Coarsening transitions of wet liquid foams under microgravity conditions

We have recently published an article in Soft Matter to report foam coarsening studies which were performed in the International Space Station (ISS) to suppress drainage due to gravity. Foams and bubbly liquids with controlled liquid fractions between
15 and 50% were investigated. We determined the coarsening rates for the driest foams and the bubbly liquids, which are in close agreement with theoretical predictions. We observe a sharp cross-over between the respective laws at a critical liquid fraction. At liquid fractions beyond this transition, neighboring bubbles are no longer all in contact, like at a jamming transition. Remarkably, the liquid fraction measured is significantly larger than the random close packing volume fraction of the bubbles, which was determined independently. We attribute the differences to a weakly adhesive bubble interaction that we have studied in complementary ground-based
experiments.