Syntheses of novel fluorocarbon surfactants with oxyethylene groups

Abstract Three anionic fluorocarbon surfactants with oxyethylene groups, sodium bis[2-{2-(perfluoroalkyl)ethoxy}ethyl] 2-sulfosuccinate C n F 2 n +1 -CH 2 CH 2 OCH 2 CH 2 OCOCH 2 CH(SO 3 Na)COOCH 2 CH 2 OCH 2 CH 2 C n F 2 n +1 ( n FEOS; n = 4, 6, or 8), were prepared from ethylene carbonate, maleic anhydride, corresponding alcohols having a polyfluoroalkyl chain, and sodium hydrogensulfite. The surfactants were highly water-soluble, and their Krafft points ( K p ) were below 0°C. The K p values of n FEOS were lower than those of conventional fluorocarbon surfactants, sodium bis[2-(perfluoroalkyl) ethyl] 2-sulfosuccinate C n F 2 n +1 CH 2 CH 2 OCOCH 2 CH(SO 3 Na)COOCH 2 CH 2 C n F 2 n +1 ( n FS; n = 4, 6, or 8). The surface tension at cmc ( γ cmc ) of n FEOS showed very low values, and the cmcs of 4FEOS and 6FEOS were smaller by about one order of magnitude than those of n FS surfactants at the same fluorocarbon chain length n . It should be noted that the introduction of oxyethylene groups enhances the hydrophilicity and micellar forming ability of n FEOS compared to n FS.