NMR and ESR Studies on the Microenvironmental Properties of Sodium Perfluorooctanoate and Cetyltrimethylammonium Bromide Mixed Micellar Solutions

The microenviromental properties of sodium perfluorooctanoate(SPFO) and cetyltrimethylammonium bromide(CTAB) mixed micellar solutions were studied by using ESR, NMR and surface tension measurement al the air/water interface. The mixed anionic fluorocarbon and cationic hydrocarbon surfactants in this special case have higher surface activity since it is not universal for any type of syatem. 1 H NMR results show that there is strong interaction between cationic surfactant and anionic surfactant either as hydrocarbon surfactant or fluorocarbon surfactant mixture due to strong electric static interaction of opposite charge head group, synergistic to form the mixed micelles, and indicating diat SPFO molecules penetrate into the interior of CTAB micelles. ESR using 5-doxyi stearic acid label technique reveals the increase of microviscosity of the mixed micellar interface.