Template-induced fabrication of nanopatterned polymeric films by inkjet printing

Controlling the nanostructure of polymeric films using cost-effective deposition methods, like inkjet printing, has proven challenging due to the relative low resolution of such techniques. In this study, we combine inkjet printing with the use of nanopatterned substrates composed of TiO2 thin films on top of silicon wafers (NP-TiO2) for the preparation of polymeric films with similar surface morphologies. First, the evaporation induced self-assembly (EISA) process was used in the presence of a block co-polymer (polybutadiene-b-polyethyleneoxide) to prepare the NP-TiO2 substrates. The TiO2 ridges can be selectively modified with a hydrophobic perfluorinated phosphate, Zonyl FSE (ZFNP-TiO2). Conducting polymers (biotinylated polythiophene and polyaniline) were inkjet-printed both onto NP-TiO2 and ZFNP-TiO2 substrates, resulting either in continuous polymeric thin films or matrixes with separate droplets, respectively. The high surface energy determined for the NP-TiO2 substrate deemed it more suitable for the deposition of uniform and nanometer thin polymer layers. In fact, atomic force microscopy demonstrates that the deposited polymers are evenly distributed over the substrate surface while the nanopatterned structure is maintained. We conclude that the combination of inkjet printing and nanotemplating is a simple and cost-efficient way to fabricate nanopatterned polymer films with high potential in biosensing and electrical devices.