Superhydrophilic TiO2 surface without photocatalytic activation

Since the discovery of extreme surface wetting phenomenon induced by ultraviolet photocatalysis, TiO2 has become the material of choice for environmental friendly applications such as self-cleaning coatings. Nevertheless, it remains a significant challenge to realize surfaces exhibiting persistent superhydrophilicity but without the need of external stimuli. We report a bioinspired TiO2 nanostructure that shows extreme superhydrophilicity without the need of light activation, and with stability against successive wetting-dewetting cycles. This ultimate TiO2 wetting surface exhibits high transmittance from near ultraviolet to the infrared, thus enabling practical antifogging technologies where transparency is critical.