Laboratoire de Physique des Solides - UMR 8502

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François Boulogne

CNRS researcher — Chargé de recherche CNRS

Laboratoire de Physique des Solides
Bât. 510 - Campus d’Orsay
91405 Orsay Cedex

Phone: +33 (0)1 69 15 53 64
Office: 003, West wing

Current scientific interests in a nutshell

- Drop absorption and colloidal deposition on hydrogels
- Stress measurement of drying colloidal suspensions by the deformation of soft substrates
- Controlled evaporation of simple liquids
- Flow of liquid foams

To know more about me


  • G. Guyard, A. Vilquin, N. Sanson, S. Jouenne, F. Restagno, and J. D. McGraw, “Near-surface rheology and hydrodynamic boundary condition of semi-dilute polymer solutions”, Soft Matter, vol. 17, no. 14, p. 3765-3774, 2021.
    Abstract: Using evanescent wave microscopy to study near-surface, semi-dilute polymer solution flows provides simultaneous access to the mechanical behaviour of the liquid and the boundary condition at the interfaces. Our results highlight the importance of electrostatic interactions between the polymers and the bounding wall. , Understanding confined flows of complex fluids requires simultaneous access to the mechanical behaviour of the liquid and the boundary condition at the interfaces. Here, we use evanescent wave microscopy to investigate near-surface flows of semi-dilute, unentangled polyacrylamide solutions. By using both neutral and anionic polymers, we show that monomer charge plays a key role in confined polymer dynamics. For solutions in contact with glass, the neutral polymers display chain-sized adsorbed layers, while a shear-rate-dependent apparent slip length is observed for anionic polymer solutions. The slip lengths measured at all concentrations collapse onto a master curve when scaled using a simple two-layer depletion model with non-Newtonian viscosity. A transition from an apparent slip boundary condition to a chain-sized adsorption layer is moreover highlighted by screening the charge with additional salt in the anionic polymer solutions. We anticipate that our study will be a starting point for more complex studies relating the polymer dynamics at interfaces to their chemical and physical composition.

  • C. A. E. Hamlett, D. N. Boniface, A. Salonen, E. Rio, C. Perkins, A. Clark, S. Nyugen, and D. J. Fairhurst, “Blowing big bubbles”, Soft Matter, vol. 17, no. 9, p. 2404-2409, 2021.
    Abstract: The radius of blown soap bubbles is very sensitive to the normalised air speed (Weber number We), growing up to ten times the wand radius in the slow speed dripping mode and reducing to just double the wand radius in the high speed jetting mode. , Although street artists have the know-how to blow bubbles over one meter in length, the bubble width is typically determined by the size of the hoop, or wand they use. In this article we explore a regime in which, by blowing gently downwards, we generate bubbles with radii up to ten times larger than the wand. We observe the big bubbles at lowest air speeds, analogous to the dripping mode observed in droplet formation. We also explore the impact of the surfactant chosen to stabilize the bubbles. We are able to create bubbles of comparable size using either Fairy liquid, a commercially available detergent often used by street artists, or sodium dodecyl sulfate (SDS) solutions. The bubbles obtained from Fairy liquid detach from the wand and are stable for several seconds, however those from SDS tend to burst just before detachment.

  • D. Langevin, “Light scattering by liquid surfaces, new developments”, Advances in Colloid and Interface Science, vol. 289, p. 102368, 2021.

  • S. Mariot, M. Pasquet, V. Klein, F. Restagno, and E. Rio, “A new setup for giant soap films characterization”, The European Physical Journal E, vol. 44, no. 4, p. 52, 2021.

  • R. Marquez, L. Meza, J. G. Alvarado, J. Bullón, D. Langevin, A. M. Forgiarini, and J. ‐L. Salager, “Interfacial Rheology Measured with a Spinning Drop Interfacial Rheometer: Particularities in More Realistic Surfactant–Oil–Water Systems Close to Optimum Formulation at <span style="font-variant:small-caps;"> HLD <sub>N</sub> </span> = 0”, Journal of Surfactants and Detergents, p. jsde.12502, Apr. 2021.

  • J. Miguet, F. Rouyer, and E. Rio, “The Life of a Surface Bubble”, Molecules, vol. 26, no. 5, p. 1317, Mar. 2021.
    Abstract: Surface bubbles are present in many industrial processes and in nature, as well as in carbonated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play.

  • R. Srivastava, V. Bosc, F. Restagno, C. Tournier, P. Menut, I. Souchon, and V. Mathieu, “A new biomimetic set-up to understand the role of the kinematic, mechanical, and surface characteristics of the tongue in food oral tribological studies”, Food Hydrocolloids, vol. 115, p. 106602, 2021.





  • F. Boulogne, F. Ingremeau, and H. A. Stone, “Coffee-stain growth dynamics on dry and wet surfaces”, Journal of Physics: Condensed Matter, vol. 29, no. 7, p. 074001, 2017.
    Abstract: The drying of a drop containing particles often results in the accumulation of the particles at the contact line. In this work, we investigate the drying of an aqueous colloidal drop surrounded by a hydrogel that is also evaporating. We combine theoretical and experimental studies to understand how the surrounding vapor concentration affects the particle deposit during the constant radius evaporation mode. In addition to the common case of evaporation on an otherwise dry surface, we show that in a configuration where liquid is evaporating from a flat surface around the drop, the singularity of the evaporative flux at the contact line is suppressed and the drop evaporation is homogeneous. For both conditions, we derive the velocity field and we establish the temporal evolution of the number of particles accumulated at the contact line. We predict the growth dynamics of the stain and the drying timescales. Thus, dry and wet conditions are compared with experimental results and we highlight that only the dynamics is modified by the evaporation conditions, not the final accumulation at the contact line.
    Tags: evaporation.

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