Molecular dynamics simulations of the transformation of carbon peapods into double-walled carbon nanotubes

The transformation of carbon peapods (encapsulated fullerenes in nanotubes) into doublewalled nanotubes was studied using molecular dynamics simulation. The simulations reproduce the two main trends known experimentally: the production of low-defect nanotubes and the templating effect of the outer tube. The process involves a low-temperature polymerization of the fullerenes followed by higher temperature self-assembly into a tube. Modelling of this second stage is made possible by the use of the Environment-Dependent Interaction Potential, a large number of atoms and long-time annealing. Analysis shows that the outer tube acts as a container for the self-assembly process, analogous to previous simulations and experiments in which free surfaces, either external or internal, template the formation of highly ordered sp(2) phases. (C) 2010 Elsevier Ltd. All rights reserved.