Rapid fabrication of colloidal crystal films by spin coating using polymeric particles synthesized by dispersion polymerization

Abstract

Rapid fabrication of colloidal photonic crystals was successfully carried out by spin coating using polymeric beads. To this end, monodisperse polystyrene (PS) nanospheres were synthesized by dispersion polymerization using alcohol as a reaction medium to prepare coating solution. Transmission of visible light at a specific wavelength could be observed, which is measured by transmittance spectra of coating samples. The transmission intensity of light at specific wavelength could be controlled by adjusting rotation speed or the concentration of coating solution, while peak wavelength could be adjusted by the size of PS nanospheres. Inorganic inverse opal like macroporous silica or titania films were fabricated by diffusion of silica or titania nanoparticles through colloidal crystal film, followed by calcination for removal of PS nanospheres. As a demonstrative application of inverse opal films, photocatalytic decomposition of organic dye was performed under UV light illumination by immersing the macroporous titania film in aqueous solution. The rate constant of decomposition reaction could be estimated from transient data of the dye concentration.