Theoretical investigation of thermally induced coalescence mechanism of single-wall carbon nanohorns and their mechanical properties

Abstract

Using classical molecular dynamics (MD) simulations, this study investigates the heat treatment induced coalescence of single-wall carbon nanohorns (SWCNHs) with different conical angles. It is found that the formation of a metastable Venturi-like structure from two individual nanohorns is the result of thermal motions around potential basins and successive Stone–Wales (S–W) transformations following initial graphene–graphene junctions. The coalescence and melting behaviors of the metastable nanohorn junctions are studied. The simulation results reveal that the coalescence temperature and the melting temperature are both dependent on the conical angle of the nanostructure. Specifically, it is found that the coalescence temperature and the melting temperature are lower in the nanohorn junctions with sharp nanohorns. Finally, the influence of the conical angle on the mechanical response of the metastable nanohorn junctions under tensile deformation is examined. The results show that the metastable synthesis with a sharper conical angle has a greater yielding strength than those with a blunt conical angle.