Dissipative particle dynamics simulation on the properties of the oil/water/surfactant system in the absence and presence of polymer

Dissipative particle dynamics is used to simulate the oil/water/surfactant system in the absence and presence of polymer. Structural properties, interfacial properties, and their dependence on the surfactant concentration, polymer concentration and oil/water ratio were investigated. The snapshots illustrate the variation of the structure of oil/water/surfactant system. In the presence of polymer, the interface is supersaturated at a lower surfactant concentration. The end-to-end distance increases with surfactant concentration and polymer chains but shows weak dependence on the oil/water ratio. The peak of density grows higher with surfactant concentration, but it is not affected by oil/water ratio. The density profiles of polymer grow higher with polymer chains, indicating that most of the polymer chains stay at the interface for stability. Interfacial thickness shows an adsorption of polymer/surfactant complexes at the interface, where the polymer is in an extended conformation at the interface. The formation of polymer/surfactant complexes is favourable for the decrease of oil/water interfacial tension.