Interface Fragmentation via Horizontal Vibration: A Pathway to Scalable Monodisperse Emulsification

TL;DR

This paper introduces a scalable method for creating uniform micro-emulsions using horizontal vibration to excite Faraday waves, with theoretical and experimental insights into droplet formation.

Contribution

The study demonstrates a novel, scalable technique for monodisperse emulsification leveraging interface fragmentation via horizontal vibration and provides a theoretical model for droplet breakup.

Findings

Droplet size can be tuned by adjusting forcing parameters.

Critical acceleration for wave breakup scales as N^{-1/2} ω^{3/2}.

Number of droplets per cycle is proportional to container width.

Abstract

We present a scalable method for producing monodisperse micro-scale emulsions in a rectangular container holding two stably stratified layers of immiscible liquids by applying horizontal vibration. This setup enables the excitation of a single line of ordered Faraday waves along each end wall when viscous forces dominate interfacial dynamics. Our experiments and theoretical modelling show that the critical non-dimensional acceleration for the breakup of the wave tips in a regular array of droplets scales as $N^{-1/2} \omega^{*3/2}$, where $N$ is the kinematic viscosity ratio and $\omega^{*}$ is the frequency of forcing on the viscous-capillary scale. The droplet diameter can be easily tuned by varying the forcing parameters, and the number of droplets generated per cycle is proportional to the width of the container.