Fabrication of hierarchically structured rutile TiO2 nanorods on mica particles and their superhydrophilic coating without UV irridiation

In this work, we report a facile strategy to fabricate hierarchical rutile TiO2 thin film on mica substrates through hydrolysis of TiCl4 ethanolic solution in water. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) analysis reveal that the rutile TiO2 film is composed of nanorods and nanoparticles. The nanorod crystals grew along the [1 0 1] direction, forming predominantly exposed {1 1 0} facets. Interestingly, rutile TiO2 coated mica particles can be directly applied as a general kind of building blocks to construct large-area super hydrophilic surfaces without UV irradiation by the simple spin-coating technique. The superhydrophilicity originates from the combination of the special rough structures of hierarchical nanorods and nanoflowers and the increased hydroxyl content caused by calcinations. More importantly, this property is very stable for half a year and could be used in self-cleaning surfaces.