Fabrication of metallic nanoparticle mono-layer made from selective reaction of Ni100−xFex thin films with polyamic acid during its imidization

A mono-layer of metallic Ni nanoparticles with different average particle sizes was prepared on top of a polyimide film by depositing a Ni100−xFex alloy thin film on the polyimide precursor. During imidization of the precursor, Fe was selectively etched from the alloy film, leaving behind Ni-enriched nanoparticles. Average particle size of the thus-produced nanoparticles ranged from 5 to 7 nm depending on the Fe content in the initial metal film and increasing Fe content also resulted in formation of spinel NiFe2O4 particles intermixed with the Ni particles. Because these particles are located at the very top of the polyimide film, it was demonstrated that the nanoparticles can be used as a template for building functional nanostructures.