Processing of macroporous titania thin films: from multiscale functional porosity to nanocrystalline macroporous TiO2

M.C. FUERTES; G.J.A.A. SOLER-ILLIA

CHEMISTRY OF MATERIALS

American Chemical Society

Lugar: Washington; Año: 2006 vol. 18 p. 2109 - 2117

0897-4756

Titania thin films with hierarchical pore structure (macropores and nested mesopores) were obtained in one step by a combination of sol-gel synthesis with controlled phase separation. Poly(ethylene glycol) (Mw = 2000) induces a phase separation upon film formation, producing macropores with controllable diameters between 0.1 and 2 microns. The macroporous texture can be tuned by changing the synthesis conditions and the post-treatment. The inorganic walls present mesoporosity with an interpore separation of 3-4 nm. The porous TiO2 wall surface can be modified by incorporating organic functions by postgrafting. An adequate post-synthesis treatment leads to nanocrystalline walls (anatase) without microcracks. The films thus produced can find potential applications as optical or photovoltaic materials, sensors, depollutants, and so forth.