Triple emulsion droplets formation in cross-flow microchannel under electrostatic field control

Abstract

In droplet microfluidics, electrostatic fields can be used to regulate droplet formation, but the understanding of multilayer emulsion droplet formation is still not comprehensive. This study presents a numerical simulation study on the flow of triple emulsion within a cross-flow microchannel by establishing a coupled model of the electrostatic field and phase field. And assesses the quality and mechanical analysis of droplets. The research findings indicate that the emulsion in the channel generates triple emulsion droplets through both dripping and jetting regime. When the electric field strength remains constant, the average core/shell eccentricity (ω_im-i) of the droplets generated by the dripping regime is 0.0366, and the average shell thickness (δ_s) can reach a maximum of 375.322 μm, indicating that the structure is more stable. And it was found that increasing the electric field strength enhances the internal velocity of the droplets, indicating that the circulation of its internal material accelerates. Electrostatic actuation accelerates triple emulsion formation and has an effect on droplet mono-dispersity and size, and results in thinner thickness triple emulsion. These research findings enhance the understanding of the droplet formation process in multilayer emulsions and provide a theoretical foundation for the microfluidic preparation of multi-component droplet.