Robust technique allowing the manufacture of superoleophobic (omniphobic) metallic surfaces

Omniphobic metallic surfaces obtained with a robust two-stage process are reported. The surfaces demonstrate high apparent contact angles accompanied with a low contact angle hysteresis for a variety of liquids, including water, diidomethane, canola, castor, silicone oils, and crude petroleum oil. The superoleophobicity was achieved by fluorination of the nano-rough aluminum surfaces under treatment with perfluorononanoic acid, as established by TOF-SIMS spectrometry. The stability of the Cassie wetting regime was investigated. The critical surface tension of a liquid corresponding to the onset of wetting transitions was established experimentally.