My research is located at the interface between hydrodynamics with flow of complex fluids such as foams or polymer solutions, physical-chemistry of colloidal suspensions as well as continuum mechanics based on consolidating materials. These different topics address fundamental problems in Soft Condensed Matter Physics while maintaining a connection with applications.
PhD in Soft Matter, 2013
Université Pierre et Marie Curie
Accreditation to direct research (HDR), 2020
Two days lecture for PhD students from EDPIF.
Production of scientific images is ubiquitous in many scientific disciplines as they can capture phenomena in a broad range of lengthscales, from the stars to the atom. Therefore, skills in image processing can be advantageous to perform and automate image analysis. This lecture will have a tutorial/workshop format and will mainly focus on the library scikit-image. This course will be taught in English in case of non French speaking attendees.
In this Letter, we show that the shape of a freezing drop of water can be sensitive to the presence of impurities. We measure the tip angle of water drops frozen on a cold plate. The fine changes in tip angle are robustly captured by our image analysis method, which shows a deviation from that of pure water in solutions with salt (NaCl), polymer (PEG) and surfactant (TTAB) starting at concentrations of 10−6, 10−4 and 10−6 M respectively. The method could be adapted into a portable water purity tester, but the work also highlights the complexity of water freezing as it is influenced by trace concentrations of impurities.
Complex liquids flow is known to be drastically affected by the roughness condition at the interfaces. We combined stresses measurements and observations of the flow during the motion of different rough surfaces in dry liquid foams. We visually show that three distinct friction regimes exists: slippage, stick-slip motion, and anchored soap films. Our stress measurements are validated for slippage and anchored regimes based on existing models, and we propose a leverage rule to describe the stresses during the stick-slip regime. We find that the occurrence of the stick-slip or anchored regimes is controlled by the roughness factor, defined as the ratio between the size of the surface asperities and the radius of curvature of the Plateau borders.