Preparation and assembly performance of colloidal particles of photonic crystals with controlled photonic band gaps

Monodisperse microspheres with average particle size in the range of 100-600 nm, whose main monomer was styrene, were prepared by soap-free emulsion polymerization. The factors influencing polymer colloidal particle sizes and size distributions were investigated, including initiator concentration, polymerization temperature and hydrophilic monomer amount. Then, six kinds of polymer microspheres with average size from 153 nm to 565 nm were selected to grow colloid photonic crystal by vertical deposition method. Results showed that photonic band gaps could be effectively adjusted by changing the particle size. The obtained photonic crystals were highly ordered face-centered cubic structures. Furthermore, vertical deposition was only suitable for particles with average size less than 300 nm.