Experimental Details - Microstructured Silica
Latex particles used: Monodisperse suspensions of amidine (positively charged) or sulfate (negatively charged) latexes.
Crystal assembly: The diluted latex particles are assembled into a colloidal crystal by slow filtration through a smooth membrane with narrow pores (100 nm).
Functionalization: The latex layer was washed with HTAB solution for 20 min. The excess unadsorbed surfactant was removed by a quick (< 60 s) wash with deionized water. The HTAB adsorption step provides the functionalized surface at which the silica polymerization is induced. If this step is omitted, the material collapses on calcination.
Silica polymerization: A 1 M Si(OH)4 aqueous solution was diluted 2´
with water before addition to the colloidal crystal films.
Calcination: In a programmable furnace for 4 h at 450oC with an initial temperature ramp of 1oC/min.
Characterization: Optical microscopy, SEM and TGA analysis.
© Copyright O. D. Velev 1998