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Using Asymmetric Flow Field-Flow Fractionation (AF4) to Determine C60 Colloidal Size Distributions
Citation:
ISAACSON, C., X. MA, AND D. BOUCHARD. Using Asymmetric Flow Field-Flow Fractionation (AF4) to Determine C60 Colloidal Size Distributions. Presented at Gordon Research Conference, Environmental Sciences: Water, Holderness, NH, June 22 - 27, 2008.
Impact/Purpose:
To use asymmetric flow field-flow fractionation (AF4) to determine fullerene aggregate size distribution as a function of ionic strength and surfactant concentration.
Description:
The formation of aqueous fullerene suspensions by solvent exchange, sonication, or extended mixing in water is widely reported. Commonly used methods for determining the size of these aggregates rely on static and dynamic light scattering, electron microscopy (EM), or atomic force microscopy (AFM). Light scattering techniques are limited by poor resolution and sample heterogeneity, while EM and AFM techniques require extensive sample preparation which may alter aggregate size. Asymmetric flow field-flow fractionation (AF4) is a fractionation technique which is able to separate particles ranging from 1 nm to 10 µm based on particle diffusion coefficients. When combined with in-line with light scattering detectors, AF4 methods can be developed for the separation and size determinations of mono- or polydisperse samples. AF4 fractionation methods using NaCl, Tris and HEPES buffers, and the surfactants sodium dodecyl sulftate and FL-70 (a mixture of anionic and cationic surfactants) were developed to determine the size distribution of fullerene suspensions generated by a range of solvent exchange and extended stirring techniques.