Double emulsion droplet breakup under DC electric field

We studied experimentally, theoretically, and numerically how electrohydrodynamic deformation and breakup of double emulsion droplets occurs under DC electric field. Experiments show that there are four distinct modes of breakup depending on the viscosity ratio, electrical conductivity ratio, permittivity ratio, and volume ratio of the core to shell liquid. The breakup modes are classified such as a unidirectional breakup mode, two different bidirectional breakup modes, and a tip-streaming breakup mode. In order to investigate the dynamics of core droplet migration and the thin film drainage of shell liquid, theoretical studies are performed aided by numerical simulation. For droplet breakup, sufficiently large Maxwell stresses (∼εE²) are essential in comparison with the capillary pressure (∼γ/r_c) of the core. During breakup, the Plateau’s criteria and geometry effect are critical factor determining the breakup modes. We believe that this study could provide impacts for the comprehension of double emulsion droplet functionalities in various applications including drug delivery, material science, biological and chemical engineering.