Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: Poster: Wetting, Micro and nanofluidics
CPP 21.9: Poster
Mittwoch, 28. März 2012, 11:00–13:00, Poster A
Forced wetting of simple and complex fluids in horizontal capillaries — •Manos Anyfantakis1, Günter K. Auernhammer1, Daniela Fell1,2, Mohammad A. Dadfar1, and Hans-Jürgen Butt1,2 — 1Max Planck Institute for Polymer Research — 2Center of Smart Interfaces, Technical University of Darmstadt
Investigation of the physics governing the dynamic wetting of various liquids in cylindrical capillaries is of profound interest in numerous practical applications, such as microfluidic devices, oil extraction, and printing technologies as well as various medical applications. Additionally to spontaneous wetting of microchannels, forced capillary wetting could provide a straightforward way to systematically address questions in dynamic wetting of simple and complex fluids. Here, we describe a simple method, which allows for the simultaneous measurement of both the advancing and the receding contact angles of moving liquid slugs.
The experimental setup consists of three main parts: the liquid reservoir, the glass capillary and a microscope equipped with a fast camera, which is used to image the moving liquid slugs. The driving force for liquid motion is the gravity induced pressure difference between the reservoir and the microscope stage. The advancing/receding contact angles are determined either by placing the local tangent to the triple line-liquid-gas interface or by fitting the meniscus shape. Experimental results regarding dynamic wetting/dewetting of surfactant solutions in capillaries of different wettabilities, in a broad speed range, are as well as challenges and further possibilities of the method are discussed.