Mixed Micelle and Mixed Adsorbed Film Formations of Anionic Fluorocarbon-Nonionic Hydrocarbon Surfactant Mixtures Sodium Perfluorooctanoate with MEGA-8, 9 and 10

The formation of mixed micelles and mixed adsorbed films was investigated as a function of the mole fraction of each surfactant mixture for different combinations of an anionic fluorocarbon surfactant, sodium perfluorooctanoate (SPFO) with three nonionic hydrocarbon surfactants, MEGA-8, 9 and 10 (alkyl-N-methylglucamines) in water at 30°C. The results were obtained primarily from surface tension and ESR measurements. The critical micelle concentration (cmc) data for the MEGA-9-MEGA-10 mixed system included those determined from light scattering measurements. Based on the results obtained, the following conclusions were drawn. Mixing of MEGA- n's with SPFO synergetically enhances surface activity, and the cmc vs. composition curves for these show a negative deviation from ideal mixing. Thus possibly, interactions between head groups influence more for the curve than the mutual phobicity between hydrocarbon-fluorocarbon chains. The composition of micelles resembles that of adsorbed films for MEGA- n's-SPFO. ESR data indicate that SPFO and MEGA-n may mix well with each other.