Mechanically Robust, Intrinsic Self-Healing Polyurethane Enabled by NIR-Photothermal Conversion of MXene/Polydopamine Hybrids

Balancing mechanical strength and self-healing properties in self-healing polyurethane remains a critical challenge for the development of high-performance self-healing materials. Here, this study constructed a network of multilevel dynamic hydrogen bonds and oxime-carbamate bonds within intrinsic self-healing polyurethane, laying the foundation for high strength and reparability. To enable efficient and controllable healing, a hybrid photothermal material (MHP) was developed through chemical bonding between MXene and polydopamine nanoparticles, leveraging their synergistic photothermal effect in the near-infrared region to enable precise and remote activation of the healing process. The resulting polyurethane nanocomposite (IB-PU₁/MHP_1%) demonstrates outstanding comprehensive properties: a tensile strength of 58.8 MPa, an elongation at break of 790%, and a toughness of up to 149.2 MJ/m³. Under near-infrared (NIR) light irradiation (808 nm), the material surface temperature rapidly rises to 91.1 °C within 180 s, enabling efficient healing within 30 min at a power density of 1.00 W/cm², with a healing efficiency of 82.7%. Moreover, the material exhibits a hardness of approximately 57.2 Shore A and shows no permanent deformation after tensile fracture. This work not only overcomes the challenge of high-temperature healing in outdoor applications through photothermal conversion but also provides a new molecular design strategy for high-performance self-healing PUs, broadening their potential applications in flexible electronics, smart coatings, and related fields.