Tensile failure mechanisms of individual junctions assembled by two carbon nanotubes

The tensile mechanical behaviors of junctions between carbon nanotubes (CNTs) were experimentally and theoretically studied. For sidewall-contact junctions, we found that tensile failure stress can be enhanced by radial deformation of CNTs. Meanwhile, a re-formation mechanism of junctions expected to contribute to interfacial toughness was found, for which a theoretical prediction was presented. For end-contact junction, it is found that the maximum pulling force is dependent on the diameters and wall numbers of CNTs. Most importantly, the interaction strength between two open-ends of CNTs was first experimentally estimated to be 21 MPa. This study would be helpful not only in understanding the failure behaviors, but also in quantifying the mechanical properties of the CNT-based fibers, films and blocks.