Bioinspired superhydrophobic and oil-infused nanostructured surface for Cu corrosion inhibition: A comparison study

Abstract

Inspired by the lotus leaf and pitcher plant, superhydrophobic surface (SHP) and oil-infused surface (OIS) have spurred wide interest in material protection field. However, which is the better choice for corrosion inhibition still remains to reveal. Herein, we report a scalable route to build superhydrophobicity and OIS onto representative Cu substrate. The as-prepared surfaces have been used for corrosion inhibition in natural seawater environment. For superhydrophobicity and OIS, the air and oil cushion anchored in Cu(OH)2 nano-needle matrix can both behave as the barrier to hurdle the diffusion of corrosive species in water phase. Using different electrochemical approaches including scanning Kelvin probe (SKP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization, the biomimic surfaces are confirmed to enable high corrosion inhibition to Cu. Compared with SHP, OIS shows a 10-fold increment in protection efficiency after being immersed in seawater for 768 h, demonstrating the high corrosion inhibition to protect Cu. The galvanic corrosion inhibition by SHP and OIS is further evaluated. Taking stainless steel 304 as the counter couple, OIS shows better corrosion inhibition to underneath Cu metal than superhydrophobic surface, demonstrating its promising application for galvanic corrosion protection.