Influence of Metallic Ions on the Aggregation of Soft Colloidal Polysaccharides

The aggregation behavior of carboxymethyldextran, a soft and anionic polysaccharide, was studied in the presence of divalent cation Cd 2+ in aqueous NaNO 3 electrolyte. The experimental destabilization conditions of this colloidal suspension have determined by turbidimetric method and the kinetics of aggregation and the characteristics of aggregates were analyzed through Dynamic Light Scattering measurements. The aggregates are derived from very attractive interactions, which are modulated by the metallic ion to carboxymethylextran ratios and their feature indicates a mechanism characterized by a diffusion-limited aggregation.