Surface chemical analysis of photocatalytic wettability conversion of TiO2 nanoparticle coating

► Mechanism behind wettability conversion of TiO2 nanoparticle coating was analyzed. ► Initially superhydrophobic TiO2 surface turns to hydrophilic by UVA irradiation. ► Oven treatment convert TiO2 nanocoated hydrophilic surface back to superhydrophobic. ► XPS shows changes in the surface chemistry before, and after treatments. ► Wettability changes are related to hydroxyl groups/aliphatic chains on the surface.