Molecularly Engineered Tough and Room-Temperature Self-Healing Polyurethanes for Resistive Strain Sensors

Abstract

Polymers have made great progress in the field of wearable flexible sensors due to their high flexibility, low cost, and lightweight. The exceptional mechanical properties and inherent self-healing capabilities enable the polymer sensor to function effectively in challenging operational environments. To achieve this, we employed o-aromatic diaminodisulfide and 1,3-dihydroxyacetone from biomass as key components to synthesize polyurethane urea elastomers rich in hydrogen bonds (named PUSS). The material exhibits strong mechanical characteristics (tensile strength >10 MPa, elongation at break >2000%, toughness >140 MJ m–3). The hydrogen bonding interactions of the materials were examined, confirming how they actively promote self-healing. By incorporating MXene and carbon nanofiber into the PUSS matrix, we developed a resistive sensor with robust mechanical properties, high sensitivity, and excellent self-healing capabilities. At room temperature, PUSS exhibited an impressive self-healing efficiency of 85.11% for tensile strength and 79.41% for elongation at break. When employed as a sensor, PUSS maintained a consistent resistance change rate even after being subjected to 50% strain following cutting and self-healing.