Static and dynamic dielectric behavior of mesogenic compounds of different polarity in the vicinity of the isotropic to nematic phase transition.
Mesogenic compounds belonging to the two well-known -cyanophenyl, and -isothiocyanatophenyl homologous series, which distinctly differ in the molecular polarity (-C identical with N, 5D; -N=C=S, 2.5D), show an essential difference in the pretransitional dielectric behavior in the vicinity of the isotropic to nematic (I-N) phase transition. Taking into account the results presented in Phys. Rev. E 67, 041705 (2003), the features of the I-N transition observed for the less polar mesogens are characteristic for the first order phase transition, whereas in the case of the strongly polar ones, the I-N transition is undoubtedly close to the second order.
Faculty of Electrical Engineering, University of Sts. Cyril-Methodius, P.O. Box 574, 91000 Skopje, Macedonia.
Margarita
M
Ginovska
Horst
H
Kresse
Danuta
D
Bauman
Grzegorz
G
Czechowski
Jan
J
Jadzyn