文档介绍：JOURNAL OF COLLOID AND INTERFACE SCIENCE 205, 26–41 (1998)
ARTICLE NO. CS985587
Broad Frequency Range Study of the Dielectric Properties
of Suspensions of Colloidal Polystyrene Particles
in Aqueous Electrolyte Solutions
Constantino Grosse,*,†,1 Monica Tirado,* Witold Pieper,‡ and Reinhard Pottel‡
*Instituto de Fisica, Universidad Nacional de Tucuman, Av. Independencia 1800, 4000 San Miguel de Tucuman, Argentina;
†Consejo Nacional de Investigaciones Cientificas y icas, Argentina; and ‡Drittes Physikalisches Institut,
Universitaet Goettingen, Burgerstrasse 42–44, D-37037 Goettingen, Germany
Received December 2, 1997; accepted April 14, 1998
At high frequencies, around 1–100 MHz, there is a much
The dielectric properties of suspensions of spherical polystyrene smaller relaxation with an amplitude of a few dielectric units
particles with radii of 34 and 50 nm, in aqueous electrolyte solu- (10–13).
tions were measured in the frequency range of 10 kHz to 30 GHz Most theoretical interpretations dealt with the low-frequency
using HP 4192A impedance and work analyzers, and
(also called counterion or ␣) relaxation (14–22). A unified
double path interferometers. The samples were prepared from the
stock suspensions with a high particle concentration (volume frac- treatment including both relaxations was only presented in (23)
tion of ), which were used either unchanged or diluted with (for the limiting case of low values of the zeta potential ) and
increasing amounts of water down to a concentration of . The in (24).
permittivity and total loss spectra showed three well-defined re- Comparison of experimental results with theoretical predic-
laxation regions, which could essfully be interpreted using an tions were made following two main routes: low-frequency
existing model [Grosse, C., J. Phys. Chem. 92, 3905 (1988)] (cor- dielectric spectra obtained on well-characterized suspensions at
rected by including a term of counteri