A fast method to fabricate superhydrophobic surfaces on zinc substrate with ion assisted chemical etching

Abstract A metal assisted chemical etching process was proposed to rapidly fabricate super-hydrophobic surfaces on Zn substrates. The influence of three assisting metal ions (Ag + , Cu 2+ , Cr 3+ ) on the morphology of the fabricated surfaces, and their hydrophobicity after modification by fluorosilane, were studied. This work indicates that the metal ions play an important role on the structure and the hydrophobicity of the prepared surfaces. The rough structure required for super-hydrophobic surfaces, with contact angles of 158 ± 2° and 161 ± 2°, respectively, can be easily obtained within 5 s with Cu 2+ or Ag + assisted chemical etching process. The treatment conditions of Cu 2+ assisted chemical etching method were optimized. The sample with the highest contact angle can be achieved when the concentration of Cu(NO 3 ) 2 is 0.08 mol L −1 , the concentration of HNO 3 is 0.6 mol L −1 , and the etching time is 5 s at 30 °C. And the prepared superhydrophobic surfaces exhibited enough stability in the air.