Page 216 - Introduction to Colloid and Surface Chemistry

Charged interfaces 205
3. Permittivity and viscosity are constant throughout the mobile part
of the double layer, which is described by the classical Gouy-
Chapman theory.
4. Only one type each of positive and negative ions are present in the
mobile part of the double layer.

Figures 7.12 and 7.13 show the result of a selection of these
computations.

Figure 7.12 Eiectrophoretic mobility and zeta potential for spherical colloidal
2
particles in 1-1 electrolyte solutions (A+ = A_ = 70 H~' cm mol"'). The curves refer
to eflkT = 1, 2, 3 and 4 (i.e. £/mV = 25.6, 51.2, 76.8 and 102.4 at 25°C) [After
P.M. Wiersema, A.L. Loeb and J.Th.G. Overbeek, /. Colloid Interface ScL, 22, 78
(1966)]

Investigations of the electrophoretic behaviour of monodispersed
carboxylated polystyrene latex dispersions as a function of particle
191
size and electrolyte concentration by Shaw and Ottewill have
confirmed, at least qualitatively, the existence of KO and relaxation
effects.