Preparation and Performance of Self‐Healing Polyurethane Sensing Materials Enabled by Synergistic Dynamic Interactions Between Hydrogen and Disulfide Bonds

ABSTRACT Wearable flexible sensors are widely used in health monitoring but often face mechanical damage and thermal degradation during prolonged use. This study presents a high‐performance waterborne polyurethane elastomer based on synergistic dynamic hydrogen and disulfide bonding. The elastomer is synthesized via a prepolymer method using polytetramethylene glycol (PTMG) as the soft segment and 3,3′,5,5′‐tetrabromobisphenol A (TBBA) with 2,2′‐diaminodiphenyl disulfide (DTDA) as chain extenders, enabling precise structural control. FTIR and TG analyses confirm its structure and thermal properties. An optimal TBBA:DTDA ratio of 4:1 achieves a balance between mechanical strength and self‐healing, with tensile strength of 15.87 MPa, elongation at break of 1316.07%, and healing efficiency above 89%. Incorporating hydroxylated multi‐walled carbon nanotubes (MWCNTs) significantly improves conductivity. At 2 wt% loading, the composite maintains strong mechanical performance and enhanced healing efficiency (> 91%), with tensile strength of 11.38 MPa and elongation of 1049.82%. Thermal stability is improved, with T 90% rising to 418.81°C, residual carbon to 8.08%, and T g increased from 50.36°C to 53.66°C. The resulting films exhibit high sensitivity (GF 0.7–3.93) and stable cyclic behavior, enabling reliable monitoring of various human motions.