Electrohydrodynamic generation and transport of a single or multiple droplets of aqueous two-phase system in microfluidic device

Abstract

We report the electrohydrodynamic generation and transport of droplets in an aqueous two-phase system that consists of tetrabutylammonium bromide (TBAB) and ammonium sulfate (AS). A single droplet and multiple droplets were generated by the application of d.c. electric pulse across the liquid-liquid interface of two aqueous phase laminar flows. Shear force of the continuous phase, electrophoretic attraction of the dispersed phase to an electrode and interfacial tension of the dispersed phase stream were combined to generate droplets. Movement of the droplets in the microfluidic channels was manipulated, directing the droplets of specific number into desired part of the device from the sequential flow of droplets by applying the programmed d.c. electric pulse synchronized with the droplet frequency.