Electric field- induced Pinch-off of a migrating compound droplet in confined micro channel

TL;DR

This study investigates how electric fields influence the pinch-off dynamics of compound droplets in microchannels, revealing controllable modes and timings of droplet rupture through electric property adjustments.

Contribution

It introduces a detailed analysis of electric field effects on droplet pinch-off modes and timings, providing a method to control droplet morphology in microfluidic systems.

Findings

Electric field strength affects droplet eccentricity and thinning kinetics.

Different pinch-off modes can be achieved by altering electric properties.

Electric control modifies pinch-off timing and location.

Abstract

The present study looks into the pinch-off dynamics of a compound droplet, which is suspended in another fluid in a parallel plate microchannel. The droplet is subjected to a transverse electric field in the presence of an imposed pressure driven flow. For the present study, a leaky dielectric model have been taken into consideration. When a concentric compound droplet migrates in a pressure driven flow, the inner droplet shifts from the concentric position and forms a eccentric configuration that finally leads to the rupture of the outer shell. The present investigation have uncovered that the temporal evolution of droplet eccentricity as well as the kinetics of the thinning of the outer droplet are markedly influenced by the strength of the electric field as well as the electric properties of the system. The present study also shows that the conversion of different modes of droplet pinch-off mode , such as the equatorial cap breaking-off or the hole-puncturing mode can be attained by altering the electric field strength and its electrical properties. Finally the present study depicts that these factors also alter the pinch-off time as well as its location on the outer interface. Therefore the outcomes of the present study offers an effective means of modulating the morphology of compound droplets in a confined channel by applying an electric field.