We observed light-induced alignment of the nematic liquid crystal, 4,4′−n−pentylcyanobiphenyl (5CB), on a fused quartz. Irradiation of the adsorbed layer with polarized ultraviolet light produced homogeneous alignment in a 5CB-filled liquid crystal cell with the easy orientation axis perpendicular to the polarization direction. The measured anchoring energy increases with illumination up to 10−4erg/cm2. Phase retardation and pretilt measurements confirmed near homogeneous alignment of the LC in a cell, while the polarization dependence of second harmonic generation suggested a near normal alignment of the adsorbed layer. We believe that light-induced rearrangement or phototransformation of the adsorbed layer causes the observed phenomenon.
Physical Review Letters
Reznikov, Yuriy; Ostroverkhova, Oksana; Singer, Kenneth D.; Kim, Jae-Hoon; Kumar, Satyendra; Lavrentovich, Oleg; Wang, Bin; West, John L (2000). Photoalignment of Liquid Crystals by Liquid Crystals. Physical Review Letters 84(9) 1930-1933. doi: 10.1103/PhysRevLett.84.1930. Retrieved from https://oaks.kent.edu/article/photoalignment-liquid-crystals-liquid-crystals