Surface polyfluorinated micelles

Three novel polyfluorinated cationic surfactants and the corresponding thre e hydrocarbon analogues were synthesized. All of the surfactants formed glo bular micelles in water. The micellar formation was monitored by five indep endent methods. The results of the NMR measurements and the other four meth ods using the anionic dye Rose Bengal (RB) and anilinonaphthalenesulfonic a cid as probe molecules agreed well with each other. The polyfluorinated mic elles had rather low cmc values, on the order of 10(-5) M. All of the micel les had similar aggregation numbers around 50-60. Using a detailed NMR rela xation study following aa addition of paramagnetic Mn2+ ions to the bulk wa ter phase, the polyfluorinated micelles were shown to have a very unique mi crostructure wit the perfluoroalkyl chain extending straightforwardly to th e bulk water phase. The micropolarity around the ammonium group and the mic roviscosity in the core of the micelles were estimated using the probe mole cules RE and perylene. The local oxygen concentration in the micelles was e stimated from the NMR longitudinal relaxation time T-1. The microstructure of water distributed within the micelles is discussed with relation to the observed local oxygen concentration. The rigidity of the micelle is also di scussed using the mobility of each nuclei estimated from the T-1 data. The unique protecting effect of the micelles against attack by hydroxide radica ls generated in the bulk water phase using Fenton's method was examined usi ng a bleaching reaction of RE as a probe molecule. The surface polyfluorina ted micelles exhibited a greater protective effect than either CTAB or the hydrocarbon analogue surfactant micelles. This protective effect is discuss ed in relation to the unique microstructure of the surface polyfluorinated micelles.