Environmentally responsive semi-interpenetrating network microcapsules with enhanced stability for corrosion protection

Dynamic, responsive microcapsules present innovative solutions for mitigating corrosion and environmental challenges associated with CO₂ capture, utilization, and storage. For their prospective integration into practical applications, these microcapsules must possess structures that optimally balance responsiveness and structural integrity under harsh acidic environments. Here, we report robust pH-responsive microcapsules (RRMCs) that are synthesized using a dynamic complexation-diffusion assembly approach, incorporating polyelectrolytes of varying molecular weights. The RRMCs feature high encapsulation efficiency (∼86%), enhanced stability and sustained controlled release capabilities (up to 14 days). The use of the RRMCs for the controlled release of small molecules, such as benzotriazole (BTA, a widely employed corrosion inhibitor), is demonstrated. The programmed and controlled pH-dependent release behaviour of BTA provides effective protection of metal substrates in an acidic environment. Furthermore, theoretical calculations elucidate the relationship between controlled release and the adsorption mechanism. This strategy offers substantial advancements in the development of responsive microcapsule systems for applications in CO₂-related corrosion control and material durability in harsh environments.