One-Pot Route to Produce Hierarchically Porous Titania Thin Films by Controlled Self-Assembly, Swelling, and Phase Separation

Abstract

Expanding mesopore size beyond a 10 nm diameter is a big challenge for developing applications based on mesostructured-mesoporous thin films, especially in nanobiotechnology. This triggers the need of new multipore materials produced by reproducible soft chemistry routes. We present here a novel and simple one-pot synthesis method that allows the creation of a new kind of hierarchically porous thin film using a combination of supramolecular templating and phase separation. Accurate tuning of pore size distribution (bimodal, with small mesopores 13-18 nm diameter, and large pores 20-150 nm diameter) is attained by controlling the solubility of a pore enhancement agent, poly (propylene glycol), in the presence of a co-solvent. The reported strategy permits the in situ tuning of the processes that govern the pore generation at different length scales; this opens a path for fabrication of multimodal mesoporous films, which represents an important breakthrough in the field.