title: Adsorption Kinetics of Alkylphosphine Oxides at Water/Hexane Interface
abstract: A pendant drop technique has been used to study the adsorption of a nonionic surfactant, an alkyldimethylphosphine oxide (C13DMPO), at the water/hexane interface. The measured interfacial tensions exhibit a steep initial decrease, pass through a minimum, and then level off at a value which depends on the initial surfactant concentration in the drop. This time dependence of the interfacial tension can be interpreted by an adsorption with a subsequent transfer of the surfactant into the second bulk phase, hexane. Measurements of the distribution coefficient show that the solubility of C13DMPO is much higher in hexane than in water. A qualitative model is proposed which describes the observed dynamic interfacial tensions.
authors.affiliation: Max-Planck-Institut fur Kolloid- und Grenzflachenforschung, Rudower Chaussee 5, Berlin-Adlershof, D-12489, Germany
authors.initials: M
authors.lastname: Ferrari
authors.initials: L
authors.lastname: Liggieri
authors.initials: F
authors.lastname: Ravera
authors.initials: C
authors.lastname: Amodio
authors.initials: R
authors.lastname: Miller