Small-Angle Neutron Scattering and Photon Correlation Spectroscopy Investigation on Buckminsterfullerene Solutions

Small-Angle Neutron Scattering (SANS) and Photon Correlation Spectroscopy (PCS) findings on Buckminsterfullerene (C₆₀) solutions are presented. The analysis of SANS data allows to characterize the shape and to determine the value of the gyration radius of C₆₀ dissolved in CS₂, a solvent capable to guarantee a good contrast for the neutron probe. We obtained information about the conformation of fullerene in solution, and, by means of comparisons with experimental and theoretical data existing in literature, we found a confirmation that the gyration radius R_g is independent on concentration. PCS measurements were performed on fullerene/organic solvents (toluene, chloroform and CCl₄) solutions. Since the diffusion coefficient is related, through the Stokes-Einstein relation, to the scatterer hydrodynamic radius, R_H, we have obtained information about the conformation of fullerene in solution and about the character of the structural and hydrodynamic interaction.