Superhydrophilic and underwater superoleophobic titania nanowires surface for oil repellency and oil/water separation

• We fabricated the titanium nanowires on Ti substrates with underwater superoleophobicity.
• The titanium nanowires films showed excellent stability in corrosive environments.
• Various oil/water mixtures can be separated using the prepared mesh with titanium nanowires.

Superhydrophilic and underwater superoleophobic titania nanowires (TNWs) films on Ti substrates were fabricated via a facile low temperature and short time-consuming route. The hierarchical one-dimension nanowires morphology with considerable roughness of the films led to the water permeation in air and oil repellency in water. Not only in pure water, the as-prepared TNWs films also exhibited excellent underwater superoleophobicity in corrosive aqueous media, including highly saline, acidic and alkaline solutions. Importantly, the surface of the TNWs films may keep the wetting properties and morphologies after immersed into corrosive solutions for 168 h, indicating the good environmental stability. The TNWs film prepared on Ti mesh showed good oil/water separation ability with a separation efficiency of high up to 99.7%. During the oil/water separation process, water passed through the mesh rapidly by gravity, while oils stayed above the mesh due to its superoleophobicity. We envision that the TNWs films with good underwater superoleophobicity may provide a candidate not only for oil/water separation but also in many other potential applications such as underwater oil manipulation, self-cleaning, bioadhesion control and fluidic devices.

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