Molecular arrangement in a chiral smectic liquid crystal cell studied by polarized infrared spectroscopy

Molecular Structure of a Partly Deuterated Chiral Smectic Liquid Crystal Studied by Polarized FTIR Spectroscopy

“…A. Sigarev et al the observed differences in the IR absorption anisotropy of the phenyl and the carbonyl bands has confirmed unambiguously the existence of biasing in the rotational orientational distribution of the "chiral" carbonyl groups with respect to the molecular long axes in ferroelectric liquid crystals (FLCs) [2][3][4][5][7][8][9][10]. This effect of biasing is considered to be a cause of the origin of the spontaneous polarization in FLCs.…”

“…The planar homogeneously aligned cells with helical or field unwound structures of FLCs usually exhibit a comparatively high dichroism of the phenyl peak at a wavenumber ∼1600 cm −1 (the transition moments of the respective vibrations usually make polar angles less than 20 • with the molecular long axis) [1][2][3][4][5][7][8][9][10]. However, considerably lower dichroism is observed for the carbonyl bands in the spectral range 1700-1800 cm −1 and especially for the methylene bands observed in the range 2800-3000 cm −1 .…”

“…The molecular arrangements in anisotropic samples of chiral smectic liquid crystals (LCs) can be studied in detail using polarized Fourier-transform infrared (FTIR) spectroscopy since the absorbance profiles of characteristic absorption bands are sensitive to the orientational distributions of their vibrational transition moments [1][2][3][4][5][6][7][8][9][10]. An IR beam of rather low intensity usually used in FTIR spectrometers enables one to examine the molecular orientations in various smectic phases and to observe the structural transformations in LC samples caused by changes in temperature or external fields non-destructively.…”

Anisotropic network formation by the photopolymerization of new monomers derived from 4‐hydroxybenzenethiol

“…Moreover, the molecular orientation in some specific parts of the molecules can be determined by Fourier transform infrared (FTIR) dichroism. 13 Diacrylate monomers are among the most studied because of their versatility in synthesis, which enables structural modifications, and the possibility of crosslinking at different temperatures. In addition, these monomers allow the preparation of organized networks with high order parameters, high birefringence, and good substrate adhesion.…”

Chiral smectic-Aand smectic-Cphases with de Vries characteristics

“…4(a) and 4(b), for different values of the applied dc voltage. A unique absorbance profile is constructed for each applied voltage and is fitted to the equation [20][21][22] A( p ) = −log 10 [10 −A + (10…”