Collapse phase diagram of carbon nanotubes with arbitrary number of walls. Collapse modes and macroscopic analog

Y Magnin and F Rondepierre and W Cui and DJ Dunstan and A San-Miguel, CARBON, 178, 552-562 (2021).

DOI: 10.1016/j.carbon.2021.03.031

Carbon nanotubes tend to collapse when their diameters exceed a certain threshold, or when a sufficiently large external pressure is applied on their walls. The radial stability of tubes has been studied in each of these cases, however a general theory able to predict collapse is still lacking. Here, we propose a simple model predicting stability limits as a function of the tube diameter, the number of walls and the pressure. The model is supported by atomistic simulations, experiments, and is used to plot collapse phase diagrams. We have identified the most stable carbon nanotube, which can support a maximum pressure of similar to 18 GPa before collapsing. The latter was identified as a multiwall tube with an internal tube diameter of similar to 12 nm and similar to 30 walls. This maximum pressure is lowered depending on the internal tube diameter and the number of walls. We then identify a tube diameter domain in which the radial mechanical stability can be treated as equivalent to macroscopic tubes, known to be described by the canonical Levy-Carrier law. This multiscale behavior is shown to be in good agreement with experiments on the collapse of O-rings, proposed as a simple macroscopic parallel to nanotubes in this domain. (C) 2021 Elsevier Ltd. All rights reserved.

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