In situ fabrication of flower-like ZnO on aluminum alloy surface with superhydrophobicity

A hierarchical structure ZnO is fabricated on aluminum alloy substrate by hydrothermal method at low temperature of 90 degrees C, following treated by the solution of PDMS to achieve superhydrophobicity. We investigate the effect of PDMS concentrations on surface hydrophobicity. Results are shown that the optimum superhydrophobic surface (Al-ZnO-PDMS8) possesses a water contact angle as high as 161.1 degrees and a low water sliding angle of 3.3 degrees. The chemical compositions and surface morphologies are investigated using FTIR, XPS, EDS, FESEM, and AFM. The delayed-icing time of 7 mu L water droplets on Al-ZnO-PDMS8 at 15 degrees C is 5.46 times longer than that of the bare aluminum alloy surfaces. Furthermore, the influence of temperature and droplet volume on delayed-icing time is measured and analyzed. Also, the superhydrophobic surface displays excellent anti-frost performance with decreased icing weight and area. Meanwhile, the superhydrophobic surface shows good self-cleaning performance by different types of daily water-based pollutions. The behavior of impacting water droplet is researched by using highspeed photography, indicating that pollutants were difficult to adhere to the surfaces, which could be easily cleaned up by rolling water droplets. These investigations are believed that there is an extent promotion to practical applications of superhydrophobic surface, especially in the fields of anti-icing and self-cleaning.