Chemical covalent connection of carbon nanotubes for related structural manufacturing: A molecular dynamics study

Carbon nanotubes (CNTs) with junction plays an important role in nanomaterial and nano-devices, especially the junction constructed by covalent bonds. However, the connection process between single-walled carbon nanotubes (SWCNTs) could hardly be observed experimentally on an atomic scale and its connection strength is difficult to accurately measure. Hence, this work investigates the atomic reconstruction and evolution of the structure of SWCNTs at joint area and the connection strength of the joined SWCNTs by molecular dynamics (MD) simulation. Various connection effects between two types of typical SWCNTs, i.e. metallic SWCNTs and semiconducting SWCNTs, are investigated for the smooth covalent connection with high mechanical strength. The simulation results indicate that energy parameters (pulse-widths, pulse number, and temperature) and structure parameters (relative rotation angles, end type and chirality of SWCNTs) have great influence on the connection process. However, the size of energy zone and diameter for both armchair and zigzag SWCNTs make little difference to its connection process and connection strength under certain conditions. This study reveals that whether armchair or zigzag SWCNTs, there is an optimal set of energy and structure parameters to connect them into an ideal hexagonal junction with high mechanical strength. The critical technical parameters are obtained in this study for the optimal covalent connection of SWCNTs, which provides enlightening significance to manufacture the covalent SWCNTs junctions.