Ordered macroporous materials by colloidal assembly: A possible route to photonic bandgap materials

Ordered macroporous materials were produced using monodisperse polystyrene as templates. The process involved mixing the monodisperse polystyrene dispersion with a colloidal dispersion of the desired oxide. On slowly evaporating the water in the mixture, the monodisperse polystyrene particles organized themselves in an ordered lattice due to a gradual increase in their concentration. The ultrafine oxide particles packed into the voids between the polystyrene particles. In effect, a particulate gel of the oxide particles was produced around the polystyrene lattice. Subsequent removal of the polystyrene by calcination led to an ordered macroporous material with the oxide particles forming the walls of the pores.