Anti-bacterial, icephobic, and corrosion protection potentials of superhydrophobic nanodiamond composite coating

Superhydrophobic nanocomposite coating was designed using nanodiamonds (NDs) and siloxane-acrylic resins via the spray coating process. The NDs coating showed a high-water contact angle of 154° and a very low sliding angle of 6°. After 10 cycles of icing and de-icing, the coating exhibited a delay in ice formation time and reduced ice adhesion strength (~ 44.56 kPa) in comparison with the bare metal (~ 77 kPa). The superhydrophobic nanocomposite coating offers excellent anti-bacterial adhesion properties; revealing a 73% decrease of Escherichia coli (E. coli) bacterial colony on the superhydrophobic NDs coated sample compared to the blank sample after 24 h of incubation. The electrochemical impedance spectroscope measurement reveals an impedance value of 106 Ω cm2 at 4 h of immersion, signifying that the coating exhibited corrosion protection ability at the initial hours of immersion. This protective property is comparable good for a very thin coating of 10 µm thickness. Besides, there was a minimal detachment of the coating from the substrate during the cross-cut adhesion test, and no sign of crack after the impact test indicating a good surface adhesion property.