Roughness of the Contact Line on a Disordered Substrate

Abstract

We present results from an experimental study on the wetting properties of superfluid helium-4 on a cesium substrate with random disorder. We have measured the roughness exponents of the contact line, and found that they are in agreement with theoretical predictions. Furthermore, we have observed a strong increase of the contact line fluctuations near the wetting transition; this temperature dependence is consistent with the theory.