Pressureless nanoimprinting of anatase TiO2 precursor films

A soft-imprint method for obtaining anatase TiO2 nanostructures is reported. The method is de facto pressureless and is performed without the need for dedicated imprint equipment. A titanium butoxide-based sol precursor is prepared with a heavy alcohol, methoxy ethanol, as a solvent. The use of an incompletely cross-linked very soft polydimethylsiloxane mold is found to be crucial for obtaining large-area high-quality imprints. The authors discuss quantitatively the observed substrate-constrained shrinkage of pillars and lines (ridges) during annealing.