Solubilization of alcohols in single and mixed surfactant aqueous solutions containing fluorocarbon surfactant

Abstract

The solubilization of hydrocarbon and fluorocarbon alcohols in single and mixed aqueous solutions containing fluorocarbon surfactant has been studied. Surfactants used are lithium dodecyl sulfate (LiDS), lithium perfluorooctane sulfonate (LiFOS), lithium perfluorooctanoate (LiPFO), and hexaethyleneglycol dodecyl ether (6ED). In single surfactant systems, the partition coefficients of the alcohols between anionic micelles and water are greater for the surfactants which have the same kind of alkyl chain as the alcohols than for the surfactants having a different kind of alkyl chain to the alcohols. The standard free energies calculated from the partition coefficients indicate that the transfer of the alcohols occurs more favorably to the micelles consisting of the same kind of alkyl chain as the alcohols than of the different kind of alkyl chain. Also, the mixed surfactant systems LiDS-LiFOS, LiFOS-LiPFO and 6ED-LiFOS have been characterized by the regular solution parameter β and the alcohol partition coefficient. In the LiDS-LiFOS system with a positive β value, the partition coefficients of both hydrocarbon and fluorocarbon alcohols are greater than in single surfactant systems. In the LiFOS-LiPFO system exhibiting almost ideal mixing, the partition coefficients of both hydrocarbon and fluorocarbon alcohols change ideally, whereas the partition coefficients of the fluorocarbon alcohols are greater than those of the hydrocarbon alcohols. By contrast, in the 6ED-LiFOS system with negative β values, the partition coefficients of both alcohols are lower than in single surfactant systems.