Aggregate development in C60/N-methyl-2-pyrrolidone solution and its mixture with water as revealed by extraction and mass spectroscopy

Abstract The aggregate development in C 60 /N-methyl-2-pyrrolidone (C 60 /NMP) solution with time is studied by the extraction (hexane) and mass spectroscopy. It is shown that only molecular C 60 in NMP is extracted in hexane, which makes it possible to follow a change in the concentration of non-aggregated fullerene in C 60 /NMP during the aggregate growth. It is concluded that almost all fullerene dissolved in NMP is in the aggregates after one month. The reorganization of the aggregates is detected when water is added to the aggregated solution C 60 /NMP. Both methods prove that in this case individual fullerene molecules are detached from the aggregates, which contradicts somewhat to complete insolubility of C 60 in water.