Controllable fabrication of stable superhydrophobic surfaces on iron substrates

Stable superhydrophobic structures were successfully prepared on iron substrates by etching in hydrochloric acid followed by zinc coating. The zinc film was electrochemically deposited on the etched iron substrate and then annealed at 180 °C. The morphology and chemical composition of the prepared surfaces were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscope (AFM), energy-dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). The wetting properties of the surfaces upon each processing step were evaluated using water contact angle (WCA) measurements. At the optimal condition, the surface displayed a superhydrophobic character with a WCA of about 163 ± 2° and a low sliding angle of about 0 ± 2°. The experimental conditions, such as electrolyte concentration, electroplating time, annealing condition, and etching time were investigated to determine their effects on the superhydrophobicity. It was also demonstrated that the as-prepared superhydrophobic surfaces exhibited anti-corrosion properties and a long-term stability. The freezing properties of the superhydrophobic surfaces were also investigated.