Mechanically Interlocked [an]Daisy Chain Adhesives with Simultaneously Enhanced Interfacial Adhesion and Cohesion

Abstract

Adhesives have been widely used to splice and repair materials to meet practical needs of humanity for thousands of years. However, developing robust adhesives with balanced adhesive and cohesive properties still remains a challenging task. Herein, we report the design and preparation of a robust mechanically interlocked [an]daisy chain network (DCMIN) adhesive by orthogonal integration of mechanical bond and 2‐ureido‐4[1H]‐pyrimidone (UPy) H‐bonding in a single system. Specifically, the UPy moiety plays dual roles: cross‐linking for network formation and multivalent interactions with substrate for strong interfacial bonding. Mechanically interlocked [an]daisy chain, serving as the polymeric backbone of the adhesive, is able to effectively alleviate applied stress and uphold network integrity through synergistic intramolecular motions and thus significantly improve the cohesive performance. Therefore, comparative analyses with the control made of the same quadruple H‐bonding network but with non‐interlocked [an]daisy chain backbones demonstrate that our DCMIN possesses superior adhesion properties over a wide temperature range. These findings not only contribute to a deep understanding of the structure−property relationships between microscopic mechanical bond motions and macroscopic adhesive properties but also provide a valuable guidance for optimizing design principles of robust adhesives.