COUNTERION EFFECT ON THE IMMISCIBILITY OF FLUOROCARBON AND HYDROCARBON SURFACTANTS IN MIXED MICELLES

We examined the influence of the addition of lithium chloride or diethylammonium chloride on micellar miscibility. The miscibility of fluorocarbon and hydrocarbon surfactants in a micelle was evaluated by the micellar pseudophase diagram, i.e., mixture cmc's and second cmc's. The addition of LiCl induced an increase of immiscibility in the micelle. The micellar size was rather large with the addition of LiCl and was further increased by the mixing of lithium perfluorooctanesulfonate (LiFOS) and lithium dodecyl sulfate (LiDS). Molecular theory was attempted to describe the nonideal mixtures of fluorocarbon and hydrocarbon surfactants. The calculation also indicated the existence of two kinds of mixed micelles and micellar growth by mixing the fluorocarbon and hydrocarbon surfactants.