Formation of Fullerene Clusters in Carbon Disulfide: Data on Small-Angle Neutron Scattering and Molecular Dynamics

Fullerene solutions in carbon disulfide are studied by small-angle neutron scattering (SANS). In addition to earlier experiments on the given system, the range of measured transmitted impulses is extended and the influence of solution preparation methods on C-60 cluster formation in these solutions is studied. It is shown that the formation of large C-60 clusters (with a size of about 10 nm) is due to nonequilibrium methods of solution preparation. For nonequilibrium dissolution, there is a 10% excess of the observed fullerene size in the solution over the calculated value. It has been established by simulation of the C-60/CS2 interface by molecular dymanics methods that inclusion of how solvent molecules are organized on the C-60 surface leads to a decrease in the fullerene size in the solution, observed by using SANS. In this paper, the effect of excess R g is explained by the presence of small clusters in the solution (approximately 10% of dissolved C-60 molecules). It is discovered that there is a time variation in the concentration of the saturated solution. The explanation of this effect using a model of formation and sedimentation of large clusters (with a size of 100 nm or more) is proposed.