A Facile Method to Balance the Fast Self-Healing Ability and Low Energy Dissipation in Self-Healable Polymers

The rapid self-healing ability and low energy dissipation of self-healing polymers (SPs) are difficult to balance, which limits their practical applications. This study proposes a simple method to prepare SPs simultaneously with improved self-healing ability and reduced energy dissipation by in situ polymerization of acrylamide (AM) and poly(ethylene glycol) methyl ether methacrylate (MPEG) in an aqueous solution of deep eutectic solvent (DES). The DES acts as a plasticizer, promoting the movement of polymer chains. At the same time, it forms a hydrogen bond complex with the polymer chains, accelerating the formation rate of hydrogen bonds. This enables the material to recover rapidly structural via instantaneous hydrogen bond reformation upon stress removal, coupled with a significant decrease in hysteresis loss. This synergistic mechanism thus achieves a balance between rapid self-healing ability and low energy dissipation. In addition, DES endows the material with ionic conductivity. As a strain sensor, PAM-5 exhibits ultra-low electrical hysteresis, a rapid response, as well as good stability, and fatigue resistance. It can be used to monitor external mechanical stimuli and human body movements. This strategy provides a new approach for the design of high-performance self-healing polymers.