Promoting healing progress in polymer composites based on Diels-Alder reaction by constructing silver bridges

Polymer composites with self-healing ability are highly desired for applications in advanced modern devices. Here, we report on self-healing polymer composites consisting of silver deposited-carbon nanotubes hybrid nanoparticles (CNT-Ag) as fillers and self-healable polyurethane (DAPU) as a matrix based on thermally reversible Diels-Alder reaction. The results indicated that as the hybrid filler loading is 1 wt%, the composites not only obtained a high-strength (~15.97 MPa) and high healing efficiency (~90.1%) by increasing filler loading after healing, but also enhance thermal conductivity (~1.65 Wm⁻¹ K⁻¹) and obviously shorten its healing progress in comparison with other composites in the case of the same healing time. Given that Ag_NPs deposited on the surfaces of the CNTs act as bridges to link the adjacent CNTs and reduce interfacial thermal resistance, which can effectively explain the reasons for the obtained high mechanical strength and healing efficiency and promoting healing progress in the polymer composites. This work may offer a novel strategy for balancing relation between mechanical property, healing ability and healing progress in the field of self-healing materials application.