High resolution transmission electron microscopy analysis of conical carbon nanotubes formed in the high isostatic pressure apparatus

Carbon nanotubes with “herringbone” layers structure synthesized in high isostatic pressure apparatus were studied by High Resolution Transmission Electron Microscopy (HRTEM) methods. Seven different values of semi-apex angles of graphene layers were observed in different nanotubes. It is shown that semi-apex angles approximately equal to 5, 15, 25 и 35 can be regarded only to the scroll structure of the nanotubes, while 10, 20 and 30 can be regarded to both scroll either nested graphene layers curved to cones due to the embedding of the pentagon’s to them. Thus, the observation of all (seven) of these values of semi-apex angles testifies presence of scroll nanotubes in the sample under study, though it does not exclude presence of nested-cone nanotubes.