Porous polymer films with size-tunable surface pores

A novel method was developed to produce a porous polymer film with size-tunable pores on its surface. The porous film was produced using polystyrene microspheres as a template and the surface pore size can be tuned without changing the size of the template microsphere. Polystyrene microspheres were self-assembled on a substrate precoated with a thin layer of polystyrene and heated at an appropriate temperature, prior to infusion of a polymer precursor solution into cavities of the template microspheres, solidification of the polymer, and removal of the microspheres. The surface pore sizes can be tuned by changing the temperature and time for the heat treatment. With use of this method, porous films with nanosized surface pores can be produced using microsized spheres as the template, which can find applications in many areas.