Impurity effects at hydrophobic surfaces

Yuki Uematsu, Douwe Jan Bonthuis, Roland R. Netz*

*Korrespondierende/r Autor/in für diese Arbeit

Publikation: Beitrag in einer FachzeitschriftReview eines Fachbereichs (Review article)Begutachtung

Abstract

The effective charge of hydrophobic surfaces and in particular of the air–water interface is a crucial parameter for electrochemistry, colloidal chemistry and interfacial science, but different experiments give conflicting estimates. Zeta-potential and disjoining-pressure measurements point to a strongly negative surface charge, often interpreted as being due to adsorbing hydroxide ions. In contrast, surface tension measurements of acids and bases suggest the hydronium ion to be surface active, in agreement with some surface-specific non-linear spectroscopy results. The air–electrolyte interfacial tension exhibits a characteristic minimum at millimolar electrolyte concentration for all salts, the so-called Jones–Ray effect, which points to competitive adsorption mechanisms present in dilute electrolyte solutions. We show that all these puzzling experimental findings can be explained by the presence of trace amounts of surface-active charged impurities, most likely anionic surfactants.

Originalspracheenglisch
Seiten (von - bis)166-173
Seitenumfang8
FachzeitschriftCurrent Opinion in Electrochemistry
Jahrgang13
DOIs
PublikationsstatusVeröffentlicht - 1 Feb 2019
Extern publiziertJa

ASJC Scopus subject areas

  • Analytische Chemie
  • Elektrochemie

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