Mangrove inspired anti-corrosion coatings

Marine corrosion accounts for one-third of the total corrosion cost and has been one of the greatest challenges for modern society. Organic coatings are known as the most widely used protective means. An effective control of the transport of corrosive substances is the key to the anti-corrosion performance. In nature, the mangrove survives and thrives in marine tidal zones despite high salinity and humidity. We first showed that the mangrove leaves have salt glands that can secrete excessive ions to control the ion transport in and out. Inspired by this, we proposed a design of bio-inspired, anti-corrosion coating that mimics this functional feature, and fabricated the bipolar, hydrophobic coatings by doping ion-selective resins and constructing surface structures, which restrict the transport of corrosive substances and the electrochemical corrosion at the coating/metal interface. Our results show that the bio-inspired coatings effectively block and control the transport of both the Na⁺ and Cl^-, and, together with the hydrophobic surface, the coating system exhibits significantly improved anti-corrosion properties, more than a three orders of magnitude decrease in corrosion current density when compared with the control group (epoxy varnish). Therefore, the mangrove-inspired coatings show a promising protective strategy for the ever-demanding corrosion issues plaguing modern industries.