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Scientific article
English

Forces between silica particles in the presence of multivalent cations

Published inJournal of Colloid and Interface Science, vol. 472, p. 108-115
Publication date2016
Abstract

Forces between negatively charged silica particles in aqueous electrolyte solutions were measured with the colloidal probe technique based on the atomic force microscope (AFM). The present study focuses on the comparison of monovalent and multivalent counterions, namely K+, Mg2+, and La3+. The force profiles can be well described with the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) down to distances of about 4 nm. At smaller distances, the forces become strongly repulsive due to additional non-DLVO repulsion. In the presence of La3+, one observes an additional attractive force with a range of about 1 nm at intermediate salt concentrations. This force is probably related to ion-ion correlations, but could also be influenced by surface charge heterogeneities or charge fluctuation forces.

Keywords
  • Atomic force microscope
  • Colloidal probe technique
  • Direct force measurement
  • Water-silica interface
  • Multivalent ion
Research group
Citation (ISO format)
VALMACCO, Valentina et al. Forces between silica particles in the presence of multivalent cations. In: Journal of Colloid and Interface Science, 2016, vol. 472, p. 108–115. doi: 10.1016/j.jcis.2016.03.043
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Article (Published version)
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Identifiers
ISSN of the journal0021-9797
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