Numerical simulations of the effect of ionic surfactant/polymer on oil-water interface using dissipative particle dynamics

Effects of the ionic surfactant (cetyltrimethylammonium bromide) and polymer (styrene-maleic acid copolymers) on the oil/water interface are studied using dissipative particle dynamics at the mesoscopic scale. Effects of the water content on equilibrated morphology of the oil/water emulsion are studied with the help of ionic surfactant. In addition, oil/water emulsion has the patterns of the compound emulsifier at the very low and very high water content. The interfacial tension increases, reaches maximum, and then decreases with an increase of water content. Both experiments and simulations show that the inorganic salts can improve the interfacial efficiency of the ionic surfactants, and lower the interfacial tension. The influence of polymer number is studied on their ability to reduce interfacial tension. The distributions of interfacial tension and mean interfacial density are predicted. The lower the interfacial tension and faster oil coalescence are, the more polymers are. In addition, the influence of the polymer on the surfactant aggregation behavior of the oil-water interface is discussed. (c) 2016 Curtin University of Technology and John Wiley & Sons, Ltd.