Synthesis, Characterization, and Optical Properties of Metal-Containing Fluorinated Polyimide Films

Abstract

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.

Synthesis, Characterization, and Optical Properties of Uniaxially Drawn and Gold Nanoparticle Dispersed Fluorinated Polyimide Films.

“…In contrast, the transparency of Au-dispersed polyimide films cured on Si02 substrates was less than 10% in the MR region, which is due to the significant growth of Au-crystallites on the substrate-side surface. [3] This indicates that the films prepared in this study can be used as thin and flexible visible-cut/NW-pass optical filters. Fig.…”

“…3 and 4 indicates that most of the particles have pressed octahedron and rectangular parallelepiped structures of the crystallites. In an Au-dispersed film formed on Si02 substrate, particles having rectangular shapes were observed [3], but no lozenge-shaped particles were observed. Micrographs of a film prepared in air are basically the same as Figs.…”

“…A similar phenomenon was observed for unoriented Au-dispersed film. [3] In addition, broad diffraction peaks (not shown) are observed at 16.1° and 24.2°, which are assigned to the lateral order of uniaxially oriented polyimide chains and amorphous halo, respectively. [ 11 ] Figs.3 and 4 show the cross sectional TEM micrographs of a film prepared under nitrogen.…”

“…[3] For investigation of the effect of the final curing temperature, polyimides were needed whose optical properties are stable over 300°C. The fluorinated polyimides developed by the authors show almost no color and their transmittance and refractive indices are stable even after curing at 380°C.…”

“…An anisotropy in optical transmittance of more than 300 (25 dB) was obtained for a 15 µm-thick film at 850 nm, and the optical loss for the transmitting polarization including surface reflection is less than 1.3 dB. [6] The optical and mechanical properties were retained after annealing at 150°C for 1 h. Nanometer-sized metal particles are known to have inter-esting optical functions such as the characteristic coloration [3] and optical non-linearity. [7] We report here the thermogravimetric analysis, x-ray diffraction patterns, transmission electron micrographs, FT IR analysis of polymer orientations, and optical and thermal properties of uniaxially drawn and gold nanoparticle dispersed fluorinated polyimide films.…”