Macroporous polystyrene films obtained via colloidal crystal template

The preparation of macroporous polystyrene films with regular voids and the characterization of their diffractive optical properties are reported in this paper. These materials were synthesized using a colloidal crystal template of silica microspheres; the air between the spheres was replaced by the polystyrene; the template was removed by treatment with hydrofluoric acid. Scanning electron microscopy of these molded samples indicated highly uniform cavities ordered in hexagonal lattices, representing a negative replica of the original colloidal crystal. These large cavities are not isolated, but interconnected by a network of monodisperse smaller pores. These films exhibit striking optical properties due to the periodic arrangement of air spheres. The porous materials can be used as separation and adsorbent media, catalytic surface and supports. Furthermore, the structured porous materials can possess the desired full photonic bandgap when created out of a matrix with high refractive index.