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Title

Interplay between Depletion and Double-Layer Forces Acting between Charged Particles in Solutions of Like-Charged Polyelectrolytes
Authors
Moazzami Gudarzi, Mohsen
Kremer, Tomislav
Valmacco, Valentina
Maroni, Plinio
Borkovec, Michal
Trefalt, Gregor
Published in Physical Review Letters. 2016, vol. 117, no. 8
Abstract Direct force measurements between negatively charged silica particles in the presence of a like-charged strong polyelectrolyte were carried out with an atomic force microscope. The force profiles can be quantitatively interpreted as a superposition of depletion and double-layer forces. The depletion forces are modeled with a damped oscillatory profile, while the double-layer forces with the mean-field Poisson- Boltzmann theory for a strongly asymmetric electrolyte, whereby an effective valence must be assigned to the polyelectrolyte. This effective valence is substantially smaller than the bare valence due to ion condensation effects. The unusual aspect of the electrical double layer in these systems is the exclusion of the like-charged polyelectrolyte from the vicinity of the surface, leading to a strongly nonexponential diffuse ionic layer that is dominated by counterions and has a well-defined thickness. As the oscillatory depletion force sets in right after this layer, this condition can be used to predict the phase of the oscillatory depletion force.
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Article (Published version) (562 Kb) - public document Free access
Structures
Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée
Research group Groupe Borkovec
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(ISO format) 		MOAZZAMI GUDARZI, Mohsen et al. Interplay between Depletion and Double-Layer Forces Acting between Charged Particles in Solutions of Like-Charged Polyelectrolytes. In: Physical Review Letters, 2016, vol. 117, n° 8. https://archive-ouverte.unige.ch/unige:103253

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Deposited on : 2018-03-28

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