Scientific article
English

Attractive Forces between Charged Colloidal Particles Induced by Multivalent Ions Revealed by Confronting Aggregation and Direct Force Measurements

Published inJournal of Physical Chemistry Letters, vol. 4, no. 4, p. 648-652
Publication date2013
Abstract

Interactions involving charged particles in the presence of multivalent ions are relevant in wide-range of phenomena, including condensation of nucleic acids, cement hardening, or water treatment. Here, we study such interactions by combining direct force measurements with atomic force microscopy (AFM) and aggregation studies with time-resolved light scattering for particles originating from the same colloidal suspension for the first time. Classical DLVO theory is found to be only applicable for monovalent and divalent ions. For ions of higher valence, charge inversion and additional non-DLVO attractive forces are observed. These attractive forces can be attributed to surface charge heterogeneities, which leads to stability ratios that are calculated from direct force measurements to be higher than the experimental ones. Ion–ion correlations are equally important as they induce the charge inversion in the presence of trivalent or tetravalent ions, and they enhance the surface charge heterogeneities. Such heterogeneities therefore play an essential role in controlling interactions in particle suspensions containing multivalent ions.

Keywords
  • Surface forces
  • Atomic force microscopy
  • Colloidal probe technique
  • Particle stability
  • Light scattering
  • Multivalent ions
Citation (ISO format)
SINHA, Prashant et al. Attractive Forces between Charged Colloidal Particles Induced by Multivalent Ions Revealed by Confronting Aggregation and Direct Force Measurements. In: Journal of Physical Chemistry Letters, 2013, vol. 4, n° 4, p. 648–652. doi: 10.1021/jz4000609
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Additional URL for this publicationhttps://pubs.acs.org/doi/10.1021/jz4000609
Journal ISSN1948-7185
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