Functional partition strategy in assistance by shear thinning/self-healing effect to prepare durable anti-corrosion coating

The application of self-healing polymers in anti-corrosion coatings is restricted by their nonautonomous healing ability and poor long-term durability. In this paper, we propose a functional partition strategy assisted by the shear thinning effect to overcome the above restriction. The shear thinning effect was achieved by preparing a branched ethyl acrylate-acrylonitrile copolymer (B-PEA). The B-PEA coating exhibits multiple autonomous self-healability at room temperature (1.5 h) and in a salt solution (2 h), with a high adhesion strength of 3.4 MPa. To further improve the performance, a functional partition architecture combining superhydrophobic barrier and self-healing multilayers was constructed. The introduction of the superhydrophobic barrier layer largely increases the low-frequency impedance modulus |Z|f-0.01Hz and salt solution resistance time to 3.9 × 1010 Ω⋅cm2 and 3600 h, respectively, compared to a pristine B-PEA coating. The introduction of the B-PEA layer provides the barrier layer with room-temperature self-healing ability (2 h), and increases the long-term |Z|f-0.01Hz and salt solution resistance time in the presence of scratches to 7.7 × 109 Ω⋅cm2 and > 3600 h, respectively. The as-prepared superhydrophobic anti-corrosion coating system combines long-term durability and room-temperature autonomous self-healability in harsh salt-solution environments, and thus has a high potential for anti-corrosion applications.