title: The surface tells it all: relationship between volume and surface fraction of liquid dispersions.
abstract: The properties of liquid dispersions, such as foams or emulsions, depend strongly on the volume fraction ϕ of the continuous phase. Concentrating on the example of foams, we show experimentally and theoretically that ϕ may be related to the fraction ϕsof the surface at a wall which is wetted by the continuous phase - given an expression for the interfacial energy or osmotic pressure of the bulk system. Since the surface fraction ϕscan be readily determined from optical measurement and since there are good general approximations available for interfacial energy and osmotic pressure we thus arrive at an advantageous method of estimating ϕ. The same relationship between ϕ and ϕsis also expected to provide a good approximation of the fraction of the bubble or drop surface which is wetted by the continuous phase. This is a parameter of great importance for the rheology and ageing of liquid dispersions.
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. emilie.forel@u-psud.fr.
authors.forename: Emilie
authors.initials: E
authors.lastname: Forel
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. emilie.forel@u-psud.fr.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Rio
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. emilie.forel@u-psud.fr.
authors.forename: Maxime
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. emilie.forel@u-psud.fr.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Beguin
authors.affiliation: School of Physics, Trinity College Dublin, The University of Dublin, Ireland.
authors.forename: Denis
authors.initials: D
authors.lastname: Weaire
authors.affiliation: School of Physics, Trinity College Dublin, The University of Dublin, Ireland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hutzler
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France. emilie.forel@u-psud.fr.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Drenckhan