Effect of Roughness on Capillary Contact Shapes in Tangential Shear: Experiments

The paper analyzes the effect of roughness on the shape of contacts of a tangentially moving stainless steel indenter and a silicate glass substrate with a liquid drop in between. The analysis, covering two series of experiments with two indenter radii and five degrees of glass roughness (including smooth-glass), provides measurement data on the normal and tangential contact forces, images of the contacts, and time dependences of their area. In each case considered, the contact boundary at the front and back edge behaves differently with the result that the contact during tangential motion loses its symmetry about the indenter center.