Patterning microfluidic device wettability with spatially-controlled plasma oxidation

Microfluidic devices can form double emulsions with uniform properties, but require cumbersome fabrication steps to pattern their wettability. We demonstrate spatially-controlled plasma oxidation to create wettability patterns for forming double emulsions. Our method performs comparably to chemical techniques but is simpler, more reliable, and scalable to patterning large arrays of drop makers.