USING VIBRATIONAL NOISE TO PROBE ENERGY BARRIERS PRODUCING CONTACT-ANGLE HYSTERESIS

We measure the macroscopic capillary rise height of water on a chemica lly heterogeneous solid surface in the presence of vibrational noise. The amount of relaxation of the macroscopic contact angle depends on t he mechanical characteristics as well as the energy of the vibrations. The macroscopic recede and advance contact angles are functions of th e vibration level. Large enough vibration levels mitigate hysteresis. Microscopic contact line configurations depend strongly on microscopic wettability variation on the solid surface. Our study has implication s for contact angle measurements in normal vibration environments and for the retention of drops on inclined surfaces.