Preparation and properties of self-healing polyurethane flexible sensing materials enabled by synergistic multiple dynamic bonds

Abstract

Flexible strain sensors are prone to structural damage, conductive network failure, and performance degradation during prolonged service, which limits their practical applications. In this study, we developed a polyurethane-based wearable conductive film (PU-VxDy) featuring a multiple dynamic network by integrating hydrogen bonds, imine bonds, disulfide bonds, and Zn2+ coordination bonds. A Schiff base chain extender (VPP), 2,2'-diaminodiphenyl disulphide (DTDA), Zn2+ coordination, and hydroxylated multi-walled carbon nanotubes (MWCNTs) were synergistically incorporated to enhance mechanical properties, self-healing capabilities, and sensing performance. The multiple dynamic network effectively regulated the microphase structure and chain mobility of the polyurethane. Among all samples, PU-V3D1 exhibited the best overall performance, with a tensile strength of 22.50 MPa, an elongation at break of 2117.35%, and stress and strain recovery efficiencies of 92.08% and 90.36%, respectively, after healing at 60 °C for 6 hours. The material also demonstrated excellent thermal stability, with a maximum decomposition temperature of 416.41 °C. PU-V3D1 displayed rapid and stable strain-sensing behavior, achieving a maximum gauge factor of 2.46, an electrical recovery efficiency of 94.65%, and stable electrical output after 1000 loading-unloading cycles. Furthermore, the sensor enabled reliable real-time monitoring of human motion, showcasing its potential for self-healing wearable electronics.

The authors' abstract, as published at the source. Polymer, 2026 · DOI ↗