Superhydrophobic surfaces on diverse metals based on ultrafast sequential deposition of silver and stearic acid

Abstract

In the presence of NaF, silver (Ag) was galvanically deposited onto aluminum (Al) substrate quickly (typically 10s) from dilute aqueous AgNO3 solution. Subsequent immersion into ethanolic solution of stearic acid (SA, for 30s) rendered Al superhydrophobic. The deposition and morphological evolution of Ag were investigated in detail. It was found that NaF was indispensable to initiate the Ag galvanic deposition by dissolving the barrier oxide layer. Moreover, as reaction time prolonging, surface morphology and surface wettability varied synchronously. This strategy to fabricate superhydrophobic surface (coded as SHS) was also applicable to many other metals, such as Fe, Co and Mo with oxide passivation layer (NaF was needed) or Mg, Zn, Sn, Pb, and Cu with no apparent oxide passivation layer (NaF was not needed). In summary, the strategy to fabricate SHS based on Ag deposition and SA modification was quite impressive for its time-saving benefits and wide substrate applicability.