Diffusivity of Asphaltene Molecules by Fluorescence Correlation Spectroscopy

Using fluorescence correlation spectroscopy (FCS) we measure the translational diffusion coefficient of asphaltene molecules in toluene at extremely low concentrations (0.03−3.0 mg/L):  where aggregation does not occur. We find that the translational diffusion coefficient of asphaltene molecules in...

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Bibliographic Details
Published in:The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2006-07, Vol.110 (26), p.8093-8097
Main Authors: Andrews, A. Ballard, Guerra, Rodrigo E, Mullins, Oliver C, Sen, Pabitra N
Format: Article
Language:English
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Summary:Using fluorescence correlation spectroscopy (FCS) we measure the translational diffusion coefficient of asphaltene molecules in toluene at extremely low concentrations (0.03−3.0 mg/L):  where aggregation does not occur. We find that the translational diffusion coefficient of asphaltene molecules in toluene is about 0.35 × 10-5 cm2/s at room temperature. This diffusion coefficient corresponds to a hydrodynamic radius of approximately 1 nm. These data confirm previously estimated size from rotational diffusion studied using fluorescence depolarization. The implication of this concurrence is that asphaltene molecular structures are monomeric, not polymeric.
ISSN:1089-5639
1520-5215
DOI:10.1021/jp062099n