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Volume 78, Number 3, May 2007
Article Number 38002
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 17 April 2007
EPL, 78 (2007) 38002
DOI: 10.1209/0295-5075/78/38002

Interaction between charged colloids in a low dielectric constant solvent

E. Allahyarov1, 2, E. Zaccarelli3, F. Sciortino3, P. Tartaglia4 and H. Löwen1

1  Institut für Theoretische Physik, Heinrich-Heine-Universität Düsseldorf - D-40225 Düsseldorf, Germany
2  Institute for High Temperatures, Russian Academy of Sciences - Izhorskaya 13/19, 117419 Moscow, Russia
3  Dipartimento di Fisica and CNR-INFM-SOFT, Università di Roma La Sapienza - P.le A. Moro 2, I-00185 Roma, Italy
4  Dipartimento di Fisica and CNR-INFM-SMC, Università di Roma La Sapienza - P.le A. Moro 2, I-00185 Roma, Italy

received 9 December 2006; accepted in final form 21 March 2007; published May 2007
published online 17 April 2007

Based on computer simulations of the primitive model of electrolytes, we show that the effective interaction between low-charge colloids in solvents of low or moderate dielectric constant depends crucially on the salt concentration. While in the absence of salt the interaction is repulsive in agreement with Derjaguin-Landau-Verwey-Overbeek theory, depletion of salt Bjerrum pairs around the colloids leads to an attraction between like-charge colloids even at small salt concentrations.

82.70.Dd - Colloids.
61.20.Qg - Structure of associated liquids: electrolytes, molten salts, etc..
87.15.Aa - Theory and modeling; computer simulation.

© Europhysics Letters Association 2007