title: Block-and-break generation of microdroplets with fixed volume.
abstract: We introduce a novel type of droplet generator that produces droplets of a volume set by the geometry of the droplet generator and not by the flow rates of the liquids. The generator consists of a classic T-junction with a bypass channel. This bypass directs the continuous fluid around the forming droplets, so that they can fill the space between the inlet of the dispersed phase and the exit of the bypass without breaking. Once filled, the dispersed phase blocks the exit of the bypass and is squeezed by the continuous fluid and broken off from the junction. We demonstrate the fixed-volume droplet generator for (i) the formation of monodisperse droplets from a source of varying flow rates, (ii) the formation of monodisperse droplets containing a gradation of solute concentration, and (iii) the parallel production of monodisperse droplets.
authors.affiliation: School of Engineering and Applied Sciences/Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA ; Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands.
authors.forename: Volkert
authors.initials: V
authors.lastname: van Steijn
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland ; Institute of Fundamental Technological Research, PAS, Pawinskiego 5B, 02-106 Warsaw, Poland.
authors.forename: Piotr M
authors.initials: PM
authors.lastname: Korczyk
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Derzsi
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, California Institute for Quantitative Biosciences, University of California, San Francisco, California 94158, USA.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Abate
authors.affiliation: School of Engineering and Applied Sciences/Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Weitz
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Garstecki