Dielectric properties of twist grain boundary phases: influence of the anchoring and the distance between grain boundaries.
The dielectric properties of the twist grain boundaries TGB(A) and TGB(C) of liquid crystal phases differ from the smectic-A and smectic-C phase ones: a theoretical model confirmed by experimental results shows that the Goldstone mode of the TGB(C) phase and the soft mode of the TGB(A) phase are strongly reduced. This behavior is due to elastic strain, which is connected to two parameters: the anchoring at the grain boundaries and the distance between the grain boundaries. It is shown quantitatively that a relatively flexible anchoring in the TGB(A) phase becomes rigid in the TGB(C) one. The relaxation frequencies of these modes allow analysis of the rotational viscosity variations.
Ismaïli
M
M
Laboratoire de Dynamique et Structure des Matériaux Moléculaires, ESA CNRS 8024, Université de Lille 1, F-59655 Villeneuve d'Ascq Cedex, France. Mimoun.Ismaili@univ-lille1.fr
Bougrioua
F
F
Isaert
N
N
Legrand
C
C
Nguyen
H T
HT