Dual-responsive smart MSNs-BTA@PANI nanocontainers for synergistic corrosion protection

Stimuli-responsive active corrosion protection coatings serve as both an effective physical barrier and an active corrosion protection system for metallic substrates. However, their long-term performance is typically limited by the irreversible release of inhibitors and a restricted loading capacity, which hinders their repeated active corrosion protection capability and sustained durability. To address these limitations, we have developed a smart dual-stimuli-responsive active corrosion protection coating (denoted as MSNs-BTA@PANI/PVB) by encapsulating benzotriazole (BTA) within mesoporous silica nanocontainers (MSNs) coated with a polyaniline (PANI) shell. PANI, serving as a reversible molecular switch responsive to pH and redox conditions, enables controlled BTA release, ensuring sustained corrosion inhibition and prolonged service life. UV-vis spectroscopy revealed that in 3.5 wt% NaCl solution, minimal surface-adsorbed BTA was released from MSNs-BTA@PANI nanocontainer under pH change, whereas 0.54 mmol L − 1 release was triggered upon N 2 H 4 . After 50 days of immersion, EIS results showed that the coating containing 0.5 wt% MSNs-BTA@PANI achieved a |Z| 0.01Hz value of 1.14 × 10 5  Ω cm 2 , nearly seven times higher than that of the 0.5 wt% MSNs/PVB coating. This enhancement stems from the synergy between the physical barrier effect of MSNs and the dual-stimuli-triggered release of BTA, enabling effective localized corrosion inhibition. This work provides a reversible and controllable active protection strategy based on dual-responsive nanocontainers for designing durable intelligent corrosion protection coatings.