Precise placements of metal nanoparticles from reversible block copolymer nanostructures

We demonstrate the fabrication of reversible block copolymer (BCP) templates that can be used to control the spatial location of metal precursors and nanoparticles. A highly ordered polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar array was obtained by solvent annealing. Subsequent immersion of the films in a preferential solvent for the minor component block caused a reorganization of the film to generate a porous structure upon drying. When such reconstructed films were subjected to external stimuli, like solvent vapor or heat, the initial morphology was recovered. These reversible BCP templates were used to control the placement such that, subsequently, oxygen plasma treatment led to the precise placement of metal nanoparticles in a film. By controlling the concentration of the metal precursor solutions, the sizes of the nanoparticles could be tuned.