The superhydrophobic aluminum surface prepared by different methods

• Superhydrophobicity was obtained on aluminum alloy surface by different methods.
• The irregular porous surfaces structures were similar to lotus leaf surfaces.
• The stearic acid–ethanol coating was used to modify the irregular porous surfaces.
• The best superhydrophobicity was the surface prepared by acid etching method.
• The method is facile, the materials is inexpensive and is expected to be used widely.

Inspired by the biomimic lotus leaves, superhydrophobic aluminum alloy surfaces (SAAS) with modified nano-/micro-structures were prepared by different methods. Their surface morphology and hydrophobic properties were studied by using scanning electron microscopy (SEM) and contact angle meter, respectively. The results demonstrate the superhydrophobic surfaces irregular porous structures were successfully fabricated. Similar to lotus leaf surfaces, the depth and width of corrosion pits were in the range of 5–30 µm and 5–20 µm, respectively. The total thickness of the films was in the range of 5–30 μm. The water contact angles (WCAs) were larger than 150° and the water sliding angles (WSAs) were lower than 10°. The best superhydrophobicity was obtained by acid etching method, the stearic acid–ethanol coating was used to modify the irregular porous surfaces, with the average WCAs and WSAs of 166±1.8° and 7°, respectively. The method is facile, the materials is inexpensive and is expected to be used widely.