Self-healing and mechanically robust poly(thiourea-disulfide) elastomers based on three types of synergistic dynamic bonding

Self-healing polymers (SHPs) improve sustainability by increasing the longevity of materials and equipment. However, a single self-healing mechanism cannot realize the balance between mechanical and self-healing properties. Herein, we report a poly(thiourea-disulfide) (PTUSX) elastomer prepared via an amine-isothiocyanate click reaction. Due to its similar structure to polyurethane, the optimized sample PTUS8 exhibits strong mechanical properties. The synergistic effects of three types of dynamic bonding (disulfide bonds, thiourea bonds, and hydrogen bonds) empower PTUS8 to exhibit desirable self-healing capabilities at ambient temperatures. Moreover, the soft-hard segments design endows PTUS8 with flexibility and toughness. In addition, a solid polymer electrolyte membrane has been fabricated by adding a lithium salt to PTUS8, and it displays high ionic conductivity and can recover the original conductivity after self-healing. Thus, these results not only indicate that the PTUS8 elastomer has considerable potential for application in solid-state lithium batteries, but they also provide new ideas for the development of novel SHPs by combining the synergistic effects of several different types of dynamic bonding. The synergistic effects of three types of dynamic bonding endow poly(thiourea-disulfide) elastomers with desirable self-healing capabilities and mechanical properties at ambient temperatures.