Fullerenes containing water molecules: a study of reactive molecular dynamics simulations

Abstract

A different technique was used to investigate fullerenes encapsulating a polar guest species. By reactive molecular dynamics simulations, three types of fullerenes were investigated on a gold surface: an empty C₆₀, a single H₂O molecule inside C₆₀ (H₂O@C₆₀), and two water molecules inside C₆₀ ((H₂O)₂@C₆₀). Our findings revealed that despite the free movement of all fullerenes on gold surfaces, confined H₂O molecules within the fullerenes result in a distinct pattern of motion in these systems. The (H₂O)₂@C₆₀ complex had the highest displacement and average velocity, while C₆₀ had the lowest displacement and average velocity. The symmetry of molecules and the polarity of water seem to be crucial in these cases. ReaxFF simulations showed that water molecules in an H₂O molecule, H₂O@C₆₀, and (H₂O)₂@C₆₀ have dipole moments of 1.76, 0.42, and 0.47 D, respectively. A combination of the non-polar C₆₀ and polar water demonstrated a significant reduction in the dipole moment of H₂O molecules due to encapsulation. The dipole moments of water molecules agreed with those in other studies, which can be useful in the development of biocompatible and high-efficiency nanocars.