Electric-field-induced displacement of a charged spherical colloid embedded in an elastic Brinkman medium - Condensed Matter > Soft Condensed MatterReportar como inadecuado




Electric-field-induced displacement of a charged spherical colloid embedded in an elastic Brinkman medium - Condensed Matter > Soft Condensed Matter - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: When an electric field is applied to an electrolyte-saturated polymer gelembedded with charged colloidal particles, the force that must be exerted bythe hydrogel on each particle reflects a delicate balance of electrical,hydrodynamic and elastic stresses. This paper examines the displacement of asingle charged spherical inclusion embedded in an uncharged hydrogel. Wepresent numerically exact solutions of coupled electrokinetic transport andelastic-deformation equations, where the gel is treated as an incompressible,elastic Brinkman medium. This model problem demonstrates how the displacementdepends on the particle size and charge, the electrolyte ionic strength, andYoung-s modulus of the polymer skeleton. The numerics are verified, in part,with an analytical boundary-layer theory valid when the Debye length is muchsmaller than the particle radius. Further, we identify a close connectionbetween the displacement when a colloid is immobilized in a gel and itsvelocity when dispersed in a Newtonian electrolyte. Finally, we describe anexperiment where nanometer-scale displacements might be accurately measuredusing back-focal-plane interferometry. The purpose of such an experiment is toprobe physicochemical and rheological characteristics of hydrogel composites,possibly during gelation.



Autor: Reghan J. Hill, Martin Ostoja-Starzewski

Fuente: https://arxiv.org/







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