Self-peeling hydrogel with strong adsorption to patina revive slumbered bronze relics by nondestructive cleaning

Bronze artifact holds immense significance as a vital component of the world's cultural heritage. However, the conventional approaches employed to eliminate the corrosive rust layer induced by “bronze disease” suffer from numerous limitations. We prepared a novel self-peeling double network polyacrylamide/chitosan–silver (PAAm/CS–Ag) hydrogel with a high rust-removal rate. The strong attraction of the silver ion coordination network to rust molecules and chlorides provides the foundation for the adsorption ability of the hydrogel to rust. The PAAm/CS–Ag hydrogel firmly and uniformly adheres to the bronze surface layer, strongly adsorbing the bronze molecules to its interior. After a period, the hydrogel naturally peels away from the surface, completely stripping the adsorbed bronze layer and forming a complete hydrogel “inscription topography.” Drawing upon the unique properties of the gel, we have successfully employed it in the restoration process of bronze artifacts, including Western Zhou bronze pieces and bronze figures from Sanxingdui. This application has facilitated the removal of rust from their surfaces, effectively reviving their original visual splendor. Undoubtedly, this achievement bears immense importance for the preservation and conservation of bronze artifacts.