Marangoni flows induced by soluble surfactants
In a nutshell
A solution of soluble surfactants is injected into pure water. The surface flows observed are a macroscopic manifestation of the solution’s surface rheology properties.
A few details
The injected solution contains surfactants and small drops of oil. The latter allow us to visualize the flow by reflecting the light (the experiment is illuminated from above).
The concentration of surfactants is high at the point of injection, and decreases with distance. This induces a surface tension gradient, giving rise to a surface flow. This is known as the Marangoni effect. The black disk we see corresponds to this surface flow. The lower the solubility of the surfactants, the wider the disk. At the edges of the disk, flow stoppage leads to the generation of surface vortex pairs, arranged in a regular pattern along the flow contour.
The flow observed is highly dependent on surfactant properties, and this experiment could serve as a quality control tool when looking for biobased alternatives to petrochemical surfactants.
References
about the black disk: M Roché, Z Li, IM Griffiths, S Le Roux, I Cantat, A Saint-Jalmes, H A Stone, “Marangoni flow of soluble amphiphiles”, Physical review letters (2014)
about the vortex: Gabriel Le Doudic (2022), “Écoulements solutocapillaires en présence d’échange interface-volume : génération de vorticité interfaciale et propulsion”
Internship/PhD on Hydrogels for adsorption of toxic metals
Proposal for master internship/PhD Hydrogels and composites with optimal efficiency and minimal environmental impact for adsorption of toxic metals The increasing demand for water due to technology and industrial activity has led to the use of hydrogels to treat...
Postdoc on the acoustics of membrane materials
As part of the Membranes project, the MSC laboratory is carrying out experimental research into the acoustic properties of membrane media, i.e. media whose internal structure contains thin layers of materials that can provide an original elastic response [1]. Examples...
Postdoc on heterogenous cavitation
We are looking for a post-doc to join our research team and perform experiment on heterogeneous cavitation to explore the origin of cavitation nuclei. The apparition of macroscopic bubbles inside a liquid either by boiling when temperature increases, from cavitation...
18-month post-doctoral fellowship on pulmonary surfactant
Structure and rheology of pulmonary surfactantResearch The INHALE project, funded by the French National Research Agency (ANR), seeks to investigate the viability of surfactant replacement therapy in adults afflicted with respiratory disorders. Pulmonary surfactant is...
M2/Thesis 2023-2024 internship proposal
Nuclear mechanics as a diagnostic and therapeutic target for glioblastoma Glioblastomas (GBMs) are the most lethal primary brain tumours. The absence of effective therapies is mainly due to tumour invasion and to the resistance of invading cells to treatments such as...
PhD defense. 05/11/2024, Lorijn van der Spek: “Application of mechanical and geometrical constraints of muscle cells to promote differentiation at different scales”
Tuesday, November 5th, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75013 Paris. PhD defense of Lorijn van der Spek Application of mechanical and geometrical constraints of muscle cells to promote differentiation at different scales Supervised by Myriam...