Interfacial displacement of nanoparticles by surfactant molecules in emulsions.

The remarkable stability of nanoparticles attached to oil-water interfaces in macroemulsions hinders controlled detachment of these particles from emulsions. In this work it is shown that adding surfactant molecules which preferentially adsorb at the oil-water interface displaces nanoparticles from the interface. Surfactant adsorption at the oil-water interface is energetically favoured and readily occurs on mixing nanoparticle-stabilised oil-in-water emulsions with surfactant solutions.