Pinning of the triple contact line. When the liquid is pinned on a sharp edge, the edge angle can be higher than the advancing contact angle.

Contexts in source publication

Context 1

... that the liquid will recede if its contact angle is smaller than the receding angle θ r and will advance if higher than the advancing angle θ a . The plates are de- scribed by two surfaces -one horizontal in contact with the bridge, the other nearly vertical defining the edge -on which receding and advancing angles are considered (as shown in Fig. 2 for the bottom plate). In this case, the liquid will recede if the contact angle with the horizontal surface is smaller than θ r , and will advance only if the contact angle on the edge surface is higher than θ a . Considering the horizontal plane as reference, the liquid will remain as long as the contact is between θ r and θ m Fig. ...

Context 2

... shown in Fig. 2 for the bottom plate). In this case, the liquid will recede if the contact angle with the horizontal surface is smaller than θ r , and will advance only if the contact angle on the edge surface is higher than θ a . Considering the horizontal plane as reference, the liquid will remain as long as the contact is between θ r and θ m Fig. 2. Moreover, liquid pinning simplifies the problem because, by avoiding the triple contact line motion, the no slip condition ...