Tailoring the wettability of nanocrystalline TiO2 films

The water contact angle (WCA) of nanocrystalline TiO2 films was adjusted by fluoroalkylsilane (FAS) modification and photocatalytic lithography. FAS modification made the surface hydrophobic with the WCA up to ∼156°, while ultraviolet (UV) irradiation changed surface to hydrophilic with the WCA down to ∼0°. Both the hydrophobicity and hydrophilicity were enhanced by surface roughness. The wettability can be tailored by varying the concentration of FAS solution and soaking time, as well as the UV light intensity and irradiation time. Additionally, with the help of photomasks, hydrophobic-hydrophilic micropatterns can be fabricated and manifested via area-selective deposition of polystyrene particles.

► The nanocrystalline TiO2 based surface with controllable wettability was discussed. ► The fine surface TiO2 films improved the hydrophobic and hydrophilic properties. ► The surface wettability can be easily tuned. ► The hydrophobic-hydrophilic patterns were used to area-selectively grow PS particles.