Engineering a Titanium Surface with Controllable Oleophobicity and Switchable Oil Adhesion

We demonstrate techniques to fabricate, for the first time, superoleophobic surfaces on engineered functional titanium either by novel anodization or by a combination of anodization and laser technology. The approach basically involves the formation of microstructures on a Ti surface first and then the formation of TiO2 nanotube arrays above, followed by postmodification of hydrophobic materials. Of particular interest is that the switchable wettability toward superoleophobicity and the reversible adhesion of oil droplets between sliding superoleophobicity and sticky superoleophobicity were realized on these surfaces through the alternate treatment by UV and annealing. The movement of a magnetic oil droplet can be manipulated on the surface by applying an external magnetic field. The applications of the engineered surfaces in oil sealing and anticreeping are demonstrated. The approach represents a key addition to functional superoleophobic materials.