Large variations in the onset of rippling in concentric nanotubes

Mechanical behavior of carbon nanotubes in the rippled and buckled phase

“…The arc-discharge tubes are, to begin with, much stiffer than the CVD tubes as a result of their higher degree of crystallinity. 24 Moreover, the relative drop in E for the arc-discharge tubes are much larger than the drop for the CVD tubes as is shown in Fig. 2.…”

“…11, 24 Here we are focussing on the behavior after the very onset of buckling and rippling. This is most often referred to as a non-linear regime, but this can be a little misleading as we find an approximately linear dependence also above the critical strain.…”

“…Only recently has the use of non-optical force sensors 23 provided a true joining of AFM with regular electron microscopy instruments, and this has enabled detailed studies of the critical bending-strain for buckling and rippling in carbon nanotubes. 11,24 These measurements have shown that both the initial stiffness and the rippling onset are very sensitive to the amount of defects in the nanotubes.…”

“…25 The actual effect is larger than predicted though, and measurements have shown a variation by a factor of three in the critical strain, for CNTs with the same outer diameter. 24 The bending stiffness in the rippled phase has also been suggested to depend on the number of walls in a multi-walled carbon nanotube (MWCNT), but the modeling results vary from a rather weak, 26 to a very strong dependence.…”

Measurements of the transport gap in semiconducting multiwalled carbon nanotubes with varying diameter and length

“…There are strongly different mechanical properties in arc-discharge and CVD MWNTs according to Ref. [51]. Thus there is significant variation in the properties of MWNTs, and this paper represents the domain of well ordered, relatively close to ideal MWNT structures.…”