title: Fast relaxations in foam.
abstract: Aqueous foams present an anomalous macroscopic viscoelastic response at high frequency, previously shown to arise from collective relaxations in the disordered bubble packing. We demonstrate experimentally how these mesoscopic dynamics are in turn tuned by physico-chemical processes on the scale of the gas-liquid interfaces. Two specific local dissipation processes are identified, and we show how the rigidity of the interfaces selects the dominant one, depending on the choice of the surfactant.
authors.affiliation: Laboratoire de Physique des Matériaux Divisés et des Interfaces, FRE 3300 CNRS, Université Paris-Est, 5 Bd Descartes, Champs-sur-Marne, 77454 Marne-la-Vallée Cedex 2, France.
authors.forename: Kapilanjan
authors.initials: K
authors.lastname: Krishan
authors.forename: Ahmed
authors.initials: A
authors.lastname: Helal
authors.forename: Reinhard
authors.initials: R
authors.lastname: Höhler
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cohen-Addad