Abstract: Superamphiphobic (both superhydrophobic and superoleophobic) surfaces on Al substrates are fabricated via electrochemical and chemical machining technology. The surface morphology, chemical composition, and wettability of the sample surfaces are investigated using scanning electron microscopy, X-ray diffraction, energy-dispersive spectroscopy, and optical contact angle measurements. The results show that, after the electrochemical and chemical machining, the micro/nanometer-scale binary rough structures composed of micrometer-scale rectangular-shaped plateau structures and nanometer-scale needle-like boehmite and alumina structures are present on the sample surfaces. The obtained sample surfaces show superhydrophilicity and superoleophilicity before fluorination. Whereas, after fluorination, the sample surfaces change to superamphiphobic. The water contact angles of water, glycerol, peanut oil, and hexadecane are 166.6°, 164.7°, 160.1°, and 157.7°, respectively. The water rolling angles of water, glycerol, peanut oil, and hexadecane are 2°, 2°, 4°, and 3.5°, respectively. The acquirement of the micro/nanometer-scale rough structures and the reduction of the surface energy are essential to fabricate superamphiphobic surfaces. Compared with the other methods, the main advantages of the electrochemical and chemical machining technology are simple, highly effective, safe, and low cost.

Key words: Chemical machining, Electrochemical machining, Superhydrophobic, Superolephobic