Arresting bubble coarsening: A two-bubble experiment to investigate grain growth in the presence of surface elasticity

Abstract

Many two-phase materials suffer from grain-growth due to the energy cost which is associated with the interface that separates both phases. While our understanding of the driving forces and the dynamics of grain growth in different materials is well advanced by now, current research efforts address the question of how this process may be slowed down, or, ideally, arrested. We use a model system of two bubbles to explore how the presence of a finite surface elasticity may interfere with the coarsening process and the final grain size distribution. Combining experiments and modelling in the analysis of the evolution of two bubbles, we show that clear relationships can be predicted between the surface tension, the surface elasticity and the initial/final size ratio of the bubbles. We rationalise these relationships by the introduction of a modified Gibbs criterion. Besides their general interest, the present results have direct implications for our understanding of foam stability.

Surfactant Crystals as Stimulable Foam Stabilizers: Tuning Stability with Counterions

“…Despite this, surfactant foams tend to have a limited stability of only a few hours. Colloidal particles and certain proteins are extremely efficient in creating mechanically resistant surface layers to stop coalescence and coarsening all together (Gonzenbach et al, 2006;Salonen et al, 2016;Stocco et al, 2011;Tcholakova et al, 2008Tcholakova et al, , 2017. Particles can also gel or get stuck in the foam structure to block drainage (Bey et al, 2017;Guillermic et al, 2009;Haffner et al, 2014;Khidas et al, 2014;Louvet et al, 2010).…”

Stabilization of foams by the combined effects of an insoluble gas species and gelation

“…22 Alternatively, nanoparticles adsorbed at the interfaces can arrest coarsening as they form an elastic skin able to oppose mechanical resistance to the deformation of the interfaces. 11,23 -another physicochemical method makes use of a gas mixture containing a small amount of a species which is insoluble in water. If the soluble gas diffuses out of a bubble that thus becomes smaller than its neighbours, the concentration of the insoluble species in this bubble increases, leading to the build up of an osmotic pressure that is opposed to the Laplace pressure.…”

Pressure–deformation relations of elasto-capillary drops (droploons) on capillaries

“…The condition α = 1/2 has therefore received particular attention and is often called the "Gibbs criterion" since the physical response of a system may change fundamentally around this value. This is known, for example, for the case of bubble dissolution and foam coarsening 40,44 .…”

“…However, since the Gibbs modulus and the dilational modulus can vary independently as a function of strain, there is no contradiction between the two definitions. Using the Gibbs modulus and assuming its independence of strain amounts to choosing a particular type of constitutive law which appears to describe well some experimental systems 7,40 .…”

“…Within the current desire to describe complex liquid interfaces [1][2][3][4][5][6][7] , two scientific communities meet, accustomed to treating either drops or bubbles with fluid-like interfaces, or capsules and balloons whose membranes have solid-like mechanical properties. 0a Institut Charles Sadron, CNRS UPR22 -Université de Strasbourg, Strasbourg, France; Fax: 33 (0)3 88 41 40 99; Tel: 33 (0)3 88 41 40 43; E-mail: Wiebke.Drenckhan@ics-cnrs.unistra.fr 0b Sorbonne Universités, UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, 75005 Paris, France; Email: hohler@insp.upmc.fr 0c Université Gustave Eiffel , 5 Bd Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallé cedex 2, France.…”