Vapor Deposition Polymerization and Molecular Orientation of Polyimide Thin Films

Abstract

Polyimide thin films were prepared by vapor deposition polymerization. Co-deposition of pyromellitic dianhydride and 1,12-diaminododecane spontaneously yielded a thin film of polyamic acid, which was imidized by annealing in nitrogen atmosphere at 200°C. It was observed that the polyimide thin film has preferential orientation to the (001) crystal plane with the molecular chain standing on the substrate. The orientation was enhanced by matching the ratio of monomer supply for vapor deposition. The molecular orientation was also influenced by modifying the substrate surface with self-assembled monolayers (SAMs). A SAM having anhydrous carboxy terminal was effective in enhancing the molecular orientation.