Surface hydrogenation reaction was perfomed to distinguish the mechanism of the photoalignment using poly(vinyl cinnamate)(PVCi). The reaction makes it possible to remove any plausible surface ordering of cinnamate side groups which may happen during the photoalignment process while the generated photoproducts are still intact. After considering the alignment and the azimuthal anchoring energy of the hydrogenated PVCi/E7 cells, it was identified that the alignment of LC molecules is mainly induced by the photoproducts.
