Abstract
An electric field hysteresis of the light transmittance of the (polymer / liquid crystal) composite should be strongly related to the electric field hysteresis of the polar anchoring strength for orientation of nematic liquid crystalline molecules at the (polymer / liquid crystal)interface. When the nematic liquid crystal in a homeotropic alignment was sandwiched between physically isotropic polymer layer and substrate, the Schlieren texture and the singular surface disclination (Bloch wall) were observed under polarizing optical microscope. The magnitude of the polar anchoring strength, A
polar was evaluated by measuring the width of the Bloch wall, e. The magnitudes of A
polar were evaluated for three types of the (poly(alkylisopropyl fumarate)s / liquid crystal) cells. It was clarified from the time dependence of e after the application of an electric field that the othe two poly(n-alkylisopropyl fumarate)s have smaller A
polar and longer relaxation time of A
polar than poly(diisopropyl fumarate). It was concluded that the magnitude of A
polar and the relaxation time of A_<polar> were decreased with an increase of the thermal mobility of polymer side chain.
