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Home > Members > Emmanuelle Rio

Emmanuelle Rio

EMMANUELLE RIO


CONTACT INFORMATIONS


Maître de Conférence (HDR)/Assistant Professor

Laboratoire de Physique des Solides

Université Paris Sud

Bat 510 - RDC Ouest - Bureau 071

91 405 Orsay Cedex

Phone: 0033 (0) 1 69 15 69 60

Mail: rio(at)lps.u-psud.fr


PhD Student/ Publications / Former PhD Students / Manuscripts


PhD STUDENTS


MANON MARCHAND
contact info
JONAS MIGUET
contact info

PUBLICATIONS


Foam coalescence/ Film rupture/ Generation of soap films / Foam coarsening/Foam Drainage/ Particles at the interface / Liquid fraction profile in a foam / Particles in the bulk / Sap flow in trees / Drying of colloidal suspensions / Sliding drops/Dry patches in flowing films

Foam Coalescence


P. Yazhgur, D. Langevin, H. Caps, V. Klein, E. Rio, A. Salonen, “How antifoams act: a microgravity study”, N. P. J. Microgravity, 1, 2015.

E. Rio & A.-L. Biance, "Thermodynamic and Mechanical Timescales Involved in Foam Film Rupture and Liquid Foam Coalescence.", Chem. Phys. Chem., 2014.

E. Rio and D. Langevin, Coalescence in Foams and Emulsions in Encyclopedia of Surface and Colloid Science (Taylor and Francis, 2012).

Film Rupture



L. Champougny, J. Miguet, R. Henaff, F. Restagno, F. Boulogne, E. Rio, Influence of evaporation on soap film rupture, 2018.

L. Champougny, E. Rio, F. Restagno, B. Scheid, The break-up of free films pulled out of a pure liquid bath. Journal of Fluid Mechanics, 811, 499-524, 2017.

B. Scheid, S. Dorbolo, L. Arriaga, E. Rio, “Antibubble dynamics: the drainage of an air film with viscous interfaces.”, Phys. Rev. Letters, 109, 264502, 2012.

L. Saulnier, L. Champougny, G. Bastien, F. Restagno, D. Langevin, E. Rio, “A study of generation and rupture of soap films”. Soft Matter. 10, 2899, 2014.

Generation of Soap Films


L. Champougny, B. Scheid, F. Restagno, J. Vermant, E. Rio, "Surfactant-induced rigidity of interfaces: a unified approach to free and dip-coated films." Soft Matter 2015.

J. Delacotte, L. Montel, F. Restagno, B. Scheid, B. Dollet, H. A. Stone, D. Langevin, and E. Rio, “Plate Coating: Influence of Concentrated Surfactants on the Film Thickness”, Langmuir, 28, 3821−3830, 2012.

L. Saulnier, F. Restagno, J. Delacotte, D. Langevin, E. Rio, “What is the mechanism of soap film entrainment?”, Langmuir, 27 (22), 13406-13409, 2011.

B. Scheid, J. Delacotte, B. Dollet, E. Rio, F. Restagno, E. A. van Nierop, I. Cantat, D. Langevin and H. A. Stone, “The role of surface rheology in liquid film formation”, Eur. Phys. Lett., 90, 24002, 2010.

Foam Coarsening


A. Salonen, C. Gay, A. Maestro, W. Drenckhan, E. Rio, Arresting bubble coarsening: A model for stopping grain growth with interfacial elasticity, Eur. Phys. Lett., 2016.

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Foam Drainage


P. Yazhgur, E. Rio, F. Rouyer, F. Pigeonneau, A. Salonen, “Drainage in a rising foam.” Soft Matter, 12 (3), 905-913, 2016.

Foams stabilised by nanoparticles at the interface


E. Rio, W. Drenckhan, A. Salonen, D. Langevin, "Unusually stable Liquid Foams." Advances in Colloid and Interface Science, 205, 74-86, 2014.

L. R. Arriaga, W. Drenckhan, A. Salonen, J. A. Rodrigues, R. Iniguez-Palomares, E. Rio and D. Langevin , “On the long-term stability of foams stabilised by mixtures of nano-particles and oppositely charged short chain surfactants”, Soft Matter, 8, 11085, 2012.

J. A. Rodrigues, E. Rio, J. Bobroff, D. Langevin, W. Drenckhan, “Generation and manipulation of bubbles and foams stabilised by magnetic nanoparticles”, Coll. Sur. A, 384 (1-3), 408–416, 2011.

D. Y. Zang, E. Rio, G. Delon, D. Langevin, B. Wei, B. P. Binks, “Influence of the contact angle of silica nanoparticles at the air–water interface on the mechanical properties of the layers composed of these particles”, Molecular Physics, 109 (7-10), 2011.

D. Zang, E. Rio, D. Langevin, B. Wei, and B. P. Binks,, "Viscoelastic properties of silica nanoparticle monolayers at the air-water interface." Eur. Phys. J. E, 31 (2): 125-134, 2010.

A. Stocco, W. Drenckhan, E. Rio, D. Langevin and B. P. Binks, “Particle-stabilised foams: an interfacial study”, Soft Matter, 5, 2215-2222, 2009.

A. Cervantes Martinez, E. Rio, G. Delon, A. Saint-Jalmes, D. Langevin and B.P. Binks, “On the origin of the remarkable stability of aqueous foams stabilised by nanoparticles: Link with microscopic surface properties”, Soft Matter, 4, 1531 – 1535, 2008.

Liquid Fraction profile in a foam


A. Maestro, W. Drenckhan, E. Rio, R. Hohler, “Liquid dispersions under gravity: volume fraction profile and osmotic pressure”, Soft Matter, 9 (8), 2531-2540, 2013.

Foams stabilised by particles contained in the bulk


A. Salonen, R. Lhermerout, E. Rio, D. Langevin and A. Saint-Jalmes, "Dual gas and oil dispersions in water: production and stability of foamulsion." Soft Matter, 8, 699-706, 2012.

D. Varade, D. Carriere, L. R. Arriaga, A.-L. Fameau, E. Rio, D. Langevin and W. Drenckhan, "On the origin of the stability of foams made from catanionic surfactant mixtures", Soft Matter, 7(14): 6557-6570, 2011.

Modelisation of soap flow in trees


K. H. Jensen, E. Rio, R. Hansen, C. Clanet, T. Bohr, ”Osmotically driven pipe flows and their relation to sugar transport in plants, J. Fluid, Mech., 636, 371-396, 2010.

Drying of colloidal dispoersions


E. Rio, A. Daerr, F. Lequeux, L. Limat, "Moving contact lines of colloidal suspension in presence of drying", Langmuir, 22, 3186, 2006.

Sliding Drops


E. Rio, A. Daerr, B. Andreotti, L. Limat, "Boundary Conditions in the Vicinity of a Dynamic Contact Line: Experimental Investigation of Viscous Drops Sliding Down an Inclined Plane", Phys. Rev. Lett., 94, 024503, 2005.

J. Snoeijer, E. Rio, N. Le Grand, L. Limat, "Self-similar flow and contact line geometry at the rear of cornered drops", Physic of Fluids, 17, 072101, 2005.

Dry patches in flowing films


E. Rio, L. Limat, "Wetting hysteresis of a dry patch left inside a flowing film", Phys. Fluids., 18, 032102, 2006.

E. Rio, A. Daerr, L. Limat, "Probing with a laser sheet the contact angle distribution along a contact line", J. Coll. Int. Sc., 269, 164-170, 2004.


MANUSCRIPTS


PhD Thesis Habilitation
FORMER PhD STUDENTS


Emilie Forel
Lorène Champougny

Thesis
Laurie Saulnier


Thesis
Jérome Delacotte
Alfredo Cervantes
Du Yang Zang

Bibliography

2018

2017

2016



  • L. Champougny, M. Roché, W. Drenckhan, and E. Rio, “Life and Death of not so "bare" bubbles”, Soft Matter, vol. 12, p. 5276–5284, 2016.


  • E. Forel, E. Rio, M. Schneider, S. Beguin, D. Weaire, S. Hutzler, and W. Drenckhan, “Volume and surface fraction of liquid dispersions”, Soft Matter, vol. 12, no. 38, p. 8025–8029, 2016.

  • S. Jones, E. Rio, C. Cazeneuve, L. Nicolas-Morgantini, F. Restagno, and G. S. Luengo, “Tribological influence of a liquid meniscus in human sebum cleaning”, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol. 498, p. 268-275, 2016.
    Abstract: The interaction of surfactants in solution with hydrophobic materials is at the root of the process of detergency. Lipid containing micelles are formed in solution, and through water rinsing, these structures are washed out from the surface. The presence of air in the solution and the formation of foam add complexity to the system due to the increased proportion of water interfaces in contact with the surface. The latter situation is more difficult to understand. In this work, we propose, as a first step, to explore the role of the interfaces in cleaning silicon wafers previously coated with a model lipid mixture representing human sebum has been investigated. It turns out that the presence of interfaces enhances the cleaning efficiency. The effect of altering the surface properties of the silicon wafer was also investigated and it was found that changing the contact angle of the wafer brought a very strong effect on the cleaning efficiency. (C) 2016 Elsevier B.V. All rights reserved.
    Tags: Detergency, Foam-oil interaction, Surface energy.


  • V. Miralles, E. Rio, and M. -caroline Jullien, “Soft Matter Investigating the role of a poorly soluble surfactant in a thermally driven 2D microfoam †”, Soft Matter, vol. 12, p. 7056–7062, 2016.


  • A. Salonen, C. Gay, A. Maestro, W. Drenckhan, and E. Rio, “Arresting bubble coarsening : A two-bubble experiment to investigate grain growth in the presence of surface elasticity”, European Physics Letters, vol. 116, p. 46005, 2016.

2015



  • L. Champougny, B. Scheid, F. Restagno, J. Vermant, and E. Rio, “Surfactant-induced rigidity of interfaces: a unified approach to free and dip-coated films”, SOFT MATTER, vol. 11, no. 14, p. 2758-2770, 2015.
    Abstract: The behavior of thin liquid films is known to be strongly affected by the presence of surfactants at the interfaces. The detailed mechanism by which the latter enhance film stability is still a matter of debate, in particular concerning the influence of surface elastic effects on the hydrodynamic boundary condition at the liquid/air interfaces. In the present work, “twin” hydrodynamic models neglecting surfactant transport to the interfaces are proposed to describe the coating of films onto a solid plate (Landau-Levich-Derjaguin configuration) as well as soap film pulling (Frankel configuration). Experimental data on the entrained film thickness in both configurations can be fitted very well using a single value of the surface elasticity, which is in good agreement with independent measurements by mean of surface expansion experiments in a Langmuir through. The analysis thus shows that soap films or dip coating experiments may be used to measure the surface elasticity of surfactant solutions in the insoluble limit, namely as long as the film generation dynamics is fast compared to the surfactant adsorption timescale.


  • L. Saulnier, W. Drenckhan, P. Larré, C. Anglade, D. Langevin, E. Janiaud, and E. Rio, “In situ measurement of the permeability of foam films using quasi-two-dimensional foams”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 473, p. 32–39, 2015.
  • P. Yazhgur, D. Langevin, H. Caps, V. Klein, E. Rio, and A. Salonen, “How antifoams act: a microgravity study”, npj Microgravity, vol. 1, p. 15004, 2015.


  • P. Yazhgur, E. Rio, F. Rouyer, F. Pigeonneau, and A. Salonen, “Drainage in a rising foam”, Soft Matter, vol. 12, p. 905–913, 2015.

2014


  • H. Caps, G. Delon, N. Vandewalle, R. M. Guillermic, O. Pitois, A. L. Biance, L. Saulnier, P. Yazhgur, E. Rio, A. Salonen, and D. Langevin, “Does water foam in microgravity?”, Europhysics News, vol. 45, no. 3, p. 22–25, 2014.
  • H. Caps, N. Vandewalle, A. Saint-jalmes, L. Saulnier, P. Yazhgur, E. Rio, A. Salonen, and D. Langevin, “How foams unstable on earth behave in mocrogravity?”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 457, p. 392–396, 2014.

  • A. Maestro, E. Rio, W. Drenckhan, D. Langevin, and A. Salonen, “Foams stabilised by mixtures of nanoparticles and oppositely charged surfactants: relationship between bubble shrinkage and foam coarsening.”, Soft matter, vol. 10, p. 6975–6983, 2014.
    Abstract: We have studied foams stabilised by surfactant-decorated nanoparticles adsorbed at the bubble surfaces. We show that the controlled compression of a single bubble allows one to understand the coarsening behavior of these foams. When bubbles are compressed, the particles become tightly packed in the surface layer. They lose their mobility, and the interface becomes solid-like when the jammed state is reached. Further compression leads to interfacial buckling characterised by crumpled surfaces. We find that the surface concentration of particles at which the jamming and the buckling transitions occur are independent of the surfactant concentration. This is a surprising feature. It suggests that the surfactants are mandatory to help the particles adsorb at the interface and that they change the equilibrium surface concentration of the decorated particles. But they do not affect the surface properties once the particles are adsorbed. We measured the compression elastic modulus of the surface in the jammed state and found it to be compatible with the Gibbs condition for which the spontaneous dissolution of bubbles is arrested. Due to this effect, the coarsening process of a foam composed of many close-packed bubbles occurs in two steps. In the first step, coarsening is slow and coalescence of the bigger bubbles is observed. In the second step, a number of very small bubbles remains, which exhibit crumpled surfaces and are stable over long times. This suggests that foam coarsening is arrested once the smallest bubbles become fully covered after the initial shrinking step.
  • E. Rio and A. - L. Biance, “Coalescence in liquid foams”, ChemPhysChem, vol. 15, no. 17, p. 3692–3707, 2014.


  • A. Salonen, W. Drenckhan, and E. Rio, “Interfacial dynamics in foams and emulsions”, Soft Matter, vol. 10, p. 6870–6872, 2014.

  • L. Saulnier, J. Boos, C. Stubenrauch, and E. Rio, “Comparison between generations of foams and single vertical films – single and mixed surfactant systems”, Soft Matter, vol. 10, no. 29, p. 5280, 2014.
    Abstract: The purpose of this article is to compare experiments carried out with single vertical foam films and with foams. We focus on the generation of films and foams and measure (i) the quantity of water entrained and (ii) the stability of the systems. The surfactants we used are C12E6, [small beta]-C12G2 and their 1 : 1 mixture because those systems are very well characterised in the literature and are known to stabilise foams with very different properties. We show that the quantity of water uptake in foams and single vertical films scales in the same way with the velocity of generation. However, the different surfactant solutions have different foamabilities, whereas the films they stabilise have exactly the same thickness. Moreover, the foamability of a C12E6 solution is much lower than that of a [small beta]-C12G2 solution or of a solution of the 1 : 1 mixture. This is due to the rapid rupture of the C12E6 foam films during foam generation. Surprisingly, the isolated films have exactly the same lifetime for all the surfactant solutions. We conclude that, though drawing a correlation between films and foams is tempting, the results obtained do not allow correlating of film and foam stability during the generation process. The only difference we observed between the single films stabilised by the different solutions is the stability of their respective black films. We thus suggest that the stability of black films during foam generation plays an important role which should be explored further in future work.

  • L. Saulnier, L. Champougny, G. Bastien, F. Restagno, D. Langevin, and E. Rio, “A study of generation and rupture of soap films”, SOFT MATTER, vol. 10, no. 16, p. 2899-2906, 2014.
    Abstract: What are the lifetime and maximum length of a soap film pulled at a velocity V out of a bath of soapy solution? This is the question we explore in this article by performing systematic film rupture experiments. We show that the lifetime and maximal length of the films are fairly reproducible and controlled only by hydrodynamics. For surfactants with high surface elastic modulus, we argue that the rupture is triggered by the expansion of a thinning zone at the top of the film. The length l(tz) of this zone expands with time at a velocity equal to V/2, which can be obtained by a balance between gravity and viscous forces. The film lifetime is then found to decrease with the pulling velocity V, which implies that the surface tension gradient along the film increases with V. This surface tension gradient is found to be surprisingly small. Finally, the lifetime of films stabilised by solutions with small surface elastic modulus turns out to be much shorter than the ones for films with rigid interfaces.

2013


  • A. Maestro, W. Drenckhan, E. Rio, and R. Höhler, “Liquid dispersions under gravity: volume fraction profile and osmotic pressure”, Soft Matter, vol. 9, no. 8, p. 2531, 2013.
    Abstract: Many physical properties of concentrated dispersions of immiscible fluids are captured by the concept of an osmotic pressure, which measures how much energy is required to deform the bubbles or drops upon compaction. This pressure has a strong impact on the flow and drainage behavior of dispersions. Nevertheless, theoretical models describing its variation with the volume fraction phi of the continuous phase are so far available only in the limits of low or high phi and experimental data are scarce. We report an experimental study of osmotic pressure in foams and emulsions, showing how the effects of phi, disorder, grain size, polydispersity and interfacial tension can all be captured by a single law which satisfies previously established theoretical constraints. Building on this result, we propose the first equation which accurately describes the variation of the volume fraction with the height of a fluid dispersion under gravity.
    Tags: COMPRESSED EMULSIONS, ELASTICITY, FLOWS, foams, HIGHLY CONCENTRATED EMULSIONS.

2012


  • J. Delacotte, L. Montel, F. Restagno, B. Scheid, B. Dollet, H. A. Stone, D. Langevin, and E. Rio, “Plate Coating: Influence of Concentrated Surfactants on the Film Thickness”, LANGMUIR, vol. 28, no. 8, p. 3821-3830, 2012.
    Abstract: We present a large range of experimental data concerning the influence of surfactants on the well-known Landau-Levich-Derjaguin experiment where a liquid film is generated by pulling a plate out of a bath. The thickness h of the film was measured as a function of the pulling velocity V for different kinds of surfactants (C12E6, which is a nonionic surfactant, and DeTAB and DTAB, which are ionic) and at various concentrations near and above the critical micellar concentration (cmc). We report the thickening factor alpha = h/h(LLD), where h(LLD) is the film thickness obtained without a surfactant effect, i.e., as for a pure fluid but with the same viscosity and surface tension as the surfactant solution, over a wide range of capillary numbers (Ca = eta V/gamma, with eta being the surfactant solution viscosity and gamma its surface tension) and identify three regimes: (i) at small Ca alpha is large due to confinement and surface elasticity (or Marangoni) effects, (ii) for increasing Ca there is an intermediate regime where alpha decreases as Ca increases, and (iii) at larger (but still small) Ca alpha is slightly higher than unity due to surface viscosity effects. In the case of nonionic surfactants, the second regime begins at a fixed Ca, independent of the surfactant concentration, while for ionic surfactants the transition depends on the concentration, which we suggest is probably due to the existence of an electrostatic barrier to surface adsorption. Control of the physical chemistry at the interface allowed us to elucidate the nature of the three regimes in terms of surface rheological properties.
  • L. Dominique and E. Rio, “Coalescence in Foams and Emulsions”, in Encyclopedia of surface and colloid sciences, Taylor & Francis, 2012.
  • B. Scheid, S. Dorbolo, L. R. Arriaga, and E. Rio, “Antibubble dynamics: The drainage of an air film with viscous interfaces”, Physical Review Letters, vol. 109, no. 26, 2012.
    Abstract: An antibubble is a spherical air film that is immersed in a surfactant mixture and drains under the action of hydrostatic pressure. A dynamical model of this film is proposed that accounts for the surface shear viscosity effects in the case of purely viscous interfaces, which applies for surfactants whose adsorption rate is much larger than advection rate and at a concentration much above the critical micelle concentration. Our model shows that the lifetime of the antibubbles in this case increases with surface shear viscosity, denoted ϵ, whose value is measured independently, all in agreement with experimental measurements. We also found that the critical thickness, hc, at film rupture due to van der Waals interactions slightly depends on the surface shear viscosity, namely hc∝ϵ1/6.


  • A. Testouri, L. R. Arriaga, C. Honorez, M. Ranft, J. Rodrigues, A. V. D. Net, A. Lecchi, A. Salonen, E. Rio, R. Guillermic, D. Langevin, and W. Drenckhan, “Generation of porous solids with well-controlled morphologies by combining foaming and flow chemistry on a Lab-on-a-Chip”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 413, p. 17–24, 2012.

2011



  • J. A. Rodrigues, E. Rio, J. Bobroff, D. Langevin, and W. Drenckhan, “Colloids and Surfaces A : Physicochemical and Engineering Aspects Generation and manipulation of bubbles and foams stabilised by magnetic nanoparticles”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 384, no. 1-3, p. 408–416, 2011.

  • A. Salonen, R. Lhermerout, E. Rio, D. Langevin, and A. Saint-Jalmes, “Dual gas and oil dispersions in water: production and stability of foamulsion”, Soft Matter, 2011.
    Abstract: In this study we have investigated mixtures of oil droplets and gas bubbles and show that the oil can have two very different roles, either suppressing foaming or stabilising the foam. We have foamed emulsions made from two different oils (rapeseed and dodecane). For both oils the requirement for the creation of foamulsions is the presence of surfactant above a certain critical threshold, independent of the concentration of oil present. Although the foamability is comparable, the stability of the foamed emulsions is very different for the two oils studied. Varying a few simple parameters gives access to a wide range of behaviours, indeed three different stability regimes are observed: a regime with rapid collapse (within a few minutes), a regime where the oil has no impact, and a regime of high stability. This last regime occurs at high oil fraction in the emulsion, and the strong slowing down of ageing processes is due to the confinement of packed oil droplets between bubbles. We thus show that a simple system consisting of surfactant, water, oil and gas is very versatile and can be controlled by choosing the appropriate physical chemical parameters.
    Attachment Version soumise 714.9 kb (source)
    Attachment Version soumise 714.9 kb (source)

  • L. Saulnier, F. Restagno, J. Delacotte, D. Langevin, and E. Rio, “What Is the Mechanism of Soap Film Entrainment?”, LANGMUIR, vol. 27, no. 22, p. 13406-13409, 2011.
    Abstract: Classical Frankel's law describes the formation of soap films and their evolution upon pulling, a model situation of film dynamics in foams (formation, rheology, and destabilization). With the purpose of relating film pulling to foam dynamics, we have built a new setup able to give an instantaneous measurement of film thickness, thus allowing us to determine film thickness profile during pulling. We found that only the lower part of the film is of uniform thickness and follows Frankel's law, provided the entrainment velocity is small. We show that this is due to confinement effects: there is not enough surfactant in the bulk to fully cover the newly created surfaces which results in immobile film surfaces. At large velocities, surfaces become mobile and then Frankel's law breaks down, leading to a faster drainage and thus to a nonstationary thickness at the bottom of the film. These findings should help in understanding the large dispersion of previous experimental data reported during the last 40 years and clarifying the pulling phenomenon of thin liquid films.

  • A. Stocco, E. Rio, B. P. Binks, and D. Langevin, “Aqueous foams stabilized solely by particles”, vol. 7, no. 4, p. 1260–1267, 2011.

  • N. Vandewalle, H. Caps, G. Delon, A. Saint-Jalmes, E. Rio, L. Saulnier, M. Adler, A. L. Biance, O. Pitois, and S. C. Addad, “Foam stability in microgravity”, in Journal of Physics: Conference Series, 2011, vol. 327, p. 12024.

  • D. Varade, D. Carriere, L. R. Arriaga, A. L. Fameau, E. Rio, D. Langevin, and W. Drenckhan, “On the origin of the stability of foams made from catanionic surfactant mixtures”, Soft Matter, vol. 7, no. 14, p. 6557–6570, 2011.
    Abstract: Using mixtures of the anionic myristic acid (C13COOH) and the cationic cetyl trimethylammonium chloride (C16TA+Cl-) in aqueous solutions at a 2 : 1 ratio, we show that the outstanding stability of foams generated from sufficiently concentrated "catanionic" surfactant mixtures can be explained by a synergy effect between two fundamentally different mechanisms. Applying a multi-scale approach, in which we link static and dynamic properties of the bulk solutions, isolated gas/liquid interfaces, thin liquid films and foams, we identify these two mechanisms to be as follows: firstly, cationic mixtures create tightly packed surfactant layers at gas/liquid interfaces, which are strongly viscoelastic and also confer high disjoining pressures when two interfaces are approaching each other to form a thin liquid film. Foams created with such kind of interfaces tend to be extremely stable against coalescence (film rupture) and coarsening (gas exchange). However, typical time scales to cover the interfaces are much longer than typical foaming times. This is why a second mechanism plays a key role, which is due to the presence of micron-sized catanionic vesicles in the foaming solution. The bilayers of these vesicles are in a gel-like state, therefore leading to nearly indestructible objects which act like elastic micro-spheres. At sufficiently high concentrations, these vesicles jam in the presence of the confinement between bubbles, slowing down the drainage of liquid during the initial foaming process and therefore providing time for the interfaces to be covered. Furthermore, the tightly packed vesicles strongly reduce bubble coalescence and gas transfer between bubbles.

  • D. Y. Zang, E. Rio, G. Delon, B. Wei, and D. Langevin, “Influence of the contact angle of silica nanoparticles at the air–water interface on the mechanical properties of the layers composed of these particles”, Molecular Physics, vol. 109, p. 7–10, 2011.
    Tags: Contact angle, foams, nanoparticle monolayers, surface rheology.

2010


  • J. Delacotte, E. Rio, F. Restagno, C. Uzuem, R. von Klitzing, and D. Langevin, “Viscosity of Polyelectrolytes Solutions in Nanofilms”, LANGMUIR, vol. 26, no. 11, p. 7819-7823, 2010.
    Abstract: We use a thin film pressure balance to probe the rheological properties of thin liquid films. These films are made from mixed aqueous solutions of surfactants and polyelectrolytes. They drain under applied pressure in a noncontinuous way due to a stratification process of the polyelectrolytes network. The stratification kinetics was studied for films stabilized by different surfactants. Using a theoretical model, it is possible to examine the effect of both the surfactant and the film thickness on the local dissipation. On one hand, it was observed that dissipation depends on the polyelectrolyte concentration only, regardless whether the surfactant is neutral or bears electric charges opposite to those of the polyelectrolyte. On the other hand, it was found that dissipation is stronger in thinner films.

  • B. Scheid, J. Delacotte, B. Dollet, E. Rio, F. Restagno, E. A. van Nierop, I. Cantat, D. Langevin, and H. A. Stone, “The role of surface rheology in liquid film formation”, EPL, vol. 90, no. 2, 2010.
    Abstract: The role of surface rheology in fundamental fluid dynamical systems, such as liquid coating flows and soap film formation, is poorly understood. We investigate the role of surface viscosity in the classical film-coating problem. We propose a theoretical model that predicts film thickening based on a purely surface-viscous theory. The theory is supported by a set of new experimental data that demonstrates slight thickening even at very high surfactant concentrations for which Marangoni effects are irrelevant. The model and experiments represent a new regime that has not been identified before. Copyright (C) EPLA, 2010


  • D. Zang, E. Rio, D. Langevin, B. Wei, and B. Binks, “Viscoelastic properties of silica nanoparticle monolayers at the air-water interface”, The European Physical Journal E: Soft Matter and Biological Physics, vol. 31, no. 2, p. 125–134, 2010.

2009


  • K. \a are H. Jensen, E. Rio, R. Hansen, C. Clanet, and T. Bohr, “Osmotically driven pipe flows and their relation to sugar transport in plants”, Journal of Fluid Mechanics, vol. 636, p. 371–396, 2009.
    Abstract: In plants, osmotically driven flows are believed to be responsible for translocation of sugar in the pipe-like phloem cell network, spanning the entire length of the plant – the so-called Münch mechanism. In this paper, we present an experimental and theoretical study of transient osmotically driven flows through pipes with semi-permeable walls. Our aim is to understand the dynamics and structure of a ‘sugar front', i.e. the transport and decay of a sudden loading of sugar in a water-filled pipe which is closed in both ends. In the limit of low axial resistance (valid in our experiments as well as in many cases in plants) we show that the equations of motion for the sugar concentration and the water velocity can be solved exactly by the method of characteristics, yielding the entire flow and concentration profile along the tube. The concentration front decays exponentially in agreement with the results of Eschrich, Evert & Young (Planta (Berl.), vol. 107, 1972, p. 279). In the opposite case of very narrow channels, we obtain an asymptotic solution for intermediate times showing a decay of the front velocity as M−1/3t−2/3 with time t and dimensionless number M ηκL2r−3 for tubes of length L, radius r, permeability κ and fluid viscosity η. The experiments (which are in the small M regime) are in good quantitative agreement with the theory. The applicability of our results to plants is discussed and it is shown that it is probable that the Münch mechanism can account only for the short distance transport of sugar in plants.

  • A. Stocco, W. Drenckhan, E. Rio, D. Langevin, and B. P. Binks, “Particle-stabilised foams: an interfacial study”, Soft Matter, vol. 5, no. 11, p. 2215–2222, 2009.
    Abstract: In an attempt to elucidate the remarkable stability of foams generated from dispersions of partially hydrophobic nanoparticles (fumed silica), we present investigations into the static and dilational properties of the gas-liquid interfaces of such dispersions. By relating the dynamic surface tension [gamma](t) and the dilational elasticity E measured using an oscillating bubble device, we confirm that the Gibbs stability criterion E \textgreater [gamma]/2 against foam coarsening is fulfilled. We complement these studies using ellipsometry and Brewster angle microscopy, which provide evidence for a pronounced adsorption barrier for the particles and a network-like structure in the interface at sufficiently high concentrations. We observe this structure also in freely suspended films drawn from the same particle dispersions.
    Note Note
    <p>10.1039/b901180c</p>

2008

2006


  • E. Rio and L. Limat, “Wetting hysteresis of a dry patch left inside a flowing film”, Physics of Fluids, vol. 032102, no. 18, p. 032102, 2006.
  • E. Rio, A. Daerr, F. Lequeux, and L. Limat, “Moving contact lines of a colloidal suspension in the presence of drying”, Langmuir, vol. 22, no. 7, p. 3186–3191, 2006.
    Abstract: This article presents the first experimental study of an advancing contact line for a colloidal suspension. A competition between the hydrodynamic flow due to the drop velocity and the drying is exhibited: drying accounts for particle agglomeration that pins the contact line whereas the liquid flow dilutes the agglomerated particles and allows the contact line to advance continuously. The dilution dominates at low concentration and high velocity, but at high concentration and low velocity, the contact line can be pinned by the particle agglomeration, which leads to a stick-slip motion of the contact line. The calculation of the critical speed splitting both regimes gives an order of magnitude comparable to that of experiments. Moreover, a model of agglomeration gives an estimation of both the size of the wrinkles formed during stick-slip and the force exerted by the wrinkle on the contact line.

2005

  • E. Rio, A. Daerr, B. Andreotti, and L. Limat, “Boundary conditions in the vicinity of a dynamic contact line: Experimental investigation of viscous drops sliding down an inclined plane”, Physical Review Letters, vol. 94, no. 2, 2005.
    Abstract: To probe the microscopic balance of forces close to a moving contact$\backslash$nline, the boundary conditions around viscous drops sliding down an$\backslash$ninclined plane are investigated. At first, the variation of the contact$\backslash$nangle as a function of the scale of analysis is discussed. The dynamic$\backslash$ncontact angle is measured at a scale of 6 μm all around sliding$\backslash$ndrops for different volumes and speeds. We show that it depends only$\backslash$non the capillary number based on the local liquid velocity, measured$\backslash$nby particle tracking. This velocity turns out to be normal to the$\backslash$ncontact line everywhere. It indirectly proves that, in comparison$\backslash$nwith the divergence involved in the normal direction, the viscous$\backslash$nstress is not balanced by intermolecular forces in the direction$\backslash$ntangential to the contact line, so that any motion in this last direction$\backslash$ngets damped.
  • J. H. Snoeijer, E. Rio, N. Le Grand, and L. Limat, “Self-similar flow and contact line geometry at the rear of cornered drops”, Physics of Fluids, vol. 17, no. 7, p. 1–12, 2005.
    Abstract: Partially wetting drops sliding down an inclined plane develop a "corner$\backslash$nsingularity" at the rear, consisting of two dynamic contact lines$\backslash$nthat intersect. We analyze the three-dimensional flow in the vicinity$\backslash$nof this singularity by exploring similarity solutions of the lubrication$\backslash$nequations. These predict a self-similar structure of the velocity$\backslash$nfield, in which the fluid velocity does not depend on the distance$\backslash$nto the corner tip; this is verified experimentally by particle image$\backslash$nvelocimetry. The paper then addresses the small-scale structure of$\backslash$nthe corner, at which the singularity is regularized by a nonzero$\backslash$nradius of curvature R of the contact line. Deriving the lubrication$\backslash$nequation up to the lowest order in 1/R, we show that contact line$\backslash$ncurvature postpones the destabilization of receding contact lines$\backslash$nto liquid deposition, and that 1/R increases dramatically close to$\backslash$nthe "pearling" instability. The general scenario is thus that sliding$\backslash$ndrops avoid a forced wetting transition by forming a corner of two$\backslash$ninclined contact lines, which is regularized by a rounded section$\backslash$nof rapidly decreasing size.

2004



  • E. Rio, A. Daerr, and L. Limat, “Probing with a laser sheet the contact angle distribution along a contact line”, Journal of Colloid and Interface Science, vol. 269, no. 1, p. 164–170, 2004.
    Abstract: An optical method for probing contact angle distribution along contact lines of any shape using a laser sheet is proposed. This method is applied to a dry patch formed inside a film flowing along an inclined plane, both liquid and solid being transparent. Falling normally to the plane, a laser sheet cuts the contact line and is moved along this line. Distortions of the sheet trace observed on a screen put below the plane allow us to extract the contact angle distribution and the local line inclination along the line. Our results show that the contact angle around a dry patch is nearly constant and equal to the static advancing angle, at least when the evolution of its shape is followed for increasing flow rates. This supports a model of dry patch shape recently proposed by Podgorski and co-workers. Preliminary results obtained for decreasing flow are also qualitatively observed.
    Tags: Contact angle, Dewetting, Film flows, Laser sheet, wetting.
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