Molecular simulation of spontaneous encapsulation of C_(60) cluster into single-walled carbon nanotubes

摘要

The encapsulation process of C_(60) clusters into single-walled carbon nanotubes (SWNT) in supercritical carbon dioxide (scCO_2) and carbon disulfide (CS_2) has been simulated. In scCO_2, C_(60) molecules usually form cluster and the C_(60) molecules from the cluster is able to, spontaneously and step by step, encapsulate into SWNT. However, in CS_2, no C_(60) cluster is formed and no encapsulation of C_(60) can be observed. The simulation result provides a theoretical support on the experimental hypothesis that C_(60) cluster formation is beneficial for the filling of SWNTs in solution. However, our simulation suggests that it is not prerequisite to avoid the solvent insertion during the encapsulation, which is in contrast with the previous conclusion. The thermodynamic free energy in the C_(60) cluster insertion has been computed in order to understand the molecular origin of the process.