Role of surfactants on the approaching velocity of two small emulsion drops

► We model the hydrodynamic interaction between two approaching spherical drops. ► The model accounts for the surface material properties (rheology and diffusivity). ► The role of surfactants soluble in the continuous and/or disperse phases is studied. ► Increasing the surfactant chain length will decrease the interfacial mobility. ► The surfactants soluble in the disperse phase decrease the emulsion stability.