Adsorption isotherms of perfluorocarbon surfactants from aqueous and non-aqueous solutions and friction measurements of perfluorosurfactant-adsorbed alumina

Abstract

Abstract The adsorption of a series of perfluorocarbon surfactants C n F 2n + 1 COONa (n = 6, 7, and 8) and C n F 2n + 1 COOH (n = 6, 7, and 8) on aluminum oxide surfaces has been studied experimentally. Isotherms from aqueous and non-aqueous solutions, respectively, were measured, and the effects of pH and fluorocarbon chain length on the adsorption behavior and the maximum level of adsorption determined. Contact angles and friction coefficients for adsorbed films of surfactant on alumina chips were also measured as a function of pH and surfactant concentration. Friction coefficients were reduced while contact angles increased.