Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Focus: Wetting on smooth and rough surfaces: From spreading to superhydrophobicity I

CPP 22.9: Vortrag

Mittwoch, 13. März 2013, 12:15–12:30, H34

Dynamic Measurement of the Force Required for Moving a Liquid Drop on a Solid Surface — •Dominik Pilat, Periklis Papadopoulos, David Schäffel, Doris Vollmer, Rüdiger Berger, and Hans-Jürgen Butt — Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany

A novel setup for direct measurement of the force needed to move a drop on a solid surface was developed. The forces were measured by means of a vertical deflectable capillary stuck in the drop. The drop adhesion force instrument (DAFI) allowed us to investigate the dynamic lateral adhesion force of water drops of 0.1 to 2 μL volume at defined velocities. On flat PDMS surfaces, the dynamic lateral adhesion force increases linearly with the diameter of the contact area of the solid liquid interface and linearly with the sliding velocity. We further investigated a 3D superhydrophobic pillar array. The depinning of the receding part of the rim of the drop occurred almost simultaneously for four to five pillars, giving rise to peaks in the lateral adhesion force. The spatial resolution of the lateral adhesion force, which is possible with the DAFI, is not only interesting for scientific applications, but also for industrial applications like quality control of surfaces made in large scale processes.