Effects of added surfactant on the dynamic interfacial tension behavior ofacidic oil/alkaline systems

The effects of a ready-made surfactant (sodium dodecyl sulfate) on the dyna mic interfacial tension between a model acidic oil (linoleic acid dissolved in paraffin oil) and various aqueous alkaline (NaOH) systems have been stu died using pendant drop tensiometry at surfactant concentrations both below and above the critical micelle concentration (CMC). Below the CMC the adde d surfactant contributes significantly to a further reduction of interfacia l tension of the reacting acid/alkaline system, whereas above the CMC the a dded surfactant plays an important role in damping the dynamic trends obser ved for the reactive system alone. (C) 2001 Academic Press.