Ion size effects on the electrokinetics of salt-free concentrated suspensions in ac fields

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:387

Article

Roa, Rafael¹  Carrique, Felix¹  Ruiz-Reina, Emilio¹ 

[1] Univ Malaga, E-29071 Malaga, Spain

关键词: Ion size effects;    Electrokinetics;    Salt-free;    Concentrated suspensions;    Dynamic mobility;    Dielectric response;   

DOI  :  10.1016/j.jcis.2012.07.094

来源: Elsevier

【 摘 要 】

We analyze the influence of finite ion size effects in the response of a salt-free concentrated suspension of spherical particles to an oscillating electric field. Salt-free suspensions are just composed of charged colloidal particles and the added counterions released by the particles to the solution that counterbalance their surface charge. In the frequency domain, we study the dynamic electrophoretic mobility of the particles and the dielectric response of the suspension. We find that the Maxwell-Wagner-O'Konski process associated with the counterions condensation layer is enhanced for moderate to high particle charges, yielding an increment of the mobility for such frequencies. We also find that the increment of the mobility grows with ion size and particle charge. All these facts show the importance of including ion size effects in any extension attempting to improve standard electrokinetic models. (C) 2012 Elsevier Inc. All rights reserved.

【 授权许可】

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