Collapse and stability of single- and multi-wall carbon nanotubes

Abstract

The collapse and stability of carbon nanotubes (CNTs) have important implications for their synthesis and applications. While nanotube collapse has been observed experimentally, the conditions for the collapse, especially its dependence on tube structures, are not clear. We have studied the energetics of the collapse of single- and multi-wall CNTs via atomistic simulations. The collapse is governed by the number of walls and the radius of the inner-most wall. The collapsed structure is energetically favored about a certain diameter, which is 4.12, 4.96 and 5.76 nm for single-, double- and triple-wall CNTs, respectively. The CNT chirality also has a strong influence on the collapsed structure, leading to flat, warped and twisted CNTs, depending on the chiral angle.

Ab-initioinvestigation of point-like defects in AlN nanowires

“…In order to determine if the increased stability of the collapsed phase is valid for larger radii, a single walled nanotube with 40 atoms/super-cell was also investigated. The collapsed nanotube, which is basically a two layer AlN ribbon, has an energy 0.15 eV lower per Al-N pair than the cylindrical one, indicating a result which is in agreement with the ones presented in [16], [17] and [18] for carbon nanotubes. The bond lengths of the defect-free R 2 nanowire (Fig.…”

Multiple radial corrugations in multiwalled carbon nanotubes under pressure

“…4. For instance, the AA stacking of carbon atoms [59] in the radial direction will lead to an effective load transfer between neighbouring layers. Thereby, rigid inner walls can support effectively the mechanical instability of outer walls.…”

Transversality Condition in Continuum Mechanics

“…However, Liu et al (2004) performed simulations on the formation of fully collapsed SWCNTs with the atomic scale finite element method, and proposed that for armchair SWCNTs, collapse occurs for the critical radius (for n=30) is R max  2.06 nm, which is also different from the aforementioned results. In fact, this value of critical radius of 2.06 nm was verified by TEM observations, which demonstrated that there exists a collapsed SWCNT of 2.5 nm in radius (Xiao, et al, 2007). In spite of the above cited studies on the collapse of CNTs, there are hitherto no analytical solution for the collapse problem of CNTs, which involves large deformation and strong geometric nonlinearity.…”