Monodispersed water-in-oil emulsion generation in electric field

Emulsification involves dispersing one liquid into another immiscible liquid, with water-in-oil emulsions being particularly valuable in applications like biological, pharmaceutical, cosmetics, and food industries. Large-scale high-shear mixers are commonly used for emulsification, but small-volume and more controllable microfluidic methods are preferred when uniform emulsions are needed. We present an electrical method to generate emulsions using simple parallel plates, a device similar to electromicrofluidic (EMF) platform that offers integrability and portability. By applying a moderate electric field, a water droplet in an oil environment will spread and begin to eject small droplets along its edge. By controlling the applied electric field, emulsions with uniform and adjustable volume can be produced. Key parameters like interfacial tension, frequency and amplitude of the applied electrical signal are characterized. The developed emulsification method offers a simpler way to generate water-in-oil emulsions and opens up new possibilities for industrial applications.