  The characterization of the wetting on superhydrophobic surfaces is rather
complex. Usual contact angle experiments are difficult to perform and the
lateral movement of droplets as well as the pinning at point defects on the
surface can disturb the measurements. Even if precise contact angle
measurements can be performed the information gain is limited if the surface is
heterogeneously wetted. This results in the possibility of two surfaces with
different roughness, different surface energy and thus different underlying
wetting mechanisms exhibiting the same contact angle. We introduce the
utilization of dynamic wetting experiments as an additional surface probe which
allows a better characterization of superhydrophobic surfaces. A theoretical
model is presented which describes the spreading of water jets on a
superhydrophobic surface and allows the determination of the wetted fraction of
a heterogeneously wetted superhydrophobic surface. The determined values for
the wetted fraction identify a common problem when building artificial super
hydrophobic surfaces and can fundamentally improve their understanding.
