Self-healing, High-resilience, and UV-curable Polyurethane-urea Elastomers Enabled by Dual Crosslinked Networks

Self-healing polyurethane (PU) elastomers will greatly extend the service life of key components, reduce maintenance costs, and promote sustainability. However, dense hydrogen bonds cannot quickly recover after stretching, causing permanent deformation, while high-temperature and long-duration curing are required for their crosslinking. Therefore, dual crosslinked networks are designed herein to achieve self-healable, high-resilience and UV-curable polyurethane-urea elastomers (PUU-SS-Zn), using polycarbonate diol (PCDL) as the soft segment for entropic elasticity, cystamine (Cy) as a chain extender for disulfide bonds and urea-linked hydrogen bonds, 2-hydroxyethyl acrylate (HEA) as end-capping groups for rapid UV-curing, ZnCl 2 for metal coordination bonds. The resultant elastomers are UV-cured within 100 s, exhibit a transmittance >92%, tensile strength of 11.8 MPa, and elongation at break of 2423%. More importantly, it achieves nearly 100% resilience at 500% strain within 5 s, realizes 99.6% resilience at 1000% strain within 5 min, and maintains 90.2% after multiple cycles. Surface scratches disappear within 30 min at 60 °C, and the self-healing efficiency reaches 93% after 8 h at 80 °C. This self-healable, high-resilience and UV-curable polyurethane-urea elastomer shows great application potentials in flexible sensors and wearable devices.