Dynamic Electrophoretic Mobility of Spherical Colloidal Particles in Salt-Free Concentrated Suspensions

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• 作者：F&eacute ; lix Carrique ; Emilio Ruiz-Reina ; Francisco J. Arroyo ; Marí ; a L. Jim&eacute ; nez ; Á ; ngel V. Delgado
• 刊名：Langmuir
• 出版年：2008
• 出版时间：March 18, 2008
• 年：2008
• 卷：24
• 期：6
• 页码：2395 - 2406
• 全文大小：304K
• 年卷期：v.24,no.6(March 18, 2008)
• ISSN：1520-5827

文摘

In this contribution, the dynamic electrophoretic mobility of spherical colloidal particles in a salt-free concentratedsuspension subjected to an oscillating electric field is studied theoretically using a cell model approach. Previouscalculations focusing the analysis on cases of very low or very high particle surface charge are analyzed and extendedto arbitrary conditions regarding particle surface charge, particle radius, volume fraction, counterion properties, andfrequency of the applied electric field (sub-GHz range). Because no limit is imposed on the volume fractions of solidsconsidered, the overlap of double layers of adjacent particles is accounted for. Our results display not only the so-calledcounterion condensation effect for high particle charge, previously described in the literature, but also its relativeinfluence on the dynamic electrophoretic mobility throughout the whole frequency spectrum. Furthermore, we observea competition between different relaxation processes related to the complex electric dipole moment induced on theparticles by the field, as well as the influence of particle inertia at the high-frequency range. In addition, the influencesof volume fraction, particle charge, particle radius, and ionic drag coefficient on the dynamic electrophoretic mobilityas a function of frequency are extensively analyzed.