A Superstrong and Reversible Ionic Crystal-Based Adhesive Inspired by Ice Adhesion
Lili Liu1+ , Ziyang Liu+1 , Yongyuan Ren1+ , Xiuyang Zou1, Wansu Peng2, Weizheng Li1, Yiqing Wu1, Sijie Zheng1, Xiaoliang Wang2*（王晓亮）,and Feng Yan1*（严锋）
1College of Chemistry, Chemical Engineering and Materials Science, Soochow Universit,Suzhou 215123 (China)
2School of Chemistry and Chemical Engineering, Nanjing University
Nanjing 210023 (China)
+ These authors contributed equally to this work.
Angew. Chem. Int. Ed. 2021, 60, 8948--8959
In this study, we developed a superstrong and reversible adhesive, which can possess a high bonding strength in the adhesive state and detach with the application of heating. An ionic crystal (IC) gel, in which an IC was immobilized within a soft-polymer matrix, were synthesized via in situ photo-crosslinking of a precursor solution composed of N, N-dimethyl acrylamide (DMAA) and a melted IC. The obtained IC gel is homogenous and transparent at melt point. When cooled to the phase transition temperature of the IC, the gel turns into the adhesive with the adhesion strength of 5.82 MPa (on glasses), due to the excellent wetting of melted gel and a thin layer of crystalline IC with high cohesive strength formed on the substrates. The synergistic effects between IC, polymer networks and substrates were investigated by solid state H-1 NMR and molecular dynamics simulation. Such an adhesive layer is reversable and can be detached by heating and subsequent re-adhesion via cooling. This study proposed the new design of removable adhesives, which can be used in dynamic and complex environments.