Electric-field-induced reorientation of liquid crystalline p-cyanophenyl-p-n-alkylbenzoates: A time-resolved study by Fourier transform infrared transmission and attenuated total reflection spectroscopy.
In: Applied Spectroscopy (Appl.Spectrosc.), Jg. 57 (2003) ; Nr. 5, S. 499-505
Zeitschriftenaufsatz / Fach: Chemie
Time-resolved polarization FTIR transmission and attenuated total reflection (ATR) spectroscopy were applied to study the reorientation phenomena of the three members of the homologous series of nematic liq. cryst. p-cyanophenyl-p-n-alkylbenzoates 6CPB, 7CPB, and 10CPB under the external perturbation of an elec. field. In conjunction with a newly constructed measurement cell, this method allowed one to differentiate the response of the LC system in the surface layer and in the bulk of the cell at different temps. and voltages. The relaxation time of the LC mols. close to the wall of the cell is shorter than in the bulk. However, at a field strength of 7 V, the initial orientation in the bulk precedes the analogous process in the surface region.