Overview of smart anti-corrosion coatings and their micro/ nanocontainer gatekeepers

Smart anti-corrosion coatings (SACs) have emerged with a significant topic in recent years, providing diverse protection mechanisms with enhanced corrosion protection compared to traditional coatings. Currently, the development of SACs is more typically achieved by embedding micro/nanocontainers loaded with active substances into the coating matrix, enabling these coatings to monitor corrosion processes and actively restore protective functions. This review comprehensively summarizes SACs, focusing on various core components (types and fillers), their roles, and the current state of development. Furthermore, nano-valves with external triggering mechanisms serve as promising gatekeepers in SACs, effectively addressing issues of uncontrolled active agent release and limited container functionality. These gatekeepers can regulate the storage and release of active agents in response to corrosion triggers, significantly enhancing anti-corrosion efficiency and the overall protective performance of the coating. This paper highlights recent advancements, for the first time, in the application of nano-valves as gatekeepers for micro/nanocontainers in SACs. These nano-valves include types such as polymer shells, polyelectrolyte layers, Inh-Mn + complexes, supramolecular assemblies, quantum dots (QDs), layered double hydroxides (LDHs), and metal-organic frameworks (MOFs).