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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 22.4: Vortrag

Mittwoch, 13. März 2013, 10:30–10:45, H34

History-dependent dynamic receding contact angles of aqueous surfactant solution slugs flowing through polymeric capillaries — Manos Anyfantakis, Daniela Fell, Hans-Jürgen Butt, and •Günter K. Auernhammer — Max Planck Institute for Polymer Research, Mainz, D-55128, Germany

The time-dependent dewetting behavior of surfactant solution slugs which are forced to move in fluorinated ethylene propylene (FEP) micro-tubes was experimentally investigated. The dynamic receding contact angle at a given wetting velocity, measured by high-speed imaging of the receding menisci, was found to decrease as the solid-liquid contact time increased. Long-time kinetics of several hundred s led to a final state displaying a 0o dynamic receding contact angle. The receding contact angle kinetics was found to strongly depend on the slug velocity. Higher speeds led to a faster decrease in the receding contact angles. Qualitatively similar results were obtained for anionic (sodium dodecyl sulfate) and cationic (hexadecyltrimethylammonium bromide) aqueous surfactant solutions at concentrations below and equal to the corresponding critical micellar concentration. Employing a different hydrophobic surface (polycarbonate micro-tubes) led to an analogous dewetting behavior, presumably indicating a generic effect for hydrophobic solid surfaces. This history effect was absent in simple liquids (2-propanol, water), where the dynamic receding contact angle does not depend on the contact time.

M. Anyfantakis et al., Chem. Lett. 2012, 41, 1232