While the behavior of the mixed surfactants is similar to that of DDA or brij-35 (Panel 1C and 2C) in the begining, the long term behavior is found to be quite different in that the oil remains in the aqueous phase, quite likely in the form of oil-in-water emulsions. Very similar behavior was also observed with toluene, xylene and other organic liquids (Figure ). The main conclusion that we can reach from these observations is that neither the anionic nor the non-ionic surfactant forms stable oil-in-water emulsion, whereas stable emulsions are formed with the mixed surfactant, where the coopertivity between the anionic and nonionic surfactants, and the resulting extended H-bond formation appears to play the critical role. See also Figures and, and the associated discussions where this issue was highlighted.