Rationally Constructed Surface Energy and Dynamic Hard Domains Balance Mechanical Strength and Self-Healing...

Polymeric materials that simultaneously possess excellent mechanical properties and high self-healing ability at room temperature, convenient healing, and facile fabrication are always a huge challenge. Herein, we report on surface-energy-driven self-healing energetic linear polyurethane elastomers (EPU) that were facilely fabricated by two-step methods to acquire high healing efficiency and mechanical properties. By constructing surface energy and dynamic hard domains, energetic linear polyurethane elastomers not only obtained high healing ability and mechanical properties at high or room temperature but also avoid the use of some assisted healing conditions and complex chemical structure design and decrease manufacturing difficulty. Based on the interfacial healing physical model, various trends of surface tension, radius, and depth of the crack bottom were calculated to analyze the healing mechanism. We propose that polyurethane elastomers with low junction density could generate excess surface energy resulting from damage and drive self-healing, and incorporating a small amount of disulfide bonds increases the slightly packed hard phase and decreases the healing energy barrier. This work may offer a novel strategy for improving mechanical tensile and healing ability in the field of self-healing material application.