Cationic Hofmeister Series of Wettability Alteration in Mica-Water-Alkane Systems

B. Bera, N. Kumar, M. H.G. Duits, M. A. Cohen Stuart, F. Mugele* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)
79 Downloads (Pure)

Abstract

The specific interaction of ions with macromolecules and solid-liquid interfaces is of crucial importance to many processes in biochemistry, colloid science, and engineering, as first pointed out by Hofmeister in the context of (de)stabilization of protein solutions. Here, we use contact angle goniometry to demonstrate that the macroscopic contact angle of aqueous chloride salt solutions on mica immersed in ambient alkane increases from near-zero to values exceeding 10°, depending on the type and concentration of cations and pH. Our observations result in a series of increasing ability of cations to induce partial wetting in the order Na+, K+ < Li+ < Rb+ < Cs+ < Ca2+ < Mg2+ < Ba2+. Complementary atomic force microscopy measurements show that the transition to partial wetting is accompanied by cation adsorption to the mica-electrolyte interface, which leads to charge reversal in the case of divalent cations. In addition to electrostatics, hydration forces seem to play an important role, in particular for the monovalent cations.

Original languageEnglish
Pages (from-to)13574-13583
Number of pages10
JournalLangmuir
Volume34
Issue number45
DOIs
Publication statusPublished - 13 Nov 2018

Keywords

  • UT-Hybrid-D

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