Spatially Controlled Fabrication of Nanoporous Block Copolymers

A light-driven process for fabrication of spatially controlled nanoporous polymer films was demonstrated with a new diblock copolymer/small molecule additive system. Poly(α-methylstyrene- b -4-hydroxystyrene) was designed and synthesized with one block functioning as a high-resolution negative-tone photoresist and the second block being selectively removable. With a straightforward spin-coating process, a perpendicular cylindrical orientation of the removable block α-methylstyrene microdomain was induced over a wide range of film thicknesses on different substrates. Uniform nanometer-sized pores in submicron-sized photopatterns can be generated by merger of “top down” photolithographic imaging with a subsequent selective removal of a “bottom up” self-assembled nanostructure.