Research on HS-WEDM and chemical etching technology of superamphiphobic surfaces on Al substrates

Superamphiphobic (both superhydrophobic and superoleophobic) surfaces on Al substrates are fabricated by the high speed wire electrical discharge machining (HS-WEDM) and chemical etching technology. The surface morphology, chemical composition and wettability of the sample surfaces are investigated using scanning electron microscopy, energy dispersive X-ray diffraction system and optical contact angle (CA) measurements. The results show that, after the HS-WEDM and chemical etching, the micrometer-scale craters and nanometer-scale acicular structures are present on the sample surfaces. The obtained sample surfaces show superamphiphobicity after fluorination. The CAs of water, ethylene glycol and peanut oil are 155.9°, 153.1° and 151.7°, respectively. The sliding angles of water, ethylene glycol and peanut oil are 2°, 3.5° and 5°, respectively. The micro/nanometer-scale rough structures and the low surface energy are essential to fabricate superamphiphobic surfaces. Compared with the other methods, the main advantages of the HS-WEDM and chemical etching technology are simple, safe, highly effective and low cost. In addition, superamphiphobic Al surfaces have potential applications in fields such as self-cleaning, oil capture, oil transportation and anti-smudge.