A Smart Anticorrosive Epoxy Coating Based on Graphene Oxide/Functional Mesoporous Silica Nanoparticles for Controlled Release of Corrosion Inhibitors

When mesoporous nanomaterials and graphene oxide have been used in anti-corrosion coatings, new nanocoatings have attracted greater attention. Adding nano-fillers with special structures and corrosion inhibitors to epoxy coatings has been proven to effectively enhance the corrosion resistance of coatings. However, studies have pointed out that the added corrosion inhibitors are easily degraded by UV light and react with the metal substrate or materials in the coating, resulting in a significant reduction in the service life of the coating. To this end, in this study, the corrosion inhibitor was encapsulated in mesoporous silica with pH response, and the functional silica was composited with graphene oxide to prepare novel graphene oxide/functional mesoporous silica nanoparticles. Coatings with this special filler added have strong anti-corrosion potential and can be applied in marine anti-corrosion contexts, such as containers, in the future. The filler not only has a physical barrier ability but also can effectively prevent the degradation of the inhibitor due to ultraviolet rays. At the same time, in the early stage of corrosion, the release of inhibitors can be effectively controlled by the change in PH to achieve the purpose of preventing corrosion. UV spectrophotometry confirmed the stable encapsulation and controlled release of the inhibitor. Electrochemical-impedance spectroscopy showed that the |Z|0.01 Hz value of the smart anti-corrosion epoxy coating was about 10,000 times higher than that of the pure epoxy coating. Through the FT-IR mapping test, it was found that in the area of mechanical damage, the alkaline environment created by the initial corrosion can induce the release of tannic acid and react with common corrosion products to form iron tannins, which effectively inhibits the further occurrence of corrosion. This method provides an effective method for the design of heavy-duty anti-corrosion coatings.