Wetting Effect Induced Depletion and Adsorption Layers: Diffuse Interface Perspective

Abstract: When a multi‐component fluid contacts arigid solid substrate, the van der Waals interaction between fluids and substrate induces a depletion/adsorption layer depending on the intrinsic wettability of the system. In this study, we investigate the depletion/adsorption behaviors of A−B fluid system. We derive analytical expressions for the equilibrium layer thickness and the equilibrium composition distribution near the solid wall, based on the theories of de Gennes and Cahn. Our derivation is verified through phase‐field simulations, wherein the substrate wettability, A−B interfacial tension, and temperature are systematically varied. Our findings underscore two pivotal mechanisms governing the equilibrium layer thickness. With an increase in the wall free energy, the substrate wettability dominates the layer formation, aligning with de Gennes’ theory. When the interfacial tension increases, or temperature rises, the layer formation is determined by the A−B interactions, obeying Cahn's theory. Additionally, we extend our study to non‐equilibrium systems where the initial composition deviates from the binodal line. Notably, macroscopic depletion/adsorption layers form on the substrate, which are significantly thicker than the equilibrium microscopic layers. This macroscopic layer formation is attributed to the interplay of phase separation and Ostwald ripening. We anticipate that the present finding could deepen our knowledge on the depletion/adsorption behaviors of immiscible fluids.

Standort
Deutsche Nationalbibliothek Frankfurt am Main
Umfang
Online-Ressource
Sprache
Englisch

Erschienen in
Wetting Effect Induced Depletion and Adsorption Layers: Diffuse Interface Perspective ; day:12 ; month:06 ; year:2024 ; extent:12
ChemPhysChem ; (12.06.2024) (gesamt 12)

Urheber
Zhang, Haodong
Zhang, Hongmin
Wang, Fei
Nestler, Britta

DOI
10.1002/cphc.202400086
URN
urn:nbn:de:101:1-2406131404591.601555288101
Rechteinformation
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Letzte Aktualisierung
14.08.2025, 10:56 MESZ

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Beteiligte

  • Zhang, Haodong
  • Zhang, Hongmin
  • Wang, Fei
  • Nestler, Britta

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