Preparation of Superoleophobic and Superhydrophobic Titanium Surfaces via an Environmentally Friendly Electrochemical Etching Method

The preparation of superoleophobic and superhydrophobic surfaces requires surface microgeometries and surface chemistry. In this study, an economical and environmentally friendly electrochemical etching method was developed to prepare superoleophobic and superhydrophobic titanium surfaces. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FTIR), energy-dispersive spectroscopy (EDS), and optical contact angle measurements were used to characterize the surface morphologies, crystal structures, chemical compositions, and wettability of the surfaces for both water and oil. The results show that the prepared superoleophobic surface has water, glycerol, and hexadecane contact angles above 150°, with rolling angles of only 1–2°. Analysis of the electrolyte, the reaction process, and the products demonstrates that the proposed method is inexpensive and environmentally friendly. The effects of electrochemical parameters such as current density, electrochemical etching time, electrolyte temperature, and electrolyte concentration on the surface wettability for water, glycerol, and hexadecane were also investigated. Superoleophobicity and superhydrophobicity can be selectively obtained by varying the electrochemical parameters. The proposed method is believed to be adopted for industrial production of superoleophobic and superhydrophobic titanium surfaces.