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Surface Tension Regularises the Crack Singularity of Adhesive Contacts
Recent studies revealed a profound connection between “liquid wetting” and “solid adhesion” : both emerge as a limiting case for adhesion between sticky, elastic bodies. Here we address the unification of wetting and adhesion on the level of the contact mechanics. We first show that soft elastic bodies can exhibit a wetting angle, which just like liquids is governed by Young’s law. For very stiff materials it is then shown how the Young’s angle condition leads to a thin boundary layer near the edge of the contact — we derive a similarity solution for the boundary layer, from which the classical JKR law is recovered. The analysis reveals how surface tension provides a regularisation of the famous crack-like singularity at the edge of adhesive contacts.