Structural transformation of double-walled carbon nanotube bundles into multi-walled carbon nanotubes induced by current treatment

In this paper, double-walled carbon nanotube (DWNT) bundles can be transformed into multi-walled carbon nanotubes (MWNTs) by electric current treatment in vacuum. The morphology of the transformed MWNTs shows an obvious dependence on power density of the current, which changes from partly transformed MWNTs to collapse MWNTs with the increase of power density. The process of this structural transformation follows the tendency of forming more stable structures, and can be ascribed to the sequential coalescence of DWNTs inside the bundles.