Ion−Ion Correlation and Charge Reversal at Titrating Solid Interfaces

• Published in: Langmuir Vol. 25; no. 13; pp. 7209 - 7213
• Main Authors: Labbez, Christophe, Jönsson, Bo, Skarba, Michal, Borkovec, Michal
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.07.2009
• Subjects: Chemical Physics; Chemical Sciences; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Kemi; Natural Sciences; Naturvetenskap; Physics; Surface physical chemistry; Teoretisk kemi; Theoretical Chemistry; Monte Carlo method; Binary compound; Surface charge; Correlation; Simulation; Counter ion; Ions; Silica; Interface; Solid
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la900853e

Confronting grand canonical titration Monte Carlo simulations (MC) with recently published titration and charge reversal (CR) experiments on silica surfaces by Dove and Craven (Dove, P. M.; Craven, C. M. Geochim. Cosmochim. Acta 2005, 69, 4963−4970) and van der Heyden et al. (van der Heyden, F. H. J.; Stein, D.; Besteman, K.; Lemay, S. G.; Dekker, C. Phys. Rev. Lett. 2006, 96, 224502), we show that ion−ion correlations quantitatively explain why divalent counterions strongly promote surface charge which, in turn, eventually causes a CR. Titration and CR results from simulations and experiments are in excellent agreement without any fitting parameters. This is the first unambiguous evidence that ion−ion correlations are instrumental in the creation of highly charged surfaces and responsible for their CR. Finally, we show that charge correlations result in “anomalous” charge regulation in strongly coupled conditions in qualitative disagreement with its classical treatment.