Partially unzipping carbon nanotubes: A route to synchronously improve fracture strength and toughness of nanocomposites inspired by pinning effect of screw

Carbon nanotube (CNT) reinforced nanocomposites (CNTRNs) have been regarded as the most promising substitutes for traditional carbon fiber reinforced composites, due to their excellent multi-functional properties. However, the weak CNT-matrix interface which impairs the mechanical properties of CNTRNs is always an issue, limiting their practical applications. Here, inspired by strong pinning effect of screws, we partially unzipped the CNTs into graphene nanoribbons (GNRs) and a screw-like CNT/GNR hybrid (CGH) nanostructure was proposed to reinforce the nanocomposites. It was found that the fracture strength, Young’s modulus and fracture toughness of CGH reinfroced nanocomposites can be boosted by 155 %, 89 % and 117 %, respectively, comparing to those of CNTRNs. The molecular dynamic simulation on pullout of CGHs from matrix revealed that the CNT-GNR junction can lead to a mechanical interlocking, which can not only hinder the pullout of CGH, but also cause remarkable matrix shear deformation, contributing to energy dissipation to a large extent. In addition, the morphology of CGHs can be tuned by changing structural chirality of CNTs, by which the interfacial properties can be further improved. This work opens a new route to engineer high-performance nanocomposites, and provides an in-depth understanding on the mechanical enhancement of CNT-based nanocomposites.