Triple line depinning criteria of planar and axisymmetric drops.*

Precise quantitative criteria predicting triple lines depinning are scarce. In order to find the, we have studied planar and axisymmetric layers and drops pinned at a sharp edges with apparent contact angle θ₀. Equilibrium is compatible with a fan of angles θ₀ bracketed by the equilibrium contact angles of the both flanks of the edge, so the triple line could remain pinned as long as θ₀ is within this fan. We find, however, critical depinning advancing θ_0a and receding θ_0r contact angles, which occur as subcritical saddle-node bifurcations with no equilibrium solutions beyond a critical suitably defined Bond number.