Optimization of emulsion polymerization of self-assembled colloidal crystals

Nano-sized Polymeric colloidal particles could be self-organized into three dimensional structures to obtain desired optical properties. In this research, a facile emulsifier-free emulsion polymerization method was used to synthesize highly mono-disperse sub-micron polystyrene colloids. By controlling of the reaction parameters, various sizes of colloidal particles were prepared in the range of 190 nm up to 400 nm. The colloidal particles were used to prepare a uniform colloidal crystal (CC) films. These CC films showed bright colors and a characteristic reflection bands according to the size of colloidal particles (photonic band gap). For further studies, the Bragg reflection of the CC films was evaluated to overlap with the wavelength of the light emitting of a fluorescent dye.