Trigger and response mechanisms for controlled release of corrosion inhibitors from micro/nanocontainers interpreted using endogenous and exogenous stimuli: A review

Metallic corrosion can lead to both economic losses and environmental pollution due to undesired chemical and biochemical reactions. Furthermore, there are a number of drawbacks associated with different corrosion prevention and mitigation techniques. In view of these challenges, corrosion inhibitor-based smart micro/nanocontainers (CISCs) with stimuli-responsive functionality emerge as an important alternative technical approach in dealing with metallic corrosion. The development of CISCs involves controlled release corrosion inhibitors and self-healing coatings. This review focuses on the trigger and response mechanisms of controlling the discharge of corrosion inhibitors from micro/nanocontainers (a core–shell or layered structure) into aqueous solution under endogenous (pH, redox, and ion-exchange), exogenous (temperature, magnetic field, and light), and multiple stimuli. When these CISCs are embedded into coating materials, the self-healing effect of the coating can manifest to protect various types of metals. In this review effort, different types of CISCs are classified for the first time into the following three categories: inorganic, organic, and organic-inorganic hybrid. We also discuss application scope, future perspectives, and research strategies for CISCs in the hopes of increasing the life of corrosion protection and providing inspiration in related fields.