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Charging and Aggregation of Positively Charged Colloidal Latex Particles in Presence of Multivalent Polycarboxylate Anions

Sadeghpour, Amin ; Szilágyi, István ; Borkovec, Michal

In: Zeitschrift für Physikalische Chemie, 2012, vol. 226, no. 7-8, p. 597-612

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    Title
    • Charging and Aggregation of Positively Charged Colloidal Latex Particles in Presence of Multivalent Polycarboxylate Anions
    Author
    • Sadeghpour, Amin. Karl-Franzens University, Physical Chemistry, Graz, Österreich
    • Szilágyi, István. University of Geneva, Department of Inorganic and Analytical Chemistry, Geneva, Schweiz
    • Borkovec, Michal. E-mail: michal.borkovec@unige.ch
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Zeitschrift für Physikalische Chemie, 2012, vol. 226, no. 7-8, p. 597-612. Oldenbourg Wissenschaftsverlag GmbH
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:292745
    Summary
    Colloidal stability and charging behavior of amidine latex particles in the presence of multivalent oligomers of acrylic acid was investigated by electrophoresis and light scattering. The data were interpreted quantitatively with the theory of Derjaguin, Landau, Verwey and Overbeek (DLVO) whereby the surface potentials were estimated from electrophoresis. Monomer leads to slow aggregation at low concentrations and to rapid aggregation at high concentrations, as characteristic for simple salts. The oligomers induce a charge reversal of the particles. Close to the isoelectric point (IEP) aggregation is rapid while the suspension becomes stable away from this point. At high oligomer concentrations, the aggregation becomes rapid again. The agreement between DLVO theory and experiment is good close to the IEP. At higher oligomer concentrations, the theory predicts larger stabilities than observed experimentally. While inter-particle forces seem to be well described by DLVO theory near the IEP, additional attractive non-DLVO forces are becoming relevant at higher concentrations