Ellipsometry Study of the Adsorption of Asphaltene Films on a Glass Surface

摘要

Asphaltene adsorption from a toluene solution on a glass surface was studied as a function of concentration, at ambient temperature and atmospheric pressure. The thickness of the asphaltene film measured by ellipsometry was found to be in the 20—298 nm range. The film thickness was found to increase by 38—70 nm after 24 h. Solutions containing asphaltene mixtures from different crude oils result in significant variations in film thickness when compared with single asphaltene cases. For CN-Ceuta and DM153-Ceuta mixtures, a diminution was observed, whereas an increase was found with the DM153-Furrial mixture. Finally, the results attained with asphaltenes in which low molecular weight compounds have been removed suggest a film swelling effect due to the alkyl-type resins which are found to modify the colloidal properties of the aggregated asphaltenes in agreement with the literature.