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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session 2
CPP 37.16: Poster
Wednesday, April 2, 2014, 15:00–19:00, P3
Depinning mechanism of a droplet contact line on a superhydrophobic surface — •Marco Rivetti1,2, Anaïs Gauthier1, Jérémie Teisseire1, and Etienne Barthel1 — 1Surface du Verre et Interfaces, UMR 125 CNRS & Saint-Gobain — 2Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany
It has been demonstrated recently that water droplets on superhydrphobic surfaces may exhibit a strong contact angle hysteresis. Nature offers beautiful examples of both slippery - the lotus leaf - and adhesive - the red rose petal - superhydrophobic surfaces. Several approaches exist in the literature to explain the hysteresis, but most of the models predict the advancing and receding contact angles only under specific hypothesis (i.e. perfect knowledge of the shape of the contact line, given geometry of the surface texture...) In this work we show that the receding motion of the contact line on a textured surface is mediated by the propagation of kinks (step-like defects) all along the perimeter of the drop [1]. We detail the dynamics of this mechanism, and show how the displacement of the contact line and the value of the receding contact angle are affected by the presence of kinks. Our results involve both experiments conducted with water droplets on glass superhydrophobic surfaces and numerical simulations performed with Surface Evolver. We explore the potential of this new concept by assessing the impact of lattice type and texture motive on contact angle hysteresis.
[1] A. Gauthier et al., Phys. Rev. Lett., 110, 046101 (2013)