Photo-induced liquid crystal alignment of poly(vinyl cinnamate) and fluorinated polyimide blends

Liquid crystal(LC) alignment properties were mainly affected by surface properties of alignment layers. In our previous work, we prepared poly(vinyl cinnamate) (PVCi) and polyimide blend alignment layer for thermally stable LC alignment. In this work, we utilized fluorinated polyimide for blend alignment layers in order to modify surface properties of alignment layers. For this purpose, polyimides containing fluorine unit were synthesized and used for the blend alignment layers. Fluorine containing diamine, 4,4′-bis[2-(4-aminophenyl)hexafluoropropyl]-diphenyl ether(BDAF), is used for the polyimide synthesis. We prepared the fluorinated polyimide and PVCi blend alignment layers and investigated the effect of fluorine on the LC alignment properties and pretilt angle of LC.