Silver Immobilization on Honeycomb-patterned Polyvinypyrrolidone thin Films via an Electroless Process

Honeycomb-patterned polyvinypyrrolidone (PVP) thin films coated with nanometer-sized silver particles were prepared using honeycomb-patterned polystyrene (PS) template films fabricated by casting a polystyrene solution under humid condition. Silver was first metallized on the patterned PS films via silver nitrate ($AgNO_3$) reduction using tetrathiafulvalene (TTF) and a small amount of PVP as the reductant and dispersing agent, respectively. The effects of $AgNO_3$, TTF, and PVP solution concentrations during the reduction process in acetonitrile were determined to obtain a uniform silver-coated honeycomb-patterned PS film. Second, the silver-metallized patterned porous PS films were filled with high PVP concentration solutions via the spincoating process. Silver-coated patterned PVP films were obtained by peeling off the PVP layer from the template PS film after drying. The results show that the honeycomb-patterned PVP films uniformly coated with silver particles are conveniently obtained using the silver-coated patterned PS template, although the direct fabrication of these films using water droplets under humid conditions was not feasible because of the water solubility of PVP.