New insights into effect of the electrostatic properties on the interfacial behavior of asphaltene and resin: An experimental study of molecular structure

•The effect of the Asphaltene and Resin molecular geometrical feature, and structure on their interfacial behavior were studied.•New electrical indexes were introduced to examine to assess the polarity of the asphaltene and resin fraction.•Based on the Zeta potential result, IEP and NP, PO index, the dominant surface charge of the asphaltene and resin was negative.•The Mg2+ promoting the resin molecules to accumulate and adsorb at the interface more than the Ca2+ and, for asphaltene was vice versa.•Three distinct adsorption behaviors for the asphaltene and resin were observed by increasing the ions' strength.