Efficient fabrication of large, robust films of 3D-ordered polystyrene latex

Two novel techniques were developed to fabricate robust, low-defect films of 3D-ordered polystyrene latices with titania shell. One is sonication-assisted casting that was used to prepare highly ordered three dimensional (3D) latex films of centimeter sizes front aqueous polystyrene microspheres of different diameters (202-1053 nm). The thickness of the 3D-ordered latex film was adjustable from several layers to several tens of layers by changing the concentration of the latex solution. The films showed photonic stop bands according to the sphere size in the as-prepared 3D-ordered latex film. The other novel technique - gas-phase surface sol-gel process (G-SSG) - was employed to coat the surface of the spheres with run-thick titania layer without dipping. This procedure glued the spheres together to give mechanically more robust films without changing its morphology. These 3D-ordered latex films, both as-prepared and titania coated, displayed photonic stop bands that are consistent with theoretical estimates based on the latex size. (c) 2005 Elsevier B.V. All rights reserved.