Autonomous Self-healable Scratch-free Bilayer Anti-corrosion Film

Thin hydrophobic polymer film, which physically prevents an approach of corrosive media, has been widely used as an anti-corrosion coating for metals. Though polymer film effectively passivates surface of metal, it loses its anti-corrosion property once the film is peeled off by physical damage, such as scratches. Corrosion can be propagated from the exposed area even if the area is small. Therefore, for long-term anti-corrosion, the film should be seamless and completely cover the entire metal surface without scratches. In this study, we introduce an autonomously self-healable hydrophobic coating with superior anti-corrosion property by a combination of self-healable/fluorinated polymers. Schiff-base linkages based polydimethylsiloxane (SC-PDMS) is used as a primary protection layer against corrosive media. The SC-PDMS matrix with the dynamic imine bonds allows scratch-free metal protection layer by reproducible damage healing property. In addition, we applied polytetrafluoroethylene (PTFE) thin film at the surface of the SC-PDMS, which suppresses the reaction of imine bond with water and helps to maintain long-term anti-corrosion property. Eventually, this simple coating of bilayer structure with SC-PDMS and PTFE shows an effective scratch-free corrosive resistance, providing a new way of long-term use of metals.