ADSORPTION OF HYDROLYZED POLYACRYLAMIDES ON FERRIC-OXIDE PARTICLES - COUNTERION MOBILITY IN STABILIZED SUSPENSIONS

Adsorption isotherms and adsorbed layer thicknesses were determined as a function of polymer charge density for three samples of partially h ydrolyzed polyacrylamide on beta-ferric hydrous oxide particles. The a mount adsorbed was found to decrease with increasing polymer charge de nsity. Equal values of the hydrodynamic adsorbed layer thickness were measured by electric light scattering, whereas the average layer thick nesses, calculated according to R. Varoqui theory, were found to decre ase with increasing polymer charge density. Information on counterion mobility was obtained by means of frequency-domain electric light scat tering. The results observed are discussed in terms of counterion bind ing to polyelectrolytes of low charge density. (C) 1997 Academic Press .