Concentration and solvent effects on structural, dynamical and rheological properties of asphaltene suspensions

The effects of different concentrations and solvents in asphaltene solutions properties were studied using a mesoscale simulation approach named dissipative particle dynamics (DPD). Structural analysis revealed the predominance of parallel stacking between molecular planes. The time evolution of number of aggregates showed that the number of aggregates diminishes for both solvents, which makes sense as initially each aggregate represents isolated molecules. Viscosity has been calculated for all cases, and the results show that solute–solvent interactions have a great impact on the viscosity of the material, which becomes less important as the entropy becomes dominant when mass fraction increases. The viscoelastic behavior of asphaltene suspensions has been analyzed for the first using a molecular dynamics approach. All systems presented greater viscous (liquidlike) behavior under high frequencies, which is consistent with soft particles.