Electrohydrodynamics of Soft Particles: Role of the Interface

Dynamics of deformable particles in electric fields is a challenging problem because particle shape is not given a priori but is governed by the balance between interfacial, fluid and electric stresses. We develop theoretical analyses based on the Taylor's leaky dielectric model that quantitatively describe the behavior of surfactant-covered drops and vesicles in DC and AC fields, e.g. deformation and rotation. The role of Marangoni stresses and interface capacitance is investigated. Our theory explains why vesicles, unlike drops, may adopt prolate shapes at low frequencies, even if the interior fluid is less conducting than the suspending medium.