Fabrication of superhydrophobic and oleophobic surface on zinc substrate by a simple method

This paper reports a simple approach for the preparation of superhydrophobic and oleophobic surface on zinc substrate. The surface was created by chemical etching and hydrothermal reaction, consisting of micro hexagonal prisms with about 4   μm in length, 0–1   μm in gap and 0.1–0.4   μm in diameter. The surface then became superhydrophobic and oleophobic with a fluoride coating, fabricated by chemically modified with perfluorooctanoic acid anhydrous ethanol solution. The effects of different process parameters, including chemical etching time and the hydrothermal temperature, on the surface morphology and wettability were examined using a scanning electron microscope (SEM) and a contact angle tester. The optimization of process parameters were obtained, namely, the chemical etching time was 90   s and the hydrothermal temperature was 95   °C. After zinc surface was treated using the optimum parameters, the results showed that the surface exhibited repellency toward distilled water and edible peanut oil with contact angles at 151.85° and 145.62°, respectively, and the sliding angle for distilled water was less than 10°.