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O: Fachverband Oberflächenphysik

O 44: Scanning Probe Methods I

O 44.9: Vortrag

Mittwoch, 13. März 2013, 12:30–12:45, H33

Capillary forces between a rigid sphere and an elastic half -space: the role of Young’s modulus and equilibrium vapor adsorption — Marjan Zakerin¹, •Michael Kappl¹, Ellen Backus¹, Hans-Jürgen Butt¹, and Friedhelm Schönfeld² — ¹Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz — ²Hochschule RheinMain, Faculty of Engineering, Am Brückweg 10, 65428 Rüsselsheim

Capillary adhesion of microparticles to a deformable substrate was analytically calculated, simulated by finite element simulations and measured with an atomic force microscope. The effects of elastic deformation and liquid adsorption were analyzed. Using an atomic force microscope, we measured the force between a silica bead of 2 µm radius and a silicon wafer (Young’s modulus E = 170 GPa) and polydimethylsiloxane (PDMS, E = 1 MPa) in the presence of ethanol at different vapor pressures. Adhesion forces on soft surface were much stronger than on rigid samples. In order to fully explain the experimental results, the previous developed theory by Butt et al. (1) was extended to take into account vapor adsorption of ethanol. Calculations were compared to results of finite element (FEM) simulations taking the detailed deformation of the elastic support close the meniscus explicitly into account.

(1) H.-J. Butt, W. J. P. Barnes, A. del Campo, M. Kappl and F. Schönfeld, Soft Matter, 2010, 6, 5930