Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 39: Wetting, Microfluidics and Confined Liquids I (joint session CPP/DY)

DY 39.2: Vortrag

Mittwoch, 14. März 2018, 10:00–10:15, C 264

How drops start sliding over solid surfaces — Doris Vollmer¹, Nan Gao^1,2, Florian Geyer¹, Dominik Pilat¹, Sanghyuk Wooh¹, Hans-Jürgen Butt¹, and •Rüdiger Berger¹ — ¹Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany — ²Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China

We report that the lateral adhesion force between a liquid drop and a solid can be divided into a static and a kinetic regime. This striking analogy with solid-solid friction is a generic phenomenon that holds for liquids [1]. We have investigated the lateral adhesion forces of liquids of different polarities and surface tensions on smooth, rough and structured surfaces. The lateral adhesion forces were measured with a home build instrument [2] and calculated by the occurring changes of the rear and the front of the drop, its changes in drop widths and the liquid-air surface tension. Our studies indicate that the lateral adhesion force is dominated by contact line friction and interfacial friction only plays a minor role. Finally, the lateral adhesion force measurements can provide quantitative information on the homogeneity or cleanliness of surfaces.

References:

[1] N. Gao, F. Geyer, D.W. Pilat, S. Wooh, D. Vollmer, H.-J. Butt, R. Berger, Nature Physics (2017), doi: 10.1038/NPHYS4305

[2] D. W. Pilat, P. Papadopoulos, D. Schäffel, D. Vollmer, R. Berger, H.-J. Butt, Langmuir 28, 16812-16820(2012), doi 10.1021/la3041067