Fabrication of superhydrophobic surfaces on zinc substrates and their application as effective corrosion barriers

Stable superhydrophobic surfaces have been effectively fabricated on the zinc substrates through one-step platinum replacement deposition process without the further modification or any other post processing procedures. The effect of reaction temperatures on the surface morphology and wettability was studied by using SEM and water contact angle (CA) analysis. Under room temperature, the composite structure formed on the zinc substrate was consisted of microscale hexagonal cavities, densely packed nanoparticles layer and micro/nanoscale structures like the flowers. The structure has exhibited great surface roughness and porosity contributing to the superhydrophobicity where the contact angle could reach an ultra high value of around 170°. Under reaction temperature of 80 °C, the composite structure, on the other hand, was hierarchical structure containing lots of nanoscale flowers and some large bushes and showed certain surface roughness (maximum CA value of about 150°). In addition, an optimal superhydrophobic platinum surface was able to provide an effective anticorrosive coating to the zinc substrate when it was immersed into an aqueous solution of sodium chloride (3% NaCl) for up to 20 days. The corrosion process was monitored through electrochemical means and the results are compared with those of unprotected zinc plates.

The SEM image of the prepared superhydrophobic surface with the novel and interesting composite structure and the highest CA value, which can be used as an effective corrosion barrier.Highlights► Effective composite structures which were only responsible for the superhydrophobicity were successfully fabricated through one-step method. ► Different interesting composite structures were prepared by changing the reaction temperature. ► The optimal superhydrophobic surface could be used as an effective corrosion barrier on the zinc substrate.