Characterization of Athabasca asphaltenes by small-angle X-ray scattering

Colloidal dispersions of Athabasca asphaltenes in toluene were studied at room temperature by small-angle X-ray scattering (SAXS). Both 5% and 15% dispersions were found to be polydispersed spheres with the main distribution peak at a concentration-independent average radius of 33 A. The main distribution peak was skewed to the right, similar to a Schultz distribution. Owing to interparticle correlation, a small proportion of the particles could be interpreted as forming larger aggregates, the size of which appeared to decrease on increasing the concentration of dispersion.