Ions in an AC Electric Field: Strong Long-Range Repulsion between Oppositely Charged Surfaces

Łukasz Richter, Paweł J. Żuk, Piotr Szymczak, Jan Paczesny, Krzysztof M. Bąk, Tomasz Szymborski, Piotr Garstecki, Howard A. Stone, Robert Hołyst, Carlos Drummond

Research output: Contribution to journalArticle

Abstract

Two oppositely charged surfaces separated by a dielectric medium attract each other. In contrast we observe a strong repulsion between two plates of a capacitor that is filled with an aqueous electrolyte upon application of an alternating potential difference between the plates. This long-range force increases with the ratio of diffusion coefficients of the ions in the medium and reaches a steady state after a few minutes, which is much larger than the millisecond timescale of diffusion across the narrow gap. The repulsive force, an order of magnitude stronger than the electrostatic attraction observed in the same setup in air, results from the increase in osmotic pressure as a consequence of the field-induced excess of cations and anions due to lateral transport from adjacent reservoirs.

Original languageEnglish (US)
Pages (from-to)56001
Number of pages1
JournalPhysical review letters
Volume125
Issue number5
DOIs
StatePublished - Jul 31 2020

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Richter, Ł., Żuk, P. J., Szymczak, P., Paczesny, J., Bąk, K. M., Szymborski, T., Garstecki, P., Stone, H. A., Hołyst, R., & Drummond, C. (2020). Ions in an AC Electric Field: Strong Long-Range Repulsion between Oppositely Charged Surfaces. Physical review letters, 125(5), 56001. https://doi.org/10.1103/PhysRevLett.125.056001