Fabrication and structural characterization of nanocomposites consisting of Ni nanoparticles dispersed in polyimide films

Formation and structure of composite layer consisting ofpolyimide films containing Ni nanoparticles were investigated.The preparation method relies on KOH treatment on polyimide filmto form carboxyl acid groups and adsorption of Ni ions by ionexchange followed by hydrogen reduction. The amount of Ni ionsadsorbed in polyimide films were found to be systematicallycontrolled by changing initial KOH concentration, subsequent ionexchange time, pH and temperature. Cross-sectional TEMobservation revealed that Ni nanoparticles with 3-5 nm indiameter were homogeneously dispersed in the surface modifiedpolyimide layer after heat treatment above 250 ^°C in H₂atmosphere. The size and distribution of the Ni nanoparticleswere strongly dependent on the heat treatment temperature,indicating that this method allows microstructural tuning ofmetal/polymer nanocomposites.