Preparation Of Three-Dimensional Colloidal Crystal And Ordered Macroporous Materials

Three-dimensional ordered macroporous （3DOM） materials, compared withtraditional macroporous materials, not only have the large surface area and high porosity,but also have a series of self-characters, such as periodic pore structure and uniform poresize which can be adjusted easily. In the field of catalyst、carrier、photonic crystals and soon, have wide application prospects.In this paper, monodisperse polystyrene（PS）of189-1680nm in diameter weresynthesized by using a modified emulsifier-free emulsion polymerization method. Fieldemission scanning electron microscopy （FSEM） was used to characterized the PSsphere. We found that with the increased of the use of monomer, the obtained PS particlesize would increase; With the increased use of initiator、PVP and reaction temperature,the obtained PS particle size would decrease; With the increased of the reaction time, theobtained PS particle size did not change significantly; The amount of PVP is a majorfactor to decide the PS spheres size.The prepared PS spheres were assembly to colloidal crystals by using the method ofvertical deposition. The colloidal crystal displayed different colors with the difference ofparticle size. These phenomenons were the the result of Bragg diffraction. We used theFSEM and UV-Vis spectrophotometer （UV） to characterize the colloidal crystal.Discusses the colloid concentration, evaporation temperature, sintering and solventeffects on colloidal crystals. Based on these discussion，we used the simple multiplevertical deposition, prepared the heterogeneous structure of PS colloidal crystals.We used a dip-draw-clean method to fill the colloidal crystal template with the golof tetrabutyl titanate and tetraethoxysilane. And prepared the3DOM TiO₂and SiO₂materials successfully. We used FSEM to observe samples, found the3DOM TiO₂material surface is not covered and very smooth, big bore holes arranged intoface-centred cubic structure（fcc）, fewer defects, no collapse, and small windows connected with the macropores. The prepared3DOM TiO₂hole shrinkage rate was only11.9%in calculation. XRD was used to characterize the3DOM TiO₂thin films，andfound that after550℃calcined, the obtained3DOM TiO₂film was anatase structure.TEM images showed that the obtained3DOM TiO₂thin films were Composed by about10nm of TiO₂nano particles. SEM image showed that after ethanol washed two times,the obtained3DOM SiO₂with small windows connected with the macropores and bigbore holes arranged into fcc structure. The hole shrinkage rate was10.4%. It is the firsttime that we used such a simple yet highly efficient method to fabricate high-quality3DOM oxide materials. It has a good practical value.