Chemical Physics and Dynamics of Surfaces – Complex liquids, foams and emulsions

Liquid foams (such as aqueous foams or concentrated emulsions) are made of dense packings of soft particles (gas bubbles or droplets) in a (immiscible) liquid. They are used in a variety of practical and industrial applications, as in pharmaceutical products, remediation processes, or synthesis of aerated materials. Moreover, complex liquid foams where the continuous phase itself is a complex fluid are increasingly encountered. A fine tuning of the structural, ageing and mechanical properties of these jammed complex fluids is a key-point for the final product to achieve its desired morphology and functional properties. On the fundamental ground, complex liquid foams raise many open questions on their structure, ageing and mechanical response. For instance, how do soft jammed materials with tunable attractive interparticle forces flow? How does a geometrical confinement impact on their structure and mechanical response? Can ageing processes be inhibited by complex liquid foams such as gelled foams or foamed emulsions? Our experiments and numerical simulations aim at identifying the physio-chemical local mechanisms underlying the macroscopic behaviors. Our experimental approach combines multiple light scattering probes, microscopy and rheometry.

Caption: (Top) A multilayer foam confined between two plates and subjected to a shear strain. (Bottom) Confocal image of a concentrated oil-in-water emulsion.

Publications 

• P. Guyot, A. Kraynik, D. Reinelt, S. Cohen-Addad. Elastic behavior of confined soap froth. Soft Matter, Royal Society of Chemistry, 2019, 15 (41), pp.8227-8237. https://hal.sorbonne-universite.fr/hal-02962548

• H. Bey, F. Wintzenrieth, O. Ronsin, R. Höhler, S. Cohen-Addad. Stabilization of foams by the combined effects of an insoluble gas species and gelation. Soft Matter, Royal Society of Chemistry, 2017, 13, pp.6816-6830. https://hal.sorbonne-universite.fr/hal-01596063
• M. Le Merrer, R. Lespiat, R. Hoehler, S. Cohen-Addad. Linear and non-linear wall friction of wet foams. Soft Matter, Royal Society of Chemistry, 2015, 11 (2), pp.368-381. https://hal.archives-ouvertes.fr/hal-01239401
• R. Höhler, S. Cohen-Addad, D.J. Durian, Multiple light scattering as a probe of foams and emulsions. Current Opinion in Colloid & Interface Science, Elsevier, 2014, 19 (3), pp.242-252. https://hal.archives-ouvertes.fr/hal-01239405
• S. Cohen-Addad, R. Höhler. Rheology of foams and highly concentrated emulsions. Current Opinion in Colloid & Interface Science, Elsevier, 2014, 19 (6), pp.536-548. https://hal.archives-ouvertes.fr/hal-01239406
• G. Ovarlez, S. Cohen-Addad, K. Krishan, J. Goyon, P. Coussot, On the existence of a simple yield stress fluid behavior. Journal of Non-Newtonian Fluid Mechanics, 2013. 193: p. 68–79. https://hal.archives-ouvertes.fr/hal-00716376
• M. Le Merrer, S. Cohen-Addad, R. Höhler. Duration of bubble rearrangements in a coarsening foam probed by time-resolved diffusing-wave spectroscopy: Impact of interfacial rigidity. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, American Physical Society, 2013, 88 (2), pp.022303. https://hal.archives-ouvertes.fr/hal-01239411
• S. Costa, R. Höhler, S. Cohen-Addad. The coupling between foam viscoelasticity and interfacial rheology. Soft Matter, Royal Society of Chemistry, 2013, 9 (4), pp.1100-1112. https://hal.archives-ouvertes.fr/hal-01239407
• S. Costa, S. Cohen-Addad, A. Salonen, R. Höhler. The dissipative rheology of bubble monolayers. Soft Matter, Royal Society of Chemistry, 2013, 9 (3), pp.886-895. https://hal.archives-ouvertes.fr/hal-01239408
• O. Pitois, S. Cohen-Addad, R. Höhler. Flow in Foams and Flowing Foams. Annual Review of Fluid Mechanics, Annual Reviews, 2013, 45, pp.241. https://hal.archives-ouvertes.fr/hal-00786935