Preparation and Properties of Self-Healing Polyurethane Sensing Materials Synergistically Regulated by Thermoresponsive Imine Bonds and Metal Coordination Bonds

Inspired by biological self-healing systems, we developed a self-healable conductive polyurethane by synergistically integrating multiple dynamic bonds to address damage and performance degradation in flexible sensors subjected to complex deformations. Dynamic imine bonds were incorporated into a waterborne polyurethane backbone via a Schiff base reaction, resulting in a reversible network. Hydroxylated multiwalled carbon nanotubes were added to establish conductive pathways, while metal coordination further developed a dual dynamic cross-linked structure. Among the prepared systems, the Zn 2+ -containing sample exhibited optimal performance, with a tensile strength of 19.99 MPa, an elongation at break of 1111.81%, and a healing efficiency exceeding 90% after 6 h. The thermal properties remained stable, with T 10% slightly decreasing from 294.49 to 288.75 °C and T g from 55.73 to 53.85 °C, which facilitates chain mobility and accelerates self-healing. The synergistic dynamic interactions significantly enhance energy dissipation, fatigue resistance, and electrical stability. Furthermore, the material demonstrates a rapid and repeatable millisecond-level electrical response under strain, underscoring its strong potential for flexible sensing applications.