Enhanced self-healing properties of epoxy-based active anticorrosion coatings via facile hydrophobic PDMS modification

Corrosion inhibitors self-healing anticorrosion coatings have garnered significant attention due to their exceptional performance. However, sustained exposure to corrosive solutions at the damaged interfaces of single- function self-healing coatings can cause the metal substrates to corrode and corrosion inhibitors to be released prematurely. This research reports a synergistic anticorrosive coating with self-healing and superhydrophobic attributes. This bi-function coating is fabricated through a one-step spraying method by mixing the epoxy resin (EP) matrix with polydimethylsiloxane (PDMS) and benzotriazole (BTA) loaded mesoporous silica (MS). EP with excellent chemical resistance and adhesion, and green PDMS provide low surface energy for coating, while MS is used to load corrosion inhibitor BTA and form a rough surface. The developed EP/MS/BTA/PDMS coating demonstrates a remarkable hydrophobic property, featuring a water contact angle of 155.3 +/- 2 degrees and a sliding angle of 4.9 degrees. Even after 40 cycles of sandpaper wear and 100 cycles of tape peeling, it still exhibits excellent water repellency. The electrochemical measurements demonstrate that synergetic effect of superhydrophobic surface and BTA significantly enhance the corrosion protection of metals. It is notable that the |Z| f = 0.01 Hz value (3.34 x 107 Omega cm2) of the EP/MS/BTA/PDMS coating is three orders of magnitude higher than that of the EP coating. Moreover, a remarkable corrosion inhibition be achieved in the damaged area due to the introduction of BTA. When the coating is scratched, the superhydrophobic effect resists a large amount of corrosive solution at the same time, BTA forms strong chelation with Mg2+ ions, creating a protective film on the damaged area. This study provides an environmentally benign, economical, and facile method for designing self-healing super- hydrophobic corrosion-resistant coatings.