Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Poster: Focus: Wetting on smooth and rough surfaces: From spreading to superhydrophobicity
CPP 30.7: Poster
Mittwoch, 13. März 2013, 16:30–18:30, Poster C
Drop impact on superamphiphobic surfaces — •Xu Deng1, Frank Schellenberg1, Periklis Papadopoulos1, Longquan Chen2, Maxime Paven1, Lena Mammen1, Jihua Zhang1, Doris Vollmer1, and Hans-Jürgen Butt1 — 1Max Planck Institute for Polymer Research, Mainz — 2Center of Smart Interfaces, Technical University Darmstadt
The spreading and retraction kinetics of liquid drops impacting on superamphiphobic,[1] i.e. superhydrophobic and superoleophobic, surfaces is studied by high speed video microscopy. To investigate the influence of interfacial tension and viscosity on spreading and retraction kinetics mixtures of ethanol-water and glycerin-water are chosen. The main findings are identical for both systems, including the dependence of the impact scenario on drops' Weber and Reynolds number. At low impact velocity the drops rebound, however, the contact time increases when approaching the pinning regime. Drop spreading is dominated by inertia, independent of whether a drop rebounds or pins on the surface. The retraction phase is split into two regimes: a fast inertia dominated retraction of the drop's contour, followed by a slow decrease of the drop's contact diameter for diameters below the initial diameter of the drop before impact. Impact causes partial penetration and pinning of the liquid in the coating, even though the drop rebounds completely.
[1] X. Deng, L. Mammen, H.-J. Butt, and D. Vollmer; Candle soot as a template for a transparent robust superamphiphobic coating, Science, 335 (2012), 67-70.