Topological defects could be formed in carbon nanotubes either during processing or during subsequent thermo-mechanical loading. When multiple defects were formed, they interacted with each other, depending upon the distance of separation between them. Earlier studies had shown that, under mechanical loading, such interacting defects coalesced to form a larger defect; ultimately leading to complete failure. While defect coalescence was possible, it had also been observed that some defects could disappear (anneal out) under certain thermo-mechanical conditions. In these molecular dynamics based simulations, it was shown that two 5-7-7-5 type defects (Stone-Wales) in close proximity remained stable when subjected to either pure mechanical loading (tensile strain of 10%) or pure thermal loading (temperatures up to 3000K). On the other hand, the defects annihilated completely under a combination of thermal (2800K) and mechanical loading (under 5%) applied simultaneously. It was suggested that vibrational oscillations, due to thermal effects, combined with atomic separation introduced due to mechanical load could together cause the defects to annihilate whereas either of them acting alone could not do so.

Defect Annihilations in Carbon Nanotubes under Thermo-Mechanical Loading. C.Shet, N.Chandra, S.Namilae: Journal of Materials Science, 2005, 40[1], 27-36