EXPANSION OF MIXED ANIONIC NONIONIC MICELLES CAUSED BY SOLUBILIZATION OF ORGANIC SOLUTES

The micelle size was determined by dynamic light scattering for mixed anionic non-ionic micelles containing solubilized organics. The surfactants used were sodium dodecyl sulfate and hexadecyl polyoxyethylene ethers (C16POEn where n = 10, 20, 30 or 40). For pure or mixed surfactant systems, the diameters of micelles which contain solubilized n-octane are almost independent of solute concentration, while micelles containing solubilized 1-octanol increase in size with increasing solute content. The change in micellar size for systems containing 1-octanol is influenced by hydrophilic group interactions between anionic and non-ionic surfactants in the mixed system.