Interplay between Depletion and Double-Layer Forces Acting between Charged Particles in Solutions of Like-Charged Polyelectrolytes

Article Article scientifique Article Interplay between Depletion and Double-Layer Forces Acting between Charged Particles in Solutions of Like-Charged Polyelectrolytes eng 2016 author Moazzami Gudarzi Mohsen 788987 author Kremer Tomislav 833259 author Valmacco Valentina 765249 author Maroni Plinio 644101 author Borkovec Michal 134121 author Trefalt Gregor 786132 10.1103/PhysRevLett.117.088001 0031-9007 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. Dewey 540 40 Département de chimie minérale, analytique et appliquée 145 false 773 Groupe Borkovec Physical Review Letters 117 8 b676fd10-5ab3-4baf-81d6-7e72444c9168 Article (Published version) Public PhysRevLett.117.088001.pdf 575565 application/pdf openAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

Title	Published in	Access level	OA Policy	Year	Views	Downloads

Interplay between Depletion and Double-Layer Forces Acting between Charged Particles in Solutions of Like-Charged Polyelectrolytes	Physical Review Letters			2016	448	205

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