Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster Session 2

CPP 37.29: Poster

Mittwoch, 2. April 2014, 15:00–19:00, P3

Characterisation of a novel splitting geometry for microdroplets — •Michael Moskopp, Michael Hein, Jean-Baptiste Fleury, and Ralf Seemann — Experimental Physics, Saarland University

For applications in droplet based microfluidics it is essential to manipulate individual droplets. Along with coalescence, sorting and mixing of their contents the splitting of droplets is a crucial basic operation. Besides its employment in practical applications the physical process of droplet pinch off is still not completely understood. The most straight forward way to split droplets is to use channel geometries where they normally break into two parts. We report a novel splitting geometry with a broad main channel which subdivides into three narrow split channels. Thus a droplet is forced to split into three smaller compartments of different volumes along its flow direction. For an experimental study of this geometry the droplet-length and -velocity and the width ratio of the split channels were varied. Several regimes of different splitting characteristics were observed for each channel geometry. At low drop velocities the breakup mechanism is dominated by surface tension and capillary driven relaxation. However at higher flow velocities this relaxation process is negligible. Thus, in this case the splitting can be explained by geometrically cutting the droplet. Understanding droplet splitting in different geometries is crucial for design of future applications.