Abstract: The interaction between sodium polystyrenesulfonate(NaPSS) and N,N-dimethyldodecylamine oxide (DDAO) micelles with different concentrations was studied by using turbidimetry, dynamic light scattering, and electrophoretic light scattering. While the interaction was controlled by ionic strength, the micelle concentration shows no effect on the interaction. Dynamic light scattering reveals that the binding of DDAO micelles to NaPSS occurs at a degree of micelle ionization ft prior to critical degree of micelle ionization, β_c, which was obtained from turbidimetric titration. The critical micelle surface charge density at a point where micelles associate with polyelectrolyte has a difference of 15% for calculation using β₁and β_c. Arapid change in the electrophoretic mobility of the system is also observed in the vicinity of ionization degree of micelles corresponding to β₁in the dynamic light scattering.

Key words: N, N-Dimethyldodecylamine oxide micelle, Sodium poly (styrene-sulfonate), Dynamic light scattering, Turbidimetry titration, Electrophoretic light scattering