A Highly Efficient Self‐Healing Elastomer with Unprecedented Mechanical Properties

: It is highly desirable, although very challenging, to develop self-healable materials exhibiting both high efficiency in self-healing and excellent mechanical properties at ambient conditions. Herein, a novel Cu(II)-dimethylglyoxime-urethane-complex-based polyurethane elastomer (Cu-DOU-CPU) with synergetic triple dynamic bonds is developed. Cu-DOU-CPU demonstrates the highest reported mechanical performance for self-healing elastomers at room temperature, with a tensile strength and toughness up to 14.8 MPa and 87.0 MJ m-3 , respectively. Meanwhile, the Cu-DOU-CPU spontaneously self-heals at room temperature with an instant recovered tensile strength of 1.84 MPa and a continuously increased strength up to 13.8 MPa, surpassing the original strength of all other counterparts. Density functional theory calculations reveal that the coordination of Cu(II) plays a critical role in accelerating the reversible dissociation of dimethylglyoxime-urethane, which is important to the excellent performance of the self-healing elastomer. Application of this technology is demonstrated by a self-healable and stretchable circuit constructed from Cu-DOU-CPU.