Underwater superoleophobicity of a robust rough titanium dioxide surface formed on titanium substrate by acid treatment

A robust rough titanium dioxide (TiO2) surface was prepared by acid treatment of a Ti plate and mesh. By ultraviolet (UV) irradiation, the surface exhibited superhydrophilicity and superoleophilicity in air and underwater superoleophobicity. Due to the rough surface, the underwater superoleophobicity was observed, even after dark storage for 1 week under the ambient atmosphere. The robust rough TiO2 mesh with a pore size of approximately 150 μm functioned as a high speed oil/water separation filter with high mechanical durability and self-cleaning property.