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Charged Semi‐Permeable Shell with Encapsulated Polyions: Concentration Profile, Surface Potential, and Electrostatic Pressure
Author(s) -
Tsekov Roumen,
Vinogradova Olga I.
Publication year - 2007
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200750615
Subject(s) - charge density , shell (structure) , osmotic pressure , electrostatics , surface charge , donnan potential , diffusion , polyelectrolyte , chemical physics , materials science , counterion , suspension (topology) , colloid , electrophoresis , charge (physics) , ion , thermodynamics , chemistry , physics , composite material , electrolyte , polymer , chromatography , biochemistry , mathematics , organic chemistry , electrode , quantum mechanics , homotopy , pure mathematics
Summary: We study theoretically the electrostatic equilibrium for a charged shell filled with a suspension of polyions (e.g., colloids, polyelectrolytes, etc.) and immersed in an infinite salt‐free reservoir. The shell is impermeable for polyions, but allows free diffusion of counterions. From the solution of the linearized Poisson‐Boltzmann equation we obtain the distribution of the potential and concentration profiles for polyions. We then derive explicit formulas for the electrostatic pressure exerted by the shell. If the overall charge of the filled shell has the same sign as the surface alone the pressure on the shell increases with increase of the surface charge density. Otherwise the surface charge density suppresses the electro‐osmotic pressure due to the electrostatic attraction between the oppositely charged polyions and shell.