Journal Article

IMPULSE-2023-00126

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png When Ions Defy Electrostatics: The Case of Superchaotropic Nanoion Adsorption

Hohenschutz, M. ; Dufrêche, J.-F. ; Diat, O. ; Bauduin, P. (Corresponding author)

2023
ACS Washington, DC

Please use a persistent id in citations: doi:10.1021/acs.jpclett.3c00095

Abstract: Nanometer-sized anions, like polyoxometalates and borate clusters, bind to nonionic hydrated matter driven by the chaotropic effect, which arises from the favorable dehydration of the ions. Herein, we evaluate the adsorption and activity coefficient of the superchaotropic Keggin polyoxometalate SiW12O404– (SiW) on nonionic surfactant (C8E4) micelles by modeling small-angle X-ray and neutron-scattering spectra. Neither hard sphere nor electrostatic repulsion models reproduce the experimental activity coefficient of adsorbed SiW ions on the micelles. However, the activity and binding of SiW on the micelles is well-described by a Langmuir adsorption isotherm. These results imply that adsorbed SiW ions are non-interacting and “create” around themselves adsorption sites on the micelle. The temperature dependence of the adsorption constant showed that the SiW adsorption is enthalpically driven and entropically unfavorable, in line with the typical chaotropic thermochemical signature. The adsorption enthalpy can be split into an electrostatic term and a water-recovery term to evaluate and qualitatively predict the superchaotropicity of a nanoion.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Soft Condensed Matter (2nd)

Note: I don't have access to this article but the supporting information mentions measurements at SANS-1 and I did have this user group as local contact. So very strong suspicion that SANS-1 data are included.

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Contributing Institute(s):

1. SANS1 (SANS1)
2. Users (Users)

Experiment(s):

1. SANS-1: Small angle neutron scattering (NL4a)

Appears in the scientific report 2023

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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