Facile and low-cost method to fabricate a superhydrophobic aluminum alloy surface: towards optimum preparation conditions

Aluminum and the aluminum alloys are important and useful materials in industry with potential for enhanced applications via creating novel properties such as superhydrophobicity and self-cleaning features. In this study, an improved facile and low-cost surface treatment approach was developed to create a superhydrophobic aluminum surface. Overall, the modified aluminum substrates exhibited a satisfactory superhydrophobicity, with a static water contact angle of about 1461 and a contact angle hysteresis of approximately 11. The effects of two key parameters including the etching time and coating temperature were investigated using simple and handy measurement techniques. The results show that a 4 min immersion time for acid treatment of the surface and a temperature of 46 °C for the coating step would be considered optimal with respect to the contact angle and self-cleaning property. Further increasing the reaction temperature, however, leads to the cleavage of the hydrogen bonds, thus increasing the surface energy and reducing the water contact angle.