Fabrication of polystyrene colloidal crystals

In this paper, we have successfully fabricated the colloidal crystals of mo nodispersed polystyrene latex. Styrene was polymerized in degassed water at 75 degreesC, using potassium persulfate as an initiator. The surfactant wa s sodium dodecyl sulfate(SDS). Firstly, the monodispersed polystyrene latex with an average diameter of some nanometers was synthesized via emulsion p olymerization, then these small latex particles were used to act as seeds f or further growth. The size of polystyrene latex was controlled between 50 nm and 400 nm via diversifying the condition of polymerization. The resulte d emulsion solution could accumulate slowly to form three-dimensional order ed structure, which was induced by capillary as the solvent evaporating at room temperature. The opal is close-packed face center cubic (f. c. c) latt ice of polystyrene latex. Defects such as vacancies, dislocations or grain boundaries could be obviously observed from the SEM images. Reflectance spe ctra showed the red shift of specular reflectivity peak for the polystyrene colloidal crystal as the size of polystyrene latex increasing. It was demo nstrated that the reflectance is intrinsic property of these colloidal crys tals. This provides ideal model for the research and application of photoni c crystals and form useful template for growth of various ordered macroporo us materials.