Stability and electrokinetic potential of silver iodide sol

Abstract

For a given rate of slow coagulation of a silver iodide sol by electrolytes, the ζ-potential of the particles has been measured both by the electrophoretic and electroosmotic methods. Both the methods yield the same value of true ζ-potential when correction for surface conductance of the colloidal particles is properly applied. The experimental results lead to the conclusion that in the presence of equicoagulating concentrations of electrolytes both χ, the specific surface conductance and ζ, the true electrokinetic potential remain constant. They thus confirm the view previously expressed by Ghosh that a given rate of coagulation of a colloid is characterised by a definite value of the true ζ-potential independent of the valency of the counter ions used.