Molecular Dynamics Simulation of C60 Encapsulation into Single-Walled Carbon Nanotube in Solvent Conditions

Abstract

In this work, molecular dynamics simulations were performed to study the process and mechanism of fullerene (C60) encapsulation into single-walled carbon nanotube (SWNT) in three kinds of solvents: supercritical CO2 (scCO2), CS2, and water. It was demonstrated that a C60 molecule could spontaneously insert into the SWNT in scCO2, which is in good agreement with the experimental observation. However, no encapsulation of C60 was observed in CS2 and water during the simulation period. We also, for the first time, simulated the PMF (potential of mean force) profile along the C60 inserting path. The occurring free energy barrier near the entrance of the SWNT could hinder the insertion of C60, which is determined by the interaction strength between solvent and C60, as well as the solvation structures around C60. The C60–SWNT interaction provides the driving force in the filling, whereas the solvent-induced force instead offers an obstructing effect. It is revealed that both the solvent-induced free energy barri...