Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.14: Poster

Freitag, 4. März 2005, 17:15–19:00, Poster TU D

Monodisperse Emulsions Confined to Channels — •Magdalena Ulmeanu, Dmytro Melenevsky, Stephan Herminghaus, and Ralf Seemann — MPI for Dynamics and Self-Organization, D-37073 Göttingen

The controlled manipulation of liquid compartments within microchannels has been termed digital microfluidics. The crucial issue here is the interplay of the size of the liquid compartments, with the lateral dimension of the channels. This enables comprehensive control of microfluidic processing like sorting, mixing, reacting, separating, provided all liquid compartments are equally sized. Emulsion droplets with diameter in between 2 and 20 microns provide suitable compartments for very small quantities of solvents or reagents. We therefore study several techniques for the preparation of highly stable and monodisperse microemulsions. Subsequent to the preparation, the continuous phase of the emulsion is reduced. The resulting gel emulsion is analogous to a dry foam, why we tend to term it spumo-emulsion (lat. spuma = foam). It exhibits a variety of transitions in its topology upon interaction with an externally provided (temporally variable) geometric constraint. We exploit the interaction of the internal length scale of these compartmented fluids with the lateral dimension of micro channels. In addition, we study the formation of 2D and 3D emulsion crystals by mixing droplets with two distinct diameters with a certain size ratio, which may lead to a novel type of chemical reaction setup and new materials.