Journal of Colloid and Interface Science, Vol.176, No.1, 86-94, 1995
Adsorption of Polyampholytes on Polystyrene Latex - Effect on Colloid Stability
The interfacial characteristics of low-charge-density polyelectrolytes and polyampholytes synthesized by a microemulsion polymerization technique have been investigated. Terpolymers of acrylamide (AM, neutral segment), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT, positively charged segment), and sodium 2-(acrylamido)-2-methyl propanesulfonate (NaAMPS, negatively charged segment) and copolymers of AM and MADQUAT as well as of MADQUAT and NaAMPS were adsorbed on a negatively charged polystyrene latex. The zeta potential at full surface coverage was determined and analyzed as a function of the surface charge excess of the colloid-polymer complex. The domains of colloidal instability were determined and the rate of destabilization was studied for the different systems at the optimum flocculation concentration. A deviation from the usual polyelectrolyte behavior was found for the copolymers and the terpolymers, which may be attributed to the reversible character of the aggregation processes resulting from a progressive modification of the characteristics of the adsorbed layer.
Keywords:PROVOKED CLUSTER FRAGMENTATION;ADSORBED MACROMOLECULES;STRUCTURAL RELAXATION;LIMITED AGGREGATION;MODES;MICROEMULSIONS;PARTICLES;MOBILITY;KINETICS;SYSTEMS