We demonstrate a simple, rapid, cost-effective and robust approach to modify the surface of a solid substrate, based on a UV-irradiated film of a general plastic polymer. Thin films of homopolymer polystyrene (PS) of controlled thickness were spin-coated on diverse metal, semiconductor and polymeric surfaces. Specific surface chemistry was tuned with UV irradiation in air (UVIA); interactions at the PS/substrate interface were enhanced with UV irradiation in nitrogen (UVIN). Oxidized and cross-linked PS served as a neutral surface on various metal, quartz, semiconductor and polymeric substrates to induce perpendicularly oriented cylinders or lamellae in a self-assembled block copolymer.