Self‐Healing Waterborne Polyurethane Elastomers Based on Multiple Reversible Bonds with Good Mechanical Performance for Composite Conductors

Abstract As a functional material, polyurethane elastomers have a wide range of applications in fields such as flexible wearable devices and healthcare but are prone to damage during use. As a result, they are often incorporated with self‐healing properties to prolong their service life. The preparation of polyurethane elastomers with excellent mechanical and self‐healing properties has become crucial to addressing this issue. In this study, a new self‐healing system with excellent mechanical properties is developed by reacting butanedione oxime (DMG) and gallic acid (GA) with isocyanate (─NCO) to introduce oxime‐carbamate bonds and phenol‐carbamate bonds into waterborne polyurethane. The triple dynamic reversible synergistic network formed through multiple reversible covalent bonds and hydrogen bonds enhances the mechanical and self‐healing properties of the waterborne polyurethane elastomers. The results demonstrate that the synthesized polyurethane elastomer films exhibit excellent mechanical properties (strength of 41.02 MPa, elongation at break of 955.9%, toughness of 112.17 MJ m −3 ) and self‐healing properties (healing efficiency of 91.21%). In addition, the composite conductor (DG‐WPU‐CNTs) prepared by incorporating this polyurethane elastomer with carbon nanotubes (CNTs) exhibits excellent sensitivity, stability, and self‐healing properties, providing a basis for its application in flexible wearable devices.