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

TitleIons in an AC Electric Field: Strong Long-Range Repulsion between Oppositely Charged Surfaces.
Publication TypeJournal Article
Year of Publication2020
AuthorsRichter, Ł, Żuk, PJ, Szymczak, P, Paczesny, J, Bąk, KM, Szymborski, T, Garstecki, P, Stone, HA, Hołyst, R, Drummond, C
JournalPhys Rev Lett
Volume125
Issue5
Pagination056001
Date Published2020 Jul 31
ISSN1079-7114
Abstract

<p>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.</p>

DOI10.1103/PhysRevLett.125.056001
Alternate JournalPhys Rev Lett
PubMed ID32794889