Emulsion droplet formation in a flow-focusing microfluidic device allows for the creation of highly monodisperse drops whose volumes are in the nano- to picoliter scale. Each droplet can be considered as an individual chemical reactor. The introduction of polymer or particle precursors as the dispersed phase in droplet-based microfluidics presents a unique approach to particle synthesis.

The development of novel non-ionic fluorosurfactants allows for using fluorocarbon oils as a water-free continuous emulsion phase. Fluorocarbon based emulsions allow for a simple, versatile, and straight forward method for the templated synthesis of particles that in conventional systems require multiple processing steps or may not be made at all.

The promises of this approach are exemplified by the suspension polymerization of polyurethanes (PU), in which the liquid precursor is emulsified into droplets in a microfluidic device that are then converted into polymer particles. The droplet stability against coalescence upon removal of the continuous phase by evaporation confirms the formation of solid PU particles. This proves that the water-free environment of fluorocarbon based emulsions allows for high conversion. Monodisperse, cross-linked, and fluorescently labeled PU-latexes with controllable mesh size have been produced through microfluidic emulsification in a simple one-step process.

The ability to control dispersed phase chemicals and the surrounding continuous phase within a flow-focusing microfluidic device facilitates the synthesis of a variety of monodisperse microsphere particles. Potential synthesis includes silica nano-particles, silica gels with highly ordered nano-structures, and materials which must by synthesized in an anhydrous environment.