Controllable production of Janus ligaments by AC fields in a flow‑focusing junction

Abstract

We report the production of bicomponent Janus filaments of miscible aqueous fluids in a microfluidic electro-flow-focusing device under the action of an AC electric field. The production of liquid filaments can lead to the generation of microfibers by adding a subsequent process of polymerization. Janus microfibers are of paramount importance in biomedical applications such as tissue production on crimped scaffolds. We show that the filament length is a function of the frequency signal, voltage amplitude and of the viscosity and conductivity of the dispersed phase. In particular, Janus filaments with diameters ∼ 10 μm and longer than 1 mm are produced by AC voltages with frequencies below 150 kHz and a viscosity of the dispersed phase ∼ 10 cP.