A facial approach to fabricate superhydrophobic aluminum surface

A facial chemical etching method was developed for fabricating superhydrophobic aluminum surfaces. The resultant surfaces were characterized by scanning electron microscopy, water contact angle (WCA) measurement, and optical methods. The surfaces of the modified aluminum substrates exhibit superhydrophobicity, with a WCA of 154.8 degrees +/- 1.6 degrees and a water sliding angle of about 5 degrees. The etched surfaces have binary structure consisting of the irregular microscale plateaus and caves in which there are the nanoscale block-like convexes and hollows. The superhydrophobicity of aluminum substrates occurs only in some structures in which the plateaus and caves are appropriately ordered. The resulted surfaces have good self-cleaning properties. The results demonstrate that it is possible to construct superhydrophobic surface on hydrophilic substrates by tailoring the surface structure to providing more spaces to trap air. Copyright (c) 2009 John Wiley & Sons, Ltd.