Dual-functional ZIF-8 as a curing promoter and nanocontainer for responsive inhibitor release in enhanced protection of bronze artifacts

The effective conservation of bronze artifacts is hindered by the shortcomings of conventional protective coatings. These materials typically cannot self-repairing after damage, allowing corrosion to progress, and often require high curing temperatures that may damage the bronze artifacts. To address these issues, this study develops a multifunctional epoxy coating based on zeolitic imidazolate framework-8 (ZIF-8). ZIF-8 plays a dual role in this system: as a curing accelerator, its tertiary amine groups catalyze the epoxy curing reaction, significantly reducing the activation energy from 130.74 kJ·mol −1 to 59.06 kJ·mol −1 ; and as a pH-responsive nanocontainer, it encapsulates the corrosion inhibitor benzotriazole (BTA) and releases BTA intelligently upon coating damage and corrosion-induced acidic microenvironment-triggered, enabling active self-repairing. Experimental results show that with a BTA loading of 8 mol% and a filler content of 2.0 wt%, the coating exhibits optimal long-term anti-corrosion performance during a 50-day immersion test. After scratching, the low-frequency impedance modulus of the coating recovers rapidly within 2 h and peaks between 8 and 12 h, confirming its fast self-repairing capability. Raman spectroscopy and theoretical calculations reveal that the repairing mechanism stems from the formation of a stable protective film via Cu N coordination between released BTA and the bronze substrate. This work provides an intelligent protection strategy for bronze artifacts, integrating 70 °C curing with active self-repairing functionality.