Responsive Polymer-Layered Silicate Hybrids for Anticorrosion

Two-dimensional materials have been introduced in polymer coatings to increase the lifetime of metallic materials by providing barrier properties against corrosive species. Corrosion inhibitors can be inserted into a 2D filler to mitigate the corrosion of metallic materials caused by corrosive species. Current drawbacks of this approach include a poorly controlled release of the inhibitor and the incompatibility of the filler and polymer. To achieve long-term anticorrosion performance, a layered silicate (octosilicate) is modified by surface-graft polymerization with a monomer functionalized with a corrosion inhibitor, 8-hydroxyquinoline. A pH-responsive polymer-inhibitor conjugate, poly(methyl methacrylate-co-8-quinolinyl acrylate), is covalently attached to the silicate and then provides a sustainable release of the corrosion inhibitor upon acidification. The corrosion current density of aluminum alloy substrates (AA2024) coated with poly(methyl methacrylate-co-butyl acrylate) embedding the octosilicate containers is decreased due to a synergistic effect of barrier properties provided by the 2D filler and the pH-responsive release of corrosion inhibitor. This conceptual design can be potentially applied to release molecules such as drugs, fertilizers, or pesticides.