Contact-angle hysteresis in solid-on-solid wetting - art. no. 011601

The spreading of an elastic adhesive sphere on a substrate is calculated us ing continuum elasticity theory and the van der Waals interaction between t he solid surfaces. The deformation and contact area are obtained self-consi stently as a function of lend. Hysteresis is demonstrated between the loadi ng and the unloading cycles: the receding contact angle exceeds the advanci ng one. In addition, for a given deformation (flattening), or fur a given a pplied load, the receding contact area exceeds the advancing one. This none quilibrium phenomenon is velocity dependent and in accord with experiments on adhesion and crack propagation.