Multimodal breakup of a double emulsion droplet under an electric field

Abstract

We study the multimodal breakup of a double emulsion droplet under a uniform direct current electric field.

Compound‐Droplet‐Pairs‐Filled Hydrogel Microfiber for Electric‐Field‐Induced Selective Release

“…A square‐wave AC voltage signal is applied through the acupuncture needles to develop AC electric field between the electrode pair. When the double‐emulsion droplets wrapped by microfibers are manually placed between electrodes and exposed to an AC electric field (100 kHz, 32.5 V), the inner core travels to one side of the shell interface due to the asymmetric Maxwell stress, which acts on the field‐induced dipole moment within the compound droplet having an initial core eccentricity . Meanwhile, since the time‐averaged dielectrophoresis (DEP) surface stress tends to mechanically expand the inner core and compress the outer surface of oil membrane at the same time, the oil film thins out gradually and eventually ruptures, ejecting the core liquid into the surrounding microfiber cavity.…”

Electro-Hydrodynamics of Emulsion Droplets: Physical Insights to Applications

“…On the other hand, if shell liquid has large electric conductivity and , it behaves like a shield and electric potential lines cannot penetrate through it, resulting in a negligible core deformation (See Figure 8 C). While Behjatian and Esmaeeli reported a steady droplet configuration under a weak electric field, it was later reported in an experimental study [ 13 ] that owing to electrophoretic effects and the presence of net charge arising from the existence of electric double/diffuse charge layers on the droplet, the steady configuration was not possible for some of the cases. As the charged core droplet experiences the electric field, it moves towards the droplet side apex and is eventually dispensed into the ambient.…”

“…This feature of multi-phase droplets is relatively less explored. Only a few studies have explored the breakups within a certain range of electric and hydrodynamic properties [ 13 , 14 , 16 , 25 , 30 , 95 , 152 ]. In one of the earliest studies, Ha and Yang established the breakups of conducting emulsion droplets comprised of inhomogeneous inner phase encapsulated by an outer membrane phase suspended in silicone oil [ 25 ].…”

“…This was due to less penetration of electric potential as the shell was acting as a shield. Recently, Abbasi et al explored the dynamics of a double-emulsion droplet with a low electrical conductivity shell beyond the small deformation limit in two separate studies and explored various breakup modes of a core droplet under varying physical and electrical parameters, such as radius ratio, electric capillary number, and/or interfacial tension [ 13 , 16 ]. In the former, breakups of a A/B/A type of double-emulsion comprised of castor oil/silicone oil/castor oil (core/shell/ambient) for which PO mode of deformation occurs is thoroughly explored.…”

“…Subsequently, the validation of the model was reported, and more accurate models emerged [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Recent EHD studies have explored more complex EHD interface topologies related to multiple phase emulsion droplets, and also covered the broader aspects, such as the emulsion instabilities, breakups, and particles manipulation at the emulsion interface forming novel colloidal assemblies [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Though it has been almost six decades since the research in this area commenced, it is only until recently that a few studies pertaining to the droplet EHD with applicative prospects have been reported [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ,…”