Hierarchical-structure induced adjustable deformation of super carbon nanotubes with radial shrinkage up to 66%

Based on the molecular dynamic (MD) simulations, radial-deformation capabilities of super carbon nanotubes (SCNTs) are investigated under uniaxial tension. The investigations uncover the excellent reversible and adjustable radial-shrinkage characteristics of SCNTs, which are caused by the hierarchical assembly of carbon nanotubes (CNTs). MD simulations show that reversible-deformation ranges of SCNTs can be as much as 50%, depending on the atomistic topology in junction areas. By adopting the geometry design of the hierarchical structure, radial shrinkages of SCNTs can be adjusted in a considerable range of 10%-66%. Chirality is the major factor influencing the radial-shrinkage capability, which brings more than 30% difference. For given requirements of the diameter, shrink capability of SCNT can be enhanced by increasing the length of CNTs or choosing specific chirality. Poisson's ratios of SCNTs are found to be strain-dependent including two variation types, i.e. the monotonic decreasing type and the increase-decrease waving type. By analyzing the structural evolution of Y-junctions, the shrinkage mechanism is revealed to rely on the deformation modes of SCNTs and affected by geometric settings of the hierarchical structure. As a nanometer-scale channel structure with superior reversible and controllable characteristics, SCNTs exhibit great potentials in the applications of nano-pipelines and nano-switchers.

427