Friction of foams on rough surfaces

François Boulogne – LPS, Saclay

From our daily experience of entraining foam when getting out of our bath raises the question of role of foam flows on rough solids. In this presentation, I will show that foam can exhibit a range of flow behaviors on textured surfaces. It includes anchoring, which is particularly useful for performing rheological measurements, stick-slip and perfect slippage. With a particular caution on the fabrication of the surfaces, we found a wetting transition, which modifies the foam footprint on the surface from straight to zigzag contacts; this transition will be rationalized with a simple model. Finally, I will demonstrate how we can create a SLIPS (Slippery Liquid Infused Porous Surface) suitable for foams, which leads to a reduction of friction compared to smooth surfaces.