Probing the Molecular Interactions of an Asphaltene Model Compound in Organic Solvents and Aqueous Solutions Using a Surface Forces Apparatus (SFA).

摘要

A fundamental understanding of the molecular interactions between asphaltene molecules in bulk and at oil-water interface is of great value in crude oil production. Yet, the chemical composition and molecular structures of asphaltenes are not fully understood. The objective of this study is to investigate the similarity and disparity between an asphaltene model compound C5Pe and real asphaltene molecules in the context of interaction force profiles, molecular aggregation/adsorption at clay-solvent interfaces. The intermolecular and surface forces of C5Pe in organic solvents and aqueous solutions were directly measured by a Surface Forces Apparatus (SFA). Repulsive forces were observed between asphaltene (and C5Pe) surfaces in pure toluene, and strong adhesion were measured in heptane. pH, salt concentration and Ca 2+ showed strong impact on the interaction of two C5Pe surfaces. Our results provide an important insight into basic interaction mechanism of asphaltene-type molecules and their interfacial activities in O/W and W/O emulsions.