Surface morphology effects on the light-controlled wettability of ZnO nanostructures

► As-grown ZnO nanostructures are highly hydrophobic: CA is in range 90-127°. ► UV irradiation of ZnO nanostructures causes the change of their wettability character. ► Contrast and time of wettability change depend on the ZnO surface morphology. ► Both micro- and nano-roughness enhance the current wettability character. ► Complex structures (micro + nano rough) have the most outstanding wettability properties.