Pore size control of block copolymer-templated sol–gel-synthesized titania films deposited via spray coating

Abstract

We combine a sol–gel route with spray coating to obtain porous titania films, using the block copolymer polystyrene-block-polyethylene oxide (PS-b-PEO) as a structure-directing template of the titania nanostructures and titanium(IV) isopropoxide (TTIP) as the titania precursor. Due to the water-induced phase separation and self-assembly of PS-b-PEO and TTIP, a bicontinuous crystalline anatase titania foam structure results after a calcination step. At different sintering temperatures, ranging from 400 to 800 °C, the titania films are analyzed by X-ray diffraction to determine the crystal phase of the titania foams. This study demonstrates that the pore size of the titania foam films can be controlled by different amounts of TTIP used in the sol–gel solution and by the spray parameters of the applied spray coating. Homogenous porous films with a titania network architecture can be achieved from optimizing the number of spray shots used for the film deposition.