title: Simultaneous conductivity and viscosity measurements as a technique to track emulsion inversion by the phase-inversion-temperature method.
abstract: Two kinds of transitions can occur when an emulsified water-oil-ethoxylated nonionic surfactant system is cooled under constant stirring. At a water-oil ratio close to unity, a transitional inversion takes place from a water-in-oil (W/O) to an oil-in-water (O/W) morphology according to the so-called phase-inversion-temperature method. At a high water content, a multiple w/O/W emulsion changes to a simple O/W emulsion. The continuous monitoring of both the emulsion conductivity and viscosity allows the identification of several phenomena that take place during the temperature decrease. In all cases, a viscosity maximum is found on each side of the three-phase behavior temperature interval and correlates with the attainment of extremely fine emulsions, where the best compromise between a low-tension and a not-too-unstable emulsion is reached. The studied system contains Polysorbate 85, a light alkane cut oil, and a sodium chloride brine. All transitions are interpreted in the framework of the formulation-composition bidimensional map.
authors.affiliation: Centre de Génie Chimique des Milieux Rheologiquement Complexes, Ecole Nationale superieure des Industries Chimiques, Nancy, France.
authors.forename: Joachim
authors.initials: J
authors.lastname: Allouche
authors.forename: Eric
authors.initials: E
authors.lastname: Tyrode
authors.forename: Véronique
authors.initials: V
authors.lastname: Sadtler
authors.forename: Lionel
authors.initials: L
authors.lastname: Choplin
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Salager