Adsorption of poly(ethyleneglycol) and poly(amidoamine)dendrimer from their mixtures on alumina/water and silica/water interfaces

Adsorption behaviors of poly(ethyleneglycol) and poly(amidoamine)dendrimer with surface carboxyl group on alumina and silica in aqueous solutions were studied at pH 5. Poly(amidoamine)dendrimer adsorbed considerably on both alumina and silica, while poly(ethyleneglycol) adsorbed preferably on silica to alumina. In a simultaneous adsorption of poly(ethyleneglycol) and poly(amidoamine)dendrimer at a constant initial concentration of poly(ethyleneglycol), competitive effects are for poly(ethyleneglycol) at all concentrations and for poly(amidoamine)dendrimer at higher concentrations only for both alumina and silica particles. The ζ potential and sedimentation rates of the suspensions were affected by adsorption of the polymers. The adsorption mechanism of the polymers on alumina and silica was discussed.