Synthesis, characterization, and optical properties of metal-containing fluorinated polyimide films

Five kinds of metal-containing fluorinated polyimide films were prepared by thermal curing of poly(amic acid)s containing metallic salts or organometallic complexes. The chemical states, average sizes, and spatial distribution of the metallic particles were examined, and the thermal and optical properties of the films were compared with those of the colorless host polyimide. For characterizing the metal-containing polyimide films, measurements of refractive indices and wide-angle X-ray diffraction were newly applied. Copper and palladium complexes were fully or partially oxidized to form metal oxide particles, and silver complexes and gold salts were converted into metal particles after thermal imidization. All the films were much less transparent in the visible region than the host polyimide. However, the metal-containing films, except for the gold-containing film, transmitted higher than 80% at 1550 nm near-infrared. The precipitated silver and gold particles increased the average refractive indices of the polyimides.