| Nanomaterials with spatially ordered stucture have current and future potential applications in optical information processing and storage, advanced coatings, catalysis, and other emerging nanotechnologies. Photonic crystals is a promising class of such materials formed by different refractive index (dielectric constant) materials, periodically arranging to form long-range order structure in the space. This long-range ordering of photonic crystal results in a number of distinctive characteristics such as optical diffraction photonic localization and photonic bandgaps. So compared with the traditional film and block materials, photonic crystal has potential application in the display device, photoelectric device, and the sensing device. In many applications, the structural color has attracted considerable attention due to its energy conservation.In this paper, polystyrene (PS) microspheres, PS@TiO2 core-shell microspheres, TiO2 hollow semi-spheres and TiO2/C hollow microspheres were prepared, structural color films were prepared on glass by self-assembly. The samples were characterized by XRD?SEM?TEM?FUR?Raman spectra?TG to research the formative factors of microspheres and the influence factors of structural color films, in order to prepare highly saturated and high brightness structural films.(1) The monodispersed PS nanospheres were prepared by free-soap emulsion polymerization, and then spheres were self-assembled by vertical deposition method on glass to obtain PS structural color films. During the experiments, the factors which affect the PS particle size and the influences of post-treating temperature to the films were explored. The results showed that good monodispersed PS nanospheres whose surfaces were smooth and clean could be obtained by free-soap emulsion polymerization. The particle sizes could be limited well from 150 to 400 nm by controlling the amount of st, MAA, Kps. With the increase of the amount of st, the size of PS spheres increased; while when the amount of MAA added, the particle size decreased; with the increase of the amount of Kps, the size of PS spheres increased first and then decreased. The analysis of films showed that when the particle sizes increased from 177 nm to 335 nm, the peak of reflectance spectrum moved to long-wave band and the structural color redshifted, from 389 nm to 646 nm; with the increase of post-treating temperature, the gap between every PS sphere decreased and the brightness of films reduced gradually until the color faded away when the temperature reached 110 ?.(2) The PS@TiO2 core-shell spheres were prepared by Silane coupling agent, and then self-assembled by vertical deposition method. In order to gain good structural films, the surface of the core-shell spheres was improved by changing reaction condition. The results showed that the TiO2 shell was covered PS spheres successfully and the thickness of the shell could be adjusted by changing the mass ratio of PS/TBOT and the reacting time. But the shell was nonuniform and uncontrollable. What is more, the TiO2 particles aggregated easily. Compared with the PS structural color, the structural color of PS@TiO2 core-shell spheres red shifted from blue to reddish. But the brightness and saturation were poor and spheres were easily subsided in the process of preparation.(3) The PS@TiO2 core-shell spheres were prepared by mixed solvent method, and then self-assembled by vertical deposition method. The influences of the react factors to the particle sizes and the properties of surface were studied, and the influences of the particle sizes to the films were researched too. The results showed that uniform PS@TiO2 core-shell spheres could be obtained by this method; Coating time had little influence to PS@TiO2 core-shell spheres; when the amount of NH3H2O increased, the particles on the spheres surface increased, resulting in the reduce of smoothness, The amount of NH3H2O should be controlled from 0.25 to 0.5 mL; With the increase of acetonitrile, the smoothness of core-shell spheres roughened first, then became smooth and finally turned rough. The smooth, homogeneous titania coatings could be achieved; when the volume ratio was 3:1; when the amount of TBOT increased, the sizes of core-shell spheres increased, while too much TBOT resulted in the increase of free TiO2 particles; compared with the pure PS structural color films, the structural color of PS@TiO2 redshifted obviously.(4) The PS@TiO2 core-shell spheres prepared above were calcined for 3 h in 500 ? air furnace and atmosphere furnace respectively to obtain TiO2 hollow semi-spheres and TiO2/C hollow microspheres. The results showed that TiO2 hollow semi-spheres were severely damaged, the structure of TiO2/C composite microspheres was relatively complete. In the process of degrading RB, the photocatalytic performance of TiO2 hollow semi-spheres was better than that of P25 and TiO2 powders. When the content of TBOT increased from 0.5 mL to 1 mL, the degradation efficiency of RB was improved; semi-spheres can improve the photocatalytic performance of TiO2. To TiO2/C hollow microspheres, when the content of TBOT was 1 mL, the thickness of TiO2 shell was optimum, the photocatalytic performance was the best. |
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