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Electrohydrodynamics modeling of droplet actuation on a solid surface by surfactant-mediated electrodewetting

Weiqi Chu1, Hangjie Ji2, Qining Wang3, Chang-Jin “CJ” Kim3, and Andrea L. Bertozzi1,3

  • 1Department of Mathematics, University of California Los Angeles, Los Angeles, California 90095, USA
  • 2Department of Mathematics, North Carolina State University, Raleigh, North Carolina 27695, USA
  • 3Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA

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Phys. Rev. Fluids 8, 073701 – Published 21 July, 2023

DOI: https://doi.org/10.1103/PhysRevFluids.8.073701

Abstract

We propose an electrohydrodynamics model to describe the dynamic evolution of a slender drop containing a dilute ionic surfactant on a naturally wettable surface, with a varying external electric field. This unified model reproduces fundamental microfluidic operations controlled by electrical signals, including dewetting, rewetting, and droplet shifting. In this paper, lubrication theory analysis and numerical simulations illustrate how to electrically control the wettability of surface via the charged surfactant. Our numerical results show that electric field promotes dewetting by attracting ionic surfactants onto the transition thin-film region and promotes rewetting by attracting them away from the region.

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Phys. Rev. Fluids 8, 073701– Published 21 July, 2023
  • Received 20 November 2022
  • Accepted 15 June 2023
Article part of CHORUS
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