Fabrication of macroporous titanium dioxide film using PMMA microspheres as template
A novel synthetic procedure is described for the fabrication of macroporous titanium dioxide (TiO2) films with an ordered, uniform pore framework comprised of nanocrystalline anatase mainly. The synthetic approach involved several processes. First, polymethyl methacrylate (PMMA) microspheres (87 nm) were synthesized by using a dispersion polymerization technique in the presence of Fenton reagent (FeSO4/H2O2) as a novel initiator, which has advantages such as simple and fast polymerization process without deoxygenation. Next, the templates of PMMA microspheres were assembled on clean substrates by dip-drawing technique. Finally, the macroporous TiO2 films with the average size of pores about 87 nm were obtained by sol-dipping template method and calcination to remove the templates at 550 °C. The test results of X-ray diffraction indicate that the nanocrystalline of anatase formed after calcination. The mechanisms of PMMA polymerization and template formation were proposed. Furthermore, both structures and morphologies of the composite films were investigated with field emission scanning electron microscope, and the processes of the thermal decomposition of PMMA and TiO2 gel were also discussed with thermo gravimetric analysis. This ordered and uniform pore framework could be used as the promising ultrafilter membranes showing active photocatalysis without intensive fouling.