The use of nanoparticles as stabilisers in foams and emulsions has gained great attention in recent years, and is a subject of interest for many scientific and industrial fields; such as food colloids, cosmetics, chemical cleaners, metal foams and mineral flotation. Most research has focused on the use of nanoparticles as a substitute for traditional surfactants; however research into combination systems is also very important. This is firstly because many natural and industrial systems contain combinations of different species and also because of the evidence for stabilisation synergy.

Using partially hydrophobic, 300nm silica particles and non-ionic Triton X-100 surfactant, the foam stability of various mixed systems was investigated to probe the parameters required for stabilisation enhancement (synergy). These results helped highlight the possible interactions between the two species at the air-water interface. The particle-surfactant-interface interactions were related to studied changes in system surface tension, absorbance, surface pressure behaviour, turbidity and interfacial rheology. Results indicate the critical parameters required to improve stability in systems of mixed species (such as in flotation), but also illustrate the hurdles to using novel particles as foaming agents.