TEMPERATURE-DEPENDENT AGGREGATION STRUCTURES OF FULLERENE-BASED IONOMERS IN ELECTROLYTE SOLUTIONS

We have synthesized fullerene derivatives, C60[CO(CH2)5O(CH2)4SO3Na]6 (FC10S), which consists of a C60 cage covalently bonded with six sulfonated arms for a high water solubility. We study the aggregation structures of the novel C60-derivatives in 0.1 M NaCl aqueous solutions by small angle X-ray scattering (SAXS). In the concentration range studied, 0.5 wt% to 2 wt %, the rod-like structure of FC10S aggregates has a radius of 20 Å and a rod-length about 150 Å at 25°C, and the aggregation structure is insensitive to the concentration change. The aggregates, however, grow in length as the temperature increases, while the radius increases slightly with increasing temperature.