Effect of Mixed Surfactant upon Stability and Particle Size of Emulsion

An effect of a mixed surfactant of SDS and homogeneous octaethylene glycol dodecyl ether (8ED) upon the stability and particle size of an octane-in-water emulsion was studied. The mixed surfactant solutions were found to exhibit equi-interfacial-tension over a wide concentration region of a mixed 8ED; the SDS concentrations were 6, 8, and 20 mmol dm−3. The emulsion prepared by using mixed surfactant solution in such a concentration region showed a similar mean particle size. When SDS concentration was kept at 8 or 20 mmol dm−3, The emulsions prepared by the mixed surfactant solutions had similar stability, independently of the mixed 8ED concentration. In the presence of 1 mmol dm−3 of SDS, the stability of the emulsions increased with the increasing concentration of mixed 8ED. In the case of SDS concentration of 6 mmol dm−3, the emulsion was most stable at 1×10−3 mol dm−3 of mixed 8ED.