Charged Surface-Active Impurities at Nanomolar Concentration Induce Jones-Ray Effect

Yuki Uematsu, Douwe Jan Bonthuis, Roland R. Netz

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The electrolyte surface tension exhibits a characteristic minimum around a salt concentration of 1 mM for all ion types, known as the Jones-Ray effect. We show that a consistent description of the experimental surface tension of salts, bases, and acids is possible by assuming charged impurities in the water with a surface affinity typical for surfactants. Comparison with experimental data yields an impurity concentration in the nanomolar range, well below the typical experimental detection limit. Our modeling reveals salt-screening enhanced impurity adsorption as the mechanism behind the Jones-Ray effect: for very low salt concentration added salt screens the electrostatic repulsion between impurities at the surface, which dramatically increases impurity adsorption and thereby reduces the surface tension.

Original languageEnglish
Pages (from-to)189-193
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume9
Issue number1
DOIs
Publication statusPublished - 4 Jan 2018
Externally publishedYes

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ASJC Scopus subject areas

  • Materials Science(all)

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