Asymmetric, continuum-structured self-healable composite conductors based on WPU/MXene/AgNW with microphase-separated structures for balanced healing and mechanical properties

Flexible strain sensors capable of detecting minute mechanical signals and easily adaptable to various irregular surfaces have garnered significant interest for applications in structural health monitoring, early detection, and failure prevention. As state-of-the-art smart materials, these flexible strain sensors should possess highly sensitive sensing capabilities, prolonged durability, and the ability to self-repair. In this study, 1,8-diamino-P-menthane (MD) is incorporated into a waterborne polyurethane (WPU) backbone to induce a microphase separation structure that balances mechanical properties while enhancing self-healing capabilities through hydrogen bonding. Consequently, a blend of self-healing WPU, MXene, and AgNW was employed to fabricate composite conductors featuring an asymmetric continuum structure that exhibits exceptional electrical conductivity and self-healing properties. The distinctive laminate architecture of MXene enables the sensitive detection of signals generated by both bending and tensile deformation (up to 400 %).