E. Lemaire et al., Mechanical stresses of a layer of colloidal particles aggregated by means of an electric field, J ELECTROST, 53(2), 2001, pp. 107-121
The stability of a colloidal system occupies a central position in colloid
science. According to the DLVO theory, the interparticle potential admits t
wo contributions: the Van der Waals attraction and the electrostatic repuls
ion. In this paper, we present a comparison of two methods to study the int
eraction forces between particles when their distance of separation varies.
The distance between particles is controlled through the application of a
DC electric field which is responsible for the formation of a concentrated
layer of particles. The cohesion inside the layer is determined either thro
ugh a mechanical method or through electrical measurements. In the first ca
se, a shear force is applied until, by viscous resuspension, the layer brea
ks apart. From the critical shear stress at which the layer destruction occ
urs, we deduce the cohesive force between the particles. The electrical mea
surement consists in inverting the polarity of the applied voltage after th
e layer has formed. The attractive forces between particles is then deduced
from the tensile voltage, the voltage at which the layer breaks. (C) 2001
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