Concentration profiles of a colloidal mixture near a charged wall

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Abstract
The structure of a model two-component colloidal mixture in the vicinity of a charged wall is studied in the framework of the Derjaguin–Landau–Verweg–Overbeek potential and the hypernetted-chain approximation for the particle–particle and wall–particle direct correlation functions as the closure for the bulk and wall–particle Ornstein–Zernike equations. It is found that for strongly repulsive walls the structure of the inhomogeneous mixture near the wall only depends on the bulk parameters. For neutral and attractive walls, a monolayer of colloidal particles adjacent to the wall is formed. Depending on the charge asymmetry between the two colloidal species, the composition of this monolayer indicates a preferential electrostatic adsorption of the more highly charged species. For large charge asymmetry between the two species, a distinct segregation effect is predicted.