Light-induced pitch transitions in photosensitive cholesteric liquid crystals: Effects of anchoring energy
ORLOVA, Tetiana N.
Laboratoire Ondes et Matière d'Aquitaine [LOMA]
Institute of Physics [Kiev] [IOP]
Laboratoire Ondes et Matière d'Aquitaine [LOMA]
Institute of Physics [Kiev] [IOP]
ORLOVA, Tetiana N.
Laboratoire Ondes et Matière d'Aquitaine [LOMA]
Institute of Physics [Kiev] [IOP]
< Leer menos
Laboratoire Ondes et Matière d'Aquitaine [LOMA]
Institute of Physics [Kiev] [IOP]
Idioma
en
Article de revue
Este ítem está publicado en
Physical Review E : Statistical, Nonlinear, and Soft Matter Physics. 2014-01-06, vol. 89, n° 1, p. 012503 (1-10)
American Physical Society
Resumen en inglés
We experimentally study how the cholesteric pitch, $P$, depends on the equilibrium one, $P_0$, in planar liquid crystal (LC) cells with both strong and semistrong anchoring conditions. The cholesteric phase was induced by ...Leer más >
We experimentally study how the cholesteric pitch, $P$, depends on the equilibrium one, $P_0$, in planar liquid crystal (LC) cells with both strong and semistrong anchoring conditions. The cholesteric phase was induced by dissolution in the nematic LC the right-handed chiral dopant 7-DHC (7-dehydrocholesterol, provitamin $D_3$) which transforms to left-handed tachysterol under the action of UV irradiation at the wavelength of 254 nm. By using the model of photoreaction kinetics we obtain dependencies of isomers concentrations and thus the equilibrium pitch on UV irradiation dose. The cholesteric pitch was measured as a function of irradiation time using the polarimetry method. In this method, the pitch is estimated from the experimental data on the irradiation time dependence of the ellipticity of light transmitted through the LC cells. It is found that the resulting dependence of the twist parameter, $2 D/P$ ($D$ is the cell thickness), on the free twisting number parameter, $2 D/P_0$, shows the jump-like behaviour and agrees well with the known theoretical results for the anchoring potential of the Rapini-Papoular form.< Leer menos
Palabras clave en inglés
Surface phenomena
Light-sensitive materials
Transitions in liquid crystals
Liquid crystals
Orígen
Importado de HalCentros de investigación