Crystallization of colloidal crystal on hydrogel surface

A dip-coating method to fabricate wet and dry type of colloidal crystal films was developed. The wet type of colloidal crystal film was fabricated by lifting an agarose-hydrogel-coated substrate out of an aqueous suspension containing monodisperse polymer spheres and the dry type of colloidal crystal film was derived by following desiccation of the wet film. Monodisperse spheres formed ordered structures in the both type of the films, which contributed sharp reflection peaks. Brilliant colors were observed when the reflection peaks fell in the visible region. Formation mechanism of the colloidal crystal and their optical properties were discussed.