Molecular orientation of liquid crystal on polymer blends of coumarin and naphthalenic polyimide

Photo-induced liquid crystal alignment layers were prepared by blending polyimides and photoreactive polymers followed by polarized UV irradiation. Polyimides are selected for the purpose of improving the thermal stability of the molecular orientation of the photoreactive groups. The thermal stability of the LC alignment layer was enhanced regardless of the type of the polyimide while the direction of LC orientation was dependent on the type of polyimide. The photoreactivity of the polyimide governs the LC orientation in the blend alignment layers.