We have explored the contact line dynamics on superhydrophobic surfaces. Using two complementary geometries (a millimetric sessile drop and a centimetric capillary bridge), we have measured the dynamic receding contact angle of water on surfaces composed of micropillar arrays for velocities spanning over five decades. We have also studied the effect of pillar fraction and compared the results to smooth surfaces with the same chemical nature and also to similar systems reported in the literature. We show that introducing surface textures in the form of micropillar arrays significantly decreases the dependency of the contact angle on the contact line speed compared to a smooth surface, and this velocity dependency also decreases with decreasing surface fraction of micropillars. Interestingly, we show that the exact texturation of the surface does not play a fundamental role in the angle-velocity relationships as long as microtextures present the same type of periodic pattern (pillar arrays or microgrids). These results are interpreted in terms of viscous friction reduction on superhydrophobic surfaces, shedding light on the underlying mechanisms governing their unique dynamic behavior.

Close

PrevNext

View figure in article

• Interfacial flows
• Surface & interfacial phenomena