Microfluidic phase separation

We present a technique of phase separation suitable for microfluidic systems. We demonstrate that efficient phase separation based on capillarity is possible within a microfluidic chip (using either microfabricated capillary channels or microfiltration membranes), allowing for extraction of the pure continuous or dispersed phases. We test the method extensively with oil/water mixtures. The technique works well with phase mixtures as well as with emulsions, allowing for analysis of the specific phase of interest downstream of the separation. As an example we implement a microfluidic visible light spectroscopy measurement on the oil extracted from an oil/water emulsion.