Interaction of C_(60) with Water: First-Principles Modeling and Environmental Implications

摘要

The nature of fullerene-water interactions has been the subject of much research and debate. Specifically, the presence of a stabilizing, negative surface potential on colloidal aggregates of C_(60) in water is unexpected, given the neutral nature of pure carbon, and is not well understood. Previous simulation efforts have focused on the C_(60)- water interaction using molecular dynamics simulations that lacked the ability to account for charge transfer and distribution interactions. In this study, first-principles density functional theory was used to analyze the fundamental electronic interactions to elucidate the polarization and charge transfer between water and C_(60). Simulations show that charge is inductively transferred to the C_(60) from water molecules, with subsequent polarization of the C_(60) molecule. In a case with two neighboring C_(60) molecules, the charge polarization induces a charge onto the second C_(60). Simulation suggests that this charge transfer and polarization may contribute at least partly to the observed negative surface potential of fullerene aggregates and, combined with hydrogen bonding network formation around C_(60), provides a fundamental driving force for aggregate formation in water.