Dragonfly wing-inspired architecture makes a stiff yet tough healable material

Summary

Mechanically robust and healable polymers are in high demand for the intelligent architecture, aerospace engineering, and auto industry; however, most of them suffer from brittle fracture owing to the inherent conflict between stiffness and toughness within polymer systems. Inspired by the microstructure of dragonfly wings, we show how brittle, stiff, and healable materials can become defect tolerant by strategies ranging from molecular design to structural processing. Transition metal carbides/carbonitrides form an interconnected mechanical framework, similar to the rigid nervure in dragonfly wings, to stabilize the growth and slow down the extension of crack, while the initially glassy healing polymer closely bonds to rigid framework through powerful interfacial supramolecular interactions, playing a key role in the soft membrane dissipating stress energy. Compared with initial polymers, the obtained SP/MXene (SPM) nanocomposite exhibits an increase in fracture toughness and flexural strength (54.3- and 25.0-fold, respectively), exceptional thermal stability, mechanical and functional repairability, and good electromagnetic interference shielding.