Area-selective microplasma treatment in microfluidic channels for novel fluid phase separators

Differences in surface tensions of individual fluid phases in multiphase mixtures can be utilized to achieve a phase separation. A new fabrication method for a microfluidic phase separator combines micropatterning methods with atmospheric-pressure plasma-based surface coating, allowing an inexpensive manufacturing and, if required upscaling by numbering-up. Of particular importance for the functioning of the novel Y-shaped separator are coatings with different surface free energies on opposite surfaces in the divergence zone of the main channel and in the two diverting channels. This paper presents the principle of the method and first results regarding the coatings and applications.