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Ions Adsorbed at Amorphous Solid/Solution Interfaces Form Wigner Crystal-like Structures.

Wang, Jianan; Li, Hua; Tavakol, Mahdi; Serva, Alessandra; Nener, Brett; Parish, Giacinta; Salanne, Mathieu; Warr, Gregory G; Voïtchovsky, Kislon; Atkin, Rob

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Authors

Jianan Wang

Hua Li

Alessandra Serva

Brett Nener

Giacinta Parish

Mathieu Salanne

Gregory G Warr

Rob Atkin



Abstract

When a surface is immersed in a solution, it usually acquires a charge, which attracts counterions and repels co-ions to form an electrical double layer. The ions directly adsorbed to the surface are referred to as the Stern layer. The structure of the Stern layer normal to the interface was described decades ago, but the lateral organization within the Stern layer has received scant attention. This is because instrumental limitations have prevented visualization of the ion arrangements except for atypical, model, crystalline surfaces. Here, we use high-resolution amplitude modulated atomic force microscopy (AFM) to visualize the lateral structure of Stern layer ions adsorbed to polycrystalline gold, and amorphous silica and gallium nitride (GaN). For all three substrates, when the density of ions in the layer exceeds a system-dependent threshold, correlation effects induce the formation of close packed structures akin to Wigner crystals. Depending on the surface and the ions, the Wigner crystal-like structure can be hexagonally close packed, cubic, or worm-like. The influence of the electrolyte concentration, species, and valence, as well as the surface type and charge, on the Stern layer structures is described. When the system parameters are changed to reduce the Stern layer ion surface excess below the threshold value, Wigner crystal-like structures do not form and the Stern layer is unstructured. For gold surfaces, molecular dynamics (MD) simulations reveal that when sufficient potential is applied to the surface, ion clusters form with dimensions similar to the Wigner crystal-like structures in the AFM images. The lateral Stern layer structures presented, and in particular the Wigner crystal-like structures, will influence diverse applications in chemistry, energy storage, environmental science, nanotechnology, biology, and medicine.

Citation

Wang, J., Li, H., Tavakol, M., Serva, A., Nener, B., Parish, G., …Atkin, R. (2024). Ions Adsorbed at Amorphous Solid/Solution Interfaces Form Wigner Crystal-like Structures. ACS Nano, 18(1), 1181-1194. https://doi.org/10.1021/acsnano.3c11349

Journal Article Type Article
Acceptance Date Dec 14, 2023
Online Publication Date Dec 20, 2023
Publication Date Jan 9, 2024
Deposit Date Mar 20, 2024
Publicly Available Date Mar 20, 2024
Journal ACS nano
Print ISSN 1936-0851
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 18
Issue 1
Pages 1181-1194
DOI https://doi.org/10.1021/acsnano.3c11349
Keywords solid/liquid interface, AFM, electrolyte, electrical double layer, Stern layer
Public URL https://durham-repository.worktribe.com/output/2085033

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