Adhesion of yield stress fluids

Quentin Barral (1) , Guillaume Ovarlez (2) , Xavier Chateau (2) , Jalila Boujlel (2) , Brooks Rabideau (1) , Philippe Coussot (3)

1 navier umr 8205 - Laboratoire Navier
2 Rhéophysique
3 Physique des milieux poreux

The different regimes of flow when separating two solid rough surfaces in contact via a layer of a simple yield stress fluid are identified. Generic scalings for the adhesion energy and for the geometrical characteristics of the final deposits (after separation) as a function of the initial aspect ratio of the sample are found. We show that there is a strong pinning effect which might be at the origin of an adhesion energy significantly larger (by a factor about 2) than that estimated from the lubrication theory. We also observe that the conditions of development of viscous fingering are not at all predicted by the conventional Saffman-Taylor instability theory taking into account the specific non-Newtonian character of the fluid. This again suggests that for pastes the pinning effect plays a significant stabilizing role.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Quentin Barral, Guillaume Ovarlez, Xavier Chateau, Jalila Boujlel, Brooks Rabideau, et al.. Adhesion of yield stress fluids. Soft Matter, 2010, 6, pp.1343-1351. ⟨hal-00541793⟩