Author/Editor     Čepič, Mojca; Gorecka, E; Pociecha, D; Žekš, Boštjan; Nguyen, HT
Title     Theoretical and experimental study of the intermediate Sm C*(Fl2) and the Sm C*(Fl1) phases in antiferroelectric liquid crystals
Type     članek
Source     J Chem Phys
Vol. and No.     Letnik 117, št. 4
Publication year     2002
Volume     str. 1817-26
Language     eng
Abstract     Within the new phenomenological model of antiferroelectric liquid crystals, structures of the two phases, the Sm C*F/2 and the Sm C*F/1„ that appear in the temperature range between the Sm C* and the Sm C*A phase, are found. The structure of the Sm C*F/2 and the Sm C*F/1phases is consistent with extensive optical, electro-optic, and dielectric measurements performed on the liquid crystal R-100TBBB 1 M7, for which resonant x-ray scattering studies have previously proven that these two phases have the three-layer (Sm C*F/1) and the four-layer (Sm C*F/2) periodic structure, respectively. The biaxiality of the four-layer structure of the Sm C*F/2 phase is directly observed experimentally for the first time at the temperature where the optical pitch is unwound. The theoretical model allows for experimentally consistent phase sequence, the order of transitions, and the temperature dependence of optical properties including the optical helicoidal modulation inversion within the temperature range of the Sm C*F/2 phase.
Descriptors     BIOPHYSICS
ELECTROMAGNETIC FIELDS
CRYSTALLIZATION
MODELS, THEORETICAL