Superhydrophilic Ag-TiO2 thin films were prepared by the sol-gel method using titanium-n-butoxide as TiO2 precursor

silver nitrate as silver source

poly(ethylene glycol) (PEG2000) as structure directing agent. As-prepared composite thin films were characterized by X-ray diffraction

X-ray photoelectronic spectroscopy

scanning electron microscopy and atom force microscopy. The superhydrophilicity of Ag-TiO2 thin films with different Ag and PEG2000 contents were evaluated in terms of static water contact angle

wetting time and long-term stability. Ag-doping significantly improved response to visible light and shortened wetting time

and porous surface with high roughness favored long-term superhydrophilicity. The Ag-TiO2 thin films with 10% Ag doping and 5% PEG2000 content showed excellent superhydrophilic properties under natural light conditions. Water droplets could fully spread on the surface within 0.2 second with static water contact angle of 0°. Superhydrophilicity was maintained for more than 30 d when the thin films were stored in dark place. Superhydrophilic properties were enhanced when the films were irradiated under visible light. The composite Ag-TiO2 thin films showed excellent anti-fogging effect.