F Golmohammadi - Department of Chemistry, Faculty of Science, Tabiat Modares University, Tehran, Iran
H Gharibi - Department of Chemistry, Faculty of Science, Tabiat Modares University, Tehran, Iran
S Javadian - Department of Chemistry, Faculty of Science, Tabiat Modares University, Tehran, Iran
A yousefi - Department of Chemistry, Faculty of Science, Tabiat Modares University, Tehran, Iran

The aggregation behavior of anion-rich catanionic mixtures of sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonioum bromide (CTAB) was investigated in water-ethylene glycol (EG) solutions by performing surface tension, electrical conductivity, zeta potential measurements, dynamic light scattering (DLS). Different physicochemical properties such as the critical micelle concentration, degree of counterion dissociation (a), interfacial properties, aggregation numbers, morphology of aggeregates, and interparticle interaction parameters were determined. Cosolvent effects on the interactions between the tho surfactants SDS and CTAB were analyzed on the basis of regular solution theory, both for mixed monolayers at the air/liquid interface (B) and for mixed micelles (B). The interparticle interpatricle interactions were assessed in terms of cosolven effects on the micellar surface charge density and the sphere th cylindrical morphology change. The zeta potential and the size of the aggregates were determined using dynamic light scattering and confirmed the suggested models for the processes happening in each system.

anion-rich catanionic mixtures, zeta potential measurements, dynamic light scattering