Abstract
It has been shown that the temperature behavior of dielectric permittivity () in the isotropic phase of nematogens can be described in the same way as in critical binary solutions. Hence, using a relation with the critical exponent it was possible to portray the results of measurements in the isotropic phase of 5-heptyl-2-(4′-cyanobiphenyl)-pyrimidine and 4,4--octylcyanobiphenyl. The influence of the position of the permanent dipole moment on the results was tested by additional measurements in -(-methoxybenzylidene)--butylaniline. It also has been shown that a fluidlike analogy can be applied to the nonlinear dielectric effect (NDE), which describes changes of dielectric permittivity induced by a strong electric field. Measurements were conducted for the lowest frequency used in NDE studies ( kHz), so the condition (with the relaxation time) was always fulfilled. Values of discontinuities of the isotropicnematic phase transition from both the analysis of measurements and NDE studies are in good agreement.
- Received 4 June 1996
DOI:https://doi.org/10.1103/PhysRevE.54.6452
©1996 American Physical Society