Monodisperse Perfluoroalkyl Oxyethylene Nonionic Surfactants with Methoxy Capping: Synthesis and Phase Behavior of Water/Surfactant Binary Systems

New monodisperse surfactant molecules with a poly(oxyethylene) methoxy-capped chain for the hydrophilic head and a perfluoroalkyl moiety for the hydrophobic tail are synthesized. The principle of solid‒liquid phase transfer reactions is used. Surface tension measurements of aqueous solutions (γ ~ 20 mN m^-1) show slow organization of the surfactant film at the water/air interface for the fluorocarbon tail. Values of the critical concentration and comparisons with the hydroxy-capped analogous surfactants are consistent with a small influence of the hydrophobic effect of the methoxy terminal group on the polar head. The results of phase behavior in aqueous binary systems are discussed. As expected, the replacement of OH group by an OMe group effectively reduces the hydrophilicity of the surfactant but does not change dramatically its phase behavior in water.