Photo-alignment Properties of Main-Chain Liquid-Crystalline Polyimides Containing Chalcone Derivative

We investigated photo-alignment properties of main-chain polyimides prepared from acid anhydrides [4,4′-(hexafluoro-isopropylidene) diphthalic anhydride (6FDA) or 4,4′-biphthalic anhydride (BPDA)] and diamine derivatives containing a chalcone group. The polyimides in the film state were irradiated with linearly polarized UV (LPUV) light under different conditions. The liquid-crystalline (LC) cell was fabricated from the polyimide film irradiated with LPUV light. A mixture of a low molecular liquid crystal (4-cyano-4′-n-pentylbiphenyl: 5CB) and a dichroic dye was filled in the LC cell. 5CB in the LC cell was easily aligned perpendicular to the electric vector of the incident LPUV light.