# Charged colloids at the metal–electrolyte interface

1 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire
NIMBE UMR 3685 - Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M)
2 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes
SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay
Abstract : We discuss the peculiarities of the structure of the interface between a metal and a stable colloidal dispersion of charged nanoparticles in an electrolyte. It is demonstrated that a quasi-2D ionic structure of elevated density arises in its vicinity due to the effect of electrostatic image forces. The stabilized colloidal particles, being electroneutral and spatially distributed objects in the bulk of the electrolyte and approaching the interface, are attracted to it. In their turn, the counterions forming their coat partially retract into the 2D-layer, which results in an acquisition by the colloidal particle of the effective charge eZ*≫e and which, together with its mirror image, creates the electric dipole. The formed dipoles, possessing the moments directed perpendicularly to the interface, form the gas with repulsion between particles. The intensity of this repulsion, evidently, depends on the value of the effective charge eZ* acquired by the nanoparticle having lost a number of counterions. It can be related to the value of the excess osmotic pressure P$_{osm}$ measured in the experiment. On the other hand, this effective charge can be connected by means of the simple geometric consideration with the structural charge eZ of the nanoparticle core being in the bulk of the electrolyte.
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https://hal-cea.archives-ouvertes.fr/cea-03651864
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Submitted on : Tuesday, April 26, 2022 - 10:09:05 AM
Last modification on : Wednesday, April 27, 2022 - 3:40:01 AM
Long-term archiving on: : Wednesday, July 27, 2022 - 6:32:58 PM

### File

colloids-06-00025-v2.pdf
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### Citation

Ioulia Chikina, Sawako Nakamae, Valeriy Shikin, Andrey Varlamov. Charged colloids at the metal–electrolyte interface. Colloids and Interfaces, MDPI, 2022, 6, pp.25. ⟨10.3390/colloids6020025⟩. ⟨cea-03651864⟩

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