TU Darmstadt / ULB / TUprints

Impact of surface charges on the solvation forces in confined colloidal solutions

Grandner, Stefan ; Zeng, Yan ; Klitzing, Regine von ; Klapp, Sabine H. L. (2022)
Impact of surface charges on the solvation forces in confined colloidal solutions.
In: The Journal of Chemical Physics, 131 (15)
doi: 10.26083/tuprints-00022935
Article, Secondary publication, Publisher's Version

[img] Text
Copyright Information: In Copyright.

Download (826kB)
Item Type: Article
Type of entry: Secondary publication
Title: Impact of surface charges on the solvation forces in confined colloidal solutions
Language: English
Date: 2022
Place of Publication: Darmstadt
Publisher: AIP Publishing
Journal or Publication Title: The Journal of Chemical Physics
Volume of the journal: 131
Issue Number: 15
Collation: 11 Seiten
DOI: 10.26083/tuprints-00022935
Corresponding Links:
Origin: Secondary publication service

Combining computer simulations and experiments we address the impact of charged surfaces on the solvation forces of a confined, charged colloidal suspension (slit-pore geometry). Investigations based on the colloidal-probe atomic-force-microscope technique indicate that an increase in surface charges markedly enhances the oscillations of the force in terms of their amplitude. To understand this effect on a theoretical level we perform grand-canonical Monte-Carlo simulations (GCMC) of a coarse-grained model system. It turns out that various established approaches of the interaction between a charged colloid and a charged wall, such as linearized Poisson–Boltzmann (PB) theory involving the bulk screening length, do not reproduce the experimental observations. We thus introduce a modified PB potential with a space-dependent screening parameter. The latter takes into account, in an approximate way, the fact that the charged walls release additional (wall) counterions which accumulate in a thin layer at the surface(s). The resulting, still purely repulsive fluid-wall potential displays a nonmonotonic behavior as function of the surface potential with respect to the strength and range of repulsion. GCMC simulations based on this potential reproduce the experimentally observed charge-induced enhancement in the force oscillations. We also show, both by experiment and by simulations, that the asymptotic wave- and decay length of the oscillating force do not change with the wall charge, in agreement with predictions from density functional theory.

Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-229350
Classification DDC: 500 Science and mathematics > 530 Physics
Divisions: 05 Department of Physics > Institute for Condensed Matter Physics
Date Deposited: 28 Nov 2022 13:52
Last Modified: 15 May 2023 11:37
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/22935
PPN: 507645154
Actions (login required)
View Item View Item