrounding. The stationary response of strong electric field induced changes of dielectric permittivity (NDE) also exhibited a singular behavior. It was found that NDE decreased strongly towards negative values on pressuring. This is a novel behavior which can be hardly explained by classic models developed for normal liquids [Dielectric Physics, PWN–Elsevier, Warsaw, 1980 and 1993].