title: Are antagonistic salts surfactants?
abstract: It is well known that surfactants decrease both water/air and water/oil interfacial tensions whereas in contrast inorganic salts increase both. We study a new, third class of surface-active ionic solutes, which have been called antagonistic salts, consisting of an organic group with a small inorganic counterion. These show decreased interfacial tension at the oil/water interface due to a redistribution of the organic group in the oil but do not show any surface activity at the air/water interface and are consequently different from surfactants that lower both tensions. We use a simple modeling using Poisson-Boltzmann theory that accounts for the surface activity of the antagonistic salt at the water/oil interface.
authors.affiliation: van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Dominik
authors.initials: D
authors.lastname: Michler
authors.forename: Noushine
authors.initials: N
authors.lastname: Shahidzadeh
authors.forename: Marise
authors.initials: M
authors.lastname: Westbroek
authors.forename: René
authors.initials: R
authors.lastname: van Roij
authors.forename: Daniel
authors.initials: D
authors.lastname: Bonn