Mussel-inspired composite coating with self-healing and ultrahigh anti-corrosion performance based on synergy design strategy

Designing effective strategies to satisfy the anti-corrosion requirements in harsh deep-sea environment still remains a large challenge. Herein, inspired by mussel, we prepared a novel reinforcement composite filler by bridging glass flakes (GFs) and graphene oxide (GO) with polydopamine (PDA), and then introduced them into EP resin to obtain the superior coating named PDA-GFs@GO/EP. The novel composite coating shows superior interfacial barrier capability due to the dual barrier network formed by "labyrinth effect" of GFs and the good shielding effect of GO. In addition, PDA can chelate with Fe3 + and Fe2+ to achieve the self- healing effect. What's more, the addition of hybridized fillers improves the epoxy crosslinking density, which greatly enhanced the structural strength and adhesion value between coating/steel interface. Consequently, the composite coating exhibits improved interfacial stability, self- healing ability and long-time anti-corrosion performance even in harsh deep-sea environments with high hydrostatic pressure. The bond strength of the PDA-GFs@GO/EP coating/steel interface is 78.8 % higher than EP coating. The |Z|0.01 Hz after 15 days of immersion in a coupled simulated deep-sea environment kept at 4.90 x 1011 Omega center dot cm2, approximately 100 times that of pure EP coating, showing excellent corrosion resistance. This research addresses the challenge of integrating GFs with GO and overcomes the toughie of coating rapidly delaminating from steel interfaces under the extreme hydrostatic pressure conditions of deep-sea environments, which can provide new insights into the design of long-term anticorrosive composite coatings for the harsh deep-sea environments.