Exploring Self‐Healing and Switchable Adhesives based on Multi‐Level Dynamic Stable Structure
Hualiang Xu, Shiwei Zhao, Anqian Yuan, Youlong Zhao, Xudong Wu, Zhengkai Wei, Jingxin Lei, Liang Jiang
Abstract
Abstract It is a challenge to develop adhesives simultaneously capable of strong adhesion and efficient switchable ability. Herein, the authors report multifunctional switchable adhesives named Cu 2+ ‐curcumin‐imidazole‐polyurethane (CIPUs:Cu 2+ ) by introducing 1‐(3‐aminopropyl) imidazole and curcumin into polyurethane system crossed by Cu 2+ forming dynamic metal‐ligand bonds. This CIPUs:Cu 2+ has strong adhesion (up to 2.46 MPa) on various material surfaces due to their specially designed functional groups alike the secretions from mussels. It can achieve fast switching speed (30 s) and high switch efficiency through multiple contactless remote stimulations. Importantly, density functional theory (DFT) calculation reveals that such metal‐ligand bonds consisting of two components: stronger Cu 2+ ‐curcumin complexes and weaker Cu 2+ ‐imidazole complexes can aggregate to form multi‐level dynamic stable structure . The special structure can not only be acted as sacrificial sites for easily broken and reformed, allowing efficient switchable adhesion and enormous energy dissipation but also acted as firm sites to maintain the cohesion of the adhesive and the reversible reconstruction network. Intriguingly, the CIPUs:Cu 2+ can achieve self‐healing at room temperature without needing external stimuli. Overall, this strategy can further broaden the design of switchable adhesives in the fields of intelligent gadgets, wearable bio‐monitoring devices, etc.