Superhydrophobic TiO2 nanotube arrays with switchable adhesion in both air and oil

Superhydrophobic surfaces with smart adhesion has aroused increased interest. However, all reported surfaces can only display switchable adhesion in air. Herein, we report a fluoroalkylsilane-modified TiO 2 nanotube surface that has switchable adhesion in both air and oil as it is alternately Ultraviolet-irradiated and heated. The transition is not synchronous; a longer Ultraviolet-irradiation time is needed to obtain high adhesion in oil than in air, and the transition is more difficult in polar oil than in non-polar oil. The reversible transition attributes to the combined effect between the nanostructure and surface chemical variation, the out-of-step transition is attributed to different roles of the exposed naked TiO 2 , which offers water-adhesive force in air and oil-adhesive/water-repellent force in oil. This works reveals the effect of environmental media on surface-wetting/adhesion transition, which is helpful for design of novel adhesive surfaces to meet practical requirements.