Fabrication of inverse opal via ordered highly charged colloidal spheres

A new and simple procedure for producing highly ordered three-dimensional colloidal crystalline template was developed, which employs latexes containing highly charged polystyrene spheres. The water on the surface of the latex was evaporated, causing the formation of close-packed colloidal crystals on the surface. The driving forces for the formation of close-packed crystal involve electrostatic interaction and lateral capillary force, and the ion diffusion during the evaporation is considered to be an important factor for the successful assembly of ordered structure on the latex surface. Then the sol-gel solution was infiltrated into the interstitial space of the prepared colloidal crystals through capillary effect, and ordered inverse opals were obtained by calcining the polystyrene beads. The inverse opal thus prepared has long-range ordering with its defect-free area extending to over 10 micrometers and covering thousands of pores.