Facile fabrication of a robust and corrosion resistant superhydrophobic aluminum alloy surface by a novel method

This work reports a novel method involving anodic oxidation and a self-assembly process for controllable fabrication of a robust superhydrophobic aluminum (Al) alloy surface. The superhydrophobic surface with a water contact angle of 157.5 +/- 0.5 degrees and a sliding angle of 3 +/- 0.7 degrees is derived from its hierarchical micro-nanostructure and the assembly of low surface energy fluorinated components on it. Furthermore, the transformation from superhydrophilicity to superhydrophobicity can be achieved by adjusting the modification process for the constructed surface. The anti-scratch tests show that the superhydrophobic surface has good mechanical stability. It maintains superhydrophobicity after mechanical abrasion against P400 grit SiC sandpaper for 0.4 m and P800 grit sandpaper for 0.8 m, at the applied pressure of 3.60 kPa. The potentiodynamic polarization and electrochemical impedance spectroscopy tests show that the as-prepared superhydrophobic surface has excellent corrosion resistance. In addition, the as-prepared superhydrophobic surface has self-cleaning ability and good long-term stability. It is believed that the facile fabrication process offers an effective and promising application for fabricating a robust, anticorrosive and large scale superhydrophobic Al alloy surface.