Nonlinear optical spectroscopy for surface studies of rubbed polyimide

Summary form only given. In fabrication of liquid-crystal (LC) display devices, rubbed polyimide films on glass substrates are widely used to align bulk liquid crystal molecules in a preferred direction. It is believed that rubbing induces anisotropic chain orientation on the polymer surfaces, and the subsequent LC-polymer interaction leads to the bulk LC alignment, but the detailed surface structure of the rubbed polyimide is not known. Polarized Fourier transform infrared (FTIR) measurements have shown that rubbing indeed induces anisotropy in the IR absorption of the polyimide film