PA06 Tilt alignment of polyimide molecules containing azobenzene in the backbone structure induced by oblique angle irradiation of unpolarized light

Abstract

By using polarized infrared absorption spectroscopy, we have determined the average inclination angle of polyimide backbone structure in photo-aligned films. Polyimide used in this study contains azobenzene in the backbone structure. Photo-alignment treatment was performed for the corresponding polyamic acid film, using a light source of wavelength 340 〜 500 nm. The polyamic acid film (〜16 nm thick) was first irradiated at normal incidence with linearly polarized light (LP-light) of 156 J/cm^2, and then oblique angle irradiation of unpolarized light (UP-light) was performed in the plane of incidence perpendicular to the polarization direction of LP-light. We found that the average inclination angle of the polyimide backbone structure, measured from the surface plane, increases with the UP-light exposure.