Adsorption of poly (diallyl-dimethyl-ammoniumchloride) (PDADMAC) and of copolymers of DADMAC with N-methyl-N-vinyl-acetamide (NMVA) on colloidal silica
2008; Linguagem: Inglês
10.1007/bfb0118168
AutoresDavid W. Bauer, E. Killmann, Werner Jaeger,
Tópico(s)Electrostatics and Colloid Interactions
ResumoThe adsorption of cationic polyelectrolytes on colloidal silicaparticles is investigated. The adsorbed amounts and hydrodynamic layer thicknesses of the cationic polyelectrolytes poly(diallyl-dimethyl-ammoniumchloride) PDADMAC of different molar masses and statistic copolymers of DADMAC and N-methyl-N-vinyl-acetamide (NMVA) of various contents have been measured. Furthermore, the surface charge densities of the bare and polyelectrolyte covered silica particles have been determined by potentiometric titration. The adsorbed amounts as well as the hydrodynamic layer thicknesses of the adsorbed polyelectrolyte layer increase with the ionic strength and the pH of the suspension and at high salt concentration with the molar mass of the macroions. At low salt concentrations the adsorbed amounts rise with decreasing charge density of the polyelectrolyte. During polyelectrolyte adsorption the surface charge density of colloidal silica is increased because of the dissociation of silanol groups.
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