Double emulsion generation and separation by microfluidic consecutive flow focusing

This article describes the first developments of a microfluidic circuit for the continuous generation of monodisperse polymersomes. The generation of these vesicles is made in a consecutive flow focusing cross-junctions structure from non miscible fluids. The device allows generating a stream of polymersomes in two steps. The breaking of a focused water flow creates first water droplets in a solution of diblock polymer and then the double emulsion is generated at the second constriction. This paper will describe microflabrication of the device and a study of the dynamics of droplets formation by high frame rate videomicroscopy. The work has been done on liposome in first steps and them with Pb-b-PEO block polymer in a second time. Finally the paper will decribe the addition of a separation structure for sorting generated vesicles by their size.