A simple method of preparing Ag nanoparticles coated silica colloidal crystals and polymer-Ag nanoparticles composite macroporous films

Using the Tollens-soaked sintered silica colloidal crystals as template, we developed a simple method of preparing Ag nanoparticles coated silica colloidal crystals (ANCSCC) and polymer-Ag nanoparticles composite macroporous films. In our experiment, the Ag nanoparticles are mainly distributed on the surface of the silica spheres instead of in the voids of the colloidal crystals due to the Ag (NH3)2+ ions are mainly coming from the silica microspheres. As one of the application of such composite colloidal crystals, the ANCSCC are used as the surface-enhanced Raman scattering substrates and large enhancements were observed. The ANCSCC also can be used as template to construct more complex structures of polymer-Ag nanoparticles composite macroporous films. It can be anticipated that except these samples can be used as Raman analysis and Raman image, our method introduced here will also provide a powerful platform for patterning other metal particles (such as Au or platinum) sensitized to the colloidal particles used in the colloidal crystals or preparing other novel composite structures due to its convenience and controllability.