(473e) Coalescence Behavior of Asphaltene-Coated Oil-Water Interfaces

Asphaltenes are polyaromatic molecules that can make up a significant fraction of some crude oils. These molecules are known to be interfacially active, and are believed to form rigid adsorbed layers at oil-water interfaces which enhance emulsion stability. In this work, asphaltenes are dispersed in an aromatic rich solvent. Interfacial properties of this well dispersed system are quantified by measuring the dynamics of interfacial tension and dilatational elasticity. A specific sample of asphaltene is shown to be interfacially active, but shows only moderate interfacial elasticity at an oil-water interface with no observation of rigidification of the interface. Coalescence experiments are performed on oil-water interfaces both with and without asphaltenes adsorbed. Results show that adsorbed asphaltenes are able to promote the coalescence process by minimizing the electrostatic repulsion forces between oil-water interfaces, even when adsorbing from the oil phase. The outcome of this work provides a new perspective on the stability of oil-water emulsions with asphaltenes.