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Characterizing Fullerene Nanoparticles in Aqueous Suspensions
Citation:
BOUCHARD, D., X. MA, AND C. ISAACSON. Characterizing Fullerene Nanoparticles in Aqueous Suspensions. Presented at American Chemical Society 42nd Western Regional Meeting , Las Vegas, NV, September 23 - 27, 2008.
Impact/Purpose:
To characterize fullerene nanoparticles in aqueous suspensions.
Description:
Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentrations of fullerenes that are many orders of magnitude above their aqueous solubility. Analyzing these suspensions poses challenges in collecting representative suspension samples and in characterizing the fullerene nanomaterials in suspension with respect to particle size, surface potential, and mass. In this study, aqueous fullerene suspensions were formed at pH’s of 4, 7, and 10 in 10mM NaCl equivalent using the extended stirring technique, which does not employ organic solvents, as this technique is more representative of actual environmental conditions. Suspensions were also formed using ground and surface waters. The suspensions were then characterized for fullerene mass concentration, particle size, morphology, and surface potential (zeta potential). Fullerene mass concentration was determined by extracting the fullerenes from the aqueous phase using a liquid-liquid extraction procedure. Fullerenes in the extract were then separated and quantitated by HPLC-UV. Fullerene particle size analysis was achieved using dynamic light scattering, electrophoretic mobilities of fullerene aggregates were measured using laser Doppler velocimetry, and particle size and morphology were evaluated using atomic force microscopy (AFM) and transmission electron microscopy (TEM).