Europhys. Lett.
Volume 74, Number 3, May 2006
Page(s) 533 - 539
Section Interdisciplinary physics and related areas of science and technology
Published online 29 March 2006
Europhys. Lett., 74 (3), pp. 533-539 (2006)
DOI: 10.1209/epl/i2005-10546-7

Slow viscoelastic relaxation and aging in aqueous foam

S. Vincent-Bonnieu, R. Höhler and S. Cohen-Addad

Université de Marne-la-Vallée, Laboratoire de Physique des Matériaux Divisés et des Interfaces, UMR 8108 du CNRS - 5 Boulevard Descartes 77454 Marne-la-Vallée cedex 2, France

received 5 December 2005; accepted 1 March 2006
published online 29 March 2006

Like emulsions, pastes and many other forms of soft condensed matter, aqueous foams present slow mechanical relaxations when subjected to a stress too small to induce any plastic flow. To identify the physical origin of this viscoelastic behaviour, we have simulated how dry disordered coarsening 2D foams respond to a small applied stress. We show that the mechanism of long time relaxation is driven by coarsening-induced rearrangements of small bubble clusters. These findings are in full agreement with a scaling law previously derived from experimental creep data for 3D foams. Moreover, we find that the temporal statistics of coarsening-induced bubble rearrangements are described by a Poisson process.

83.60.Bc - Linear viscoelasticity.
83.80.Iz - Emulsions and foams.
62.20.Hg - Creep.

© EDP Sciences 2006