Pinning of the Triple Line

If instead of imposing on the line a certain displacement velocity, we exert on it a macroscopic force per unit length given by 

We find that break off is impossible to trigger below a threshold force. The line remains fixed for angles 6 Or. 

We proceed next to discuss the energy associated with the distortion of the triple line. 

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The roughness of solid surfaces affects wetting owing to two different effects the first is the fact that the actual surface area is increased and the second is pinning of the triple line by sharp edges. 

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