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

Abstract

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) (PTUS_X) 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.