A nacre-inspired thermo conductive and healable nanocomposite captures extremely enhanced stiffness and toughness

Polymer-based nanocomposites that exhibit exceptional mechanical properties, rapid self-healing capability, high thermal conductivity, and superior electrical insulation are highly sought after for thermal management applications in modern electrical systems and electronic devices, owing to their versatility, ease of processing, and cost-effectiveness. However, traditional methods for enhancing thermal conductivity often compromise self-healing ability and mechanical and electrical properties. In this study, inspired by nacre, we propose an innovative approach to fabricating nanocomposites with a hierarchical architecture by incorporating boron nitride nanosheets (BNNSs) into a polyurethane matrix through a bottom-up assembly process and lamination technology. Leveraging the nacre-like layered structure and strong interfacial hydrogen bonding interactions, the nanocomposites were successfully transformed from exhibiting brittle fracture to displaying ductile fracture behavior, effectively reconciling the contradiction of high stiffness and toughness. The unique design of the nanocomposite leads to simultaneous enhancement in stiffness (5.3 times), strength (20.1 times), toughness (337.4 times), and fracture toughness (16.4 times) compared to those of the polyurethane matrix. Additionally, the resulting nanocomposites demonstrate excellent self-healing efficiency (∼98 %), high thermal conductivity (8.1 ± 0.3 W m−1 K−1) and superior electrical insulation property (>1012 Ω cm). Overall, our study provides a promising avenue for fabricating polymer-based nanocomposites for thermal management applications, which exhibit multifunctional properties without compromising on mechanical strength, electrical insulation, and self-healing capabilities.