Stability of silicon and titanium carbide suspensions in poly(ethylene oxide) solutions 1. Poly(ethylene oxide) adsorption and its effect on the electrosurface properties of SiC and TiC suspensions

Abstract

The nature of the surface charge and the effect of indifferent electrolytes (nitrates of alkali and alkaline earth metals) and non-indifferent electrolytes (HCl and KOH) on the surface charge density of SiC and TiC particles are established. It is shown that the adsorption of poly(ethylene oxide) (PEO) on these surfaces does not depend on pH over a wide range of pH values (4.0–11.6), has no effect on the surface charge density, and causes a considerable decrease in the electrokinetic potential of the particles owing to the shift of the shear plane towards the solution. The calculated “electrophoretic” thicknesses of PEO adsorbed layers are in good agreement with the dimensions of the end tails of adsorbed macromolecules estimated from the Scheutjens-Fleer theory of polymer adsorption.