Discrete microfluidics: manipulation of gel emulsions in confined geometries

• Applicants: Martin Brinkmann, Ph.D.; Professor Dr. Ralf Seemann
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 67909302

Microfluidics is usually concerned with single phase liquids transported along microchannels. In the present project, we will explore the possibilities of using instead a compartmented liquid consisting of an emulsion, where the continuous phase has a very small volume fraction. Such an emulsion is called gel-emulsion and is geometrically quite analogous to a foam, which exhibits a variety of transitions in its topology upon interaction with an externally provided (temporally variable) geometric constraint. The main issue here is the interplay of the size of the droplets, with the lateral dimension of the channels. The effective repulsive interaction between the droplets can be continuously tuned via the volume fraction of the dispersed phase. Furthermore, due to the absence of static friction, gel emulsions may serve as a macroscopic model system to study orderdisorder transitions in confining geometries.We want to explore the physical mechanisms involved in a controlled manipulation of the emulsion droplets by the channel geometry. This may be used to position, sort, exchange, compile and redistribute liquid compartments in a lab-on-chip application.

• DFG Programme: Research Grants