Conductivity of a concentrated colloidal suspension of spherical particles in an alternating electric field
Identificadores
URI: http://hdl.handle.net/10481/28444Metadata
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Arroyo Roldán, Francisco J.; Carrique Fernández, Félix; Jiménez Olivares, María Luisa; Delgado Mora, Ángel VicenteEditorial
Uniwersytetu Marii Curie-Skłodowskiej
Materia
Chemistry Química Spherical particles Electric field Conductivity
Date
2005Referencia bibliográfica
Arroyo, F.J.; et al. Conductivity of a concentrated colloidal suspension of spherical particles in an alternating electric field. Annales Universitatis Mariae Curie-Skłodowska. Sectio AA, Chemia, 60(1): 1-22 (2005). [http://hdl.handle.net/10481/28444]
Sponsorship
Financial support for this work by MCyT, Spain (Project MAT 2004-00866), and FEDER funds is gratefully acknowledged.Abstract
In this paper the complex (ac) conductivity of a concentrated suspension of
spherical colloidal particles is considered in the light of a cell model. Previous
works have dealt with the study of the conductivity of a concentrated colloidal
suspension for general conditions, including arbitrary zeta potential, particle
volume fraction, double-layer thickness, and ionic properties of the solution,
but only the static case (dc electric fields) was addressed. In this contribution,
the complex conductivity of a concentrated suspension is studied for the same
general conditions as in the static case. The numerical data presented in this
paper cover a wide range of typical situations including the special case of
overlap of double layers of adjacent particles. Like in the static case, the
treatment is based on the use of a cell model to account for hydrodynamic and
electrical interactions between particles. The two relaxation processes
occurring in the frequency range of interest (alpha and Maxwell-Wagner-
O’Konski) are analyzed for different values of the ionic strength, particle
radius, zeta potential and particle concentration. Roughly speaking, these two
relaxations tend to overlap in frequency as the volume fraction of solids
increases for otherwise general conditions; in such cases, no clear distinction
can be established between them. On the other hand, considerable attention has
also been devoted to the numerical analysis of the complex conductivity for
those special situations where overlapping between double layers is nonnegligible.
Finally, a comparison between theoretical predictions and some
experimental results is shown, revealing a general good agreement.