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Années 2008-2011

Nom Laboratoire : Laboratoire de Physique des Solides

Code d’identification CNRS : UMR8502

Nom du responsable de la thèse : Dominique Langevin et Emmanuelle RIO

e-mail : et téléphone : 01 69 15 69 60

Lieu du stage : LPS, bat 510, Orsay

Titre : Mousses liquides en microgravité

Liquid foams are complex arrangement of discrete gas bubbles, which are separated by a continuous network of thin liquid films. These films need to be stabilised against rupture by surface active agents, which are molecules/objects that energetically prefer to gather at the gas/liquid interfaces.

Liquid foams occur in many domains in everyday life and industrial applications, where they are often wanted (food foams, cleaning foams, fire fighting foams, etc.), but just as often they are a nuisance (many industrial liquid processing routes, dishwasher). From both perspectives, it is very important to understand what controls the stability of these foams

Gravity plays an important role in de-stabilising foams, as it drains liquid out from between the bubbles. To isolate this influence from that of the surface active agents, our group is in the process of preparing micro-gravity experiments for the ISS (International Space Station) in conjunction with other international groups, ESA (European Space Agency) and NASA.

Thesis project description

At the heart of the thesis will be investigations of a wide range of surface active agents (soap molecules, polymers, proteins, liquid crystals, nano-particles, nano-discs…). Some of them indeed allow creating very strange foams (for example super stable foams lasting months). The goal of the project is understand and control these strange properties.

Within this project the PhD student who will have the unique opportunity to be directly involved in preparing and analysing micro-gravity experiments conducted on the ISS. These activities will be paralleled by experiments on the ground in which the interfacial properties of the foams will be related to their overall stability. Foams with well-controllable bubble sizes will be generated using micro-fluidic flow focussing techniques, and their stability will be investigated using techniques such as light scattering and electrical conductivity probing. The surfaces will also be investigated with techniques such as video-microscopy, wave propagation, oscillating drops or oscillating disc.

Important skills for the project

• Good experimental and technical skills • Organisational skill (preparing missions on parabolic flights and ISS) • Good English skills (written and oral)

Collaborative partners on the project

• D. Durian, University of Pennsylvania,, USA • D. Weaire, Trinity College Dublin, Ireland • R. Hoehler, University of Marne-la-Vallee, France • A. Saint-Jalmes, University of Rennes, France • N. Vandewalle, Université de Liège Belgique • Lead company : ASTRIUM, Germany

Web sites

The project : http://spaceflightsystems.grc.nasa....

The lab :

The group :