Reverse Water-in-Fluorocarbon Microemulsions Stabilized by New Polyhydroxylated Nonionic Fluorinated Surfactants

Abstract

New polyhydroxylated nonionic perfluorosurfactants C_<i>n</i>F_2<i>n</i>+1-CH₂-O-SO₂-NHCONH-C(CH₂OH)₃ have been synthesized, and their capacity for stabilization of reverse water-in-fluorocarbon microemulsions has been extensively studied. These investigations showed that, regardless of the composition used, transparent one-phase systems could not be obtained if the fluorinated surfactants were used without a sufficient amount of a semifluorinated alcohol. The mixed oil phase used to prepare microemulsions consisted of a 9:1 mixture of perfluorohexane and 1<i>H</i>,1<i>H</i>,2<i>H</i>,2<i>H</i>-perfluorohexan-1-ol. Various scattering techniques, dynamic light scattering (DLS), small-angle X-ray (SAXS), and neutron scattering (SANS) have been used for structural characterization of these fluorinated microemulsions. Valuable information on the size, shape, and internal colloidal structure in these novel fluorinated microemulsions is described and discussed.