UV-triggered self-healing polyurethane with enhanced stretchability and elasticity

Light-activated self-healing (LSH) materials have received extensive attentions recently due to their environmentally friendly repairing methods and excellent healing performance. However, the current reported LSH materials have poor mechanical strength and elasticity, which limit their applications. Herein, a novel series of coumarin-based polyurethanes with enhanced mechanical properties and elasticity have been synthesized which possessed a dramatic breaking stress of 27 MPa with a high breaking strain of 890%. Besides, the energy dissipation efficiency in continuous stretch cycles of the as-prepared polyurethanes varied negligibly, which proves the as-prepared LSHs have excellent elasticity. Meanwhile, after cutoff, the polymers exhibited excellent self-healing performance by UV irradiation for 40 min and the best healing efficiency of strain, stress and Young's modulus were 84%, 92%, 94%, respectively. The prepared self-healing polyurethanes showed great potential applications in the fields of smart materials such as self-healing coatings, electrochemical sensors and devices, electronic skin, etc.