Pairwise interactions of surfactant-covered drops in a uniform electric field

Chiara Sorgentone and Petia M. Vlahovska

Phys. Rev. Fluids 6, 053601 – Published 11 May 2021

Abstract

We study the effect of surfactant on the pairwise interactions of drops in an applied uniform dc electric field using a combination of numerical simulations based on a boundary integral formulation and an analytical theory assuming small drop deformations. The surfactant is assumed to be insoluble in the bulk-phase fluids. We show that the surfactant weakens the electrohydrodynamic flow, and thus dielectrophoretic interactions play a more prominent role in the dynamics of surfactant-covered drops compared to clean drops. If drop conductivity is the same as the suspending fluid, a nondiffusing surfactant can arrest the drops' relative motion thereby effectively preventing coalescence.

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Received 2 December 2020
Accepted 20 April 2021

DOI:https://doi.org/10.1103/PhysRevFluids.6.053601

Physics Subject Headings (PhySH)

Drop interactions Microfluidics

Fluid Dynamics

Authors & Affiliations

Chiara Sorgentone¹ and Petia M. Vlahovska ²

¹Department of Basic and Applied Sciences for Engineering, Sapienza Università di Roma, 00161 Rome, Italy
²Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois 60208, USA