Interaction of Molecules in Solutions of C60 in Polar Solvents

Abstract

The features of fullerene C₆₀ in N-methyl-2-pyrrolidone (NMP) solutions and NMP/water solvents were studied using optical absorption spectroscopy, dynamic light scattering (DLS) and atomic force microscopy (AFM). When 30% distilled water was added to the C₆₀/NMP solution, a bathochromic shift (by ~9 nm) and a hyperchromic effect for the characteristic absorption maximum (~331 nm) for the solution, as well as a relatively weak and broad new absorption region around 440 nm, were found. These optical changes are explained by the partial destruction of C₆₀-C₆₀ and C₆₀-NMP complexes when water is added to the solution, and the formation of new C₆₀-water complexes or mixed solvate shells of C₆₀-NMP and C₆₀-water during their reorganization. It was determined that at a constant concentration of C₆₀ in solutions, the maximum hydrodynamic diameter of the synthesized fullerene nanoaggregates in a C₆₀/NMP solution is ~23 nm, and in a C₆₀/NMP/water solution is ~33 nm.