Ionic association and Wien effect in 2D confined electrolytes
Toquer D, Bocquet L, Robin P. 2025. Ionic association and Wien effect in 2D confined electrolytes. Journal of Chemical Physics. 162(6), 064703.
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Author
Toquer, Damien;
Bocquet, Lydéric;
Robin, PaulISTA 

Corresponding author has ISTA affiliation
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Abstract
Recent experimental advances in nanofluidics have allowed to explore ion transport across molecular-scale pores, in particular, for iontronic applications. Two-dimensional nanochannels—in which a single molecular layer of electrolyte is confined between solid walls—constitute a unique platform to investigate fluid and ion transport in extreme confinement, highlighting unconventional transport properties. In this work, we study ionic association in 2D nanochannels, and its consequences on non-linear ionic transport, using both molecular dynamics simulations and analytical theory. We show that under sufficient confinement, ions assemble into pairs or larger clusters in a process analogous to a Kosterlitz–Thouless transition, here modified by the dielectric confinement. We further show that the breaking of pairs results in an electric-field dependent conduction, a mechanism usually known as the second Wien effect. However the 2D nature of the system results in non-universal, temperature-dependent, scaling of the conductivity with electric field, leading to ionic coulomb blockade in some regimes. A 2D generalization of the Onsager theory fully accounts for the non-linear transport. These results suggest ways to exploit electrostatic interactions between ions to build new nanofluidic devices.
Publishing Year
Date Published
2025-02-14
Journal Title
Journal of Chemical Physics
Publisher
AIP Publishing
Acknowledgement
The authors thank B. Coquinot and G. Monet for fruitful discussions. L.B. acknowledges support from ERC-Synergy Grant Agreement No. 101071937, n-AQUA. P.R. acknowledges support from the European Union’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie Grant Agreement No. 101034413.
Volume
162
Issue
6
Article Number
064703
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eISSN
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Cite this
Toquer D, Bocquet L, Robin P. Ionic association and Wien effect in 2D confined electrolytes. Journal of Chemical Physics. 2025;162(6). doi:10.1063/5.0241949
Toquer, D., Bocquet, L., & Robin, P. (2025). Ionic association and Wien effect in 2D confined electrolytes. Journal of Chemical Physics. AIP Publishing. https://doi.org/10.1063/5.0241949
Toquer, Damien, Lydéric Bocquet, and Paul Robin. “Ionic Association and Wien Effect in 2D Confined Electrolytes.” Journal of Chemical Physics. AIP Publishing, 2025. https://doi.org/10.1063/5.0241949.
D. Toquer, L. Bocquet, and P. Robin, “Ionic association and Wien effect in 2D confined electrolytes,” Journal of Chemical Physics, vol. 162, no. 6. AIP Publishing, 2025.
Toquer D, Bocquet L, Robin P. 2025. Ionic association and Wien effect in 2D confined electrolytes. Journal of Chemical Physics. 162(6), 064703.
Toquer, Damien, et al. “Ionic Association and Wien Effect in 2D Confined Electrolytes.” Journal of Chemical Physics, vol. 162, no. 6, 064703, AIP Publishing, 2025, doi:10.1063/5.0241949.
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PMID: 39932241
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arXiv 2410.03316