  Wetting of sessile bubbles on solid and liquid surfaces has been studied. A
model is presented for the contact angle of a sessile bubble based on a
modified Young equation - the experimental results agree with the model. A
hydrophilic surface results in a bubble contact angle of 90 deg whereas on a
superhydrophobic surface one observes 134 deg. For hydrophilic surfaces, the
bubble angle diminishes with bubble radius - whereas on a superhydrophobic
surface, the bubble angle increases. The size of the Plateau borders governs
the bubble contact angle - depending on the wetting of the surface.
