Physico-chemical characterization of mixed micellar aggregates formed by b-glucoside and sodium decylsulfate in aqueous solution

The mixing behavior of b-octylglucoside and sodium decylsulfate in aqueous solution has been studied by various experimental techniques. The critical aggregation concentration (c.m.c.) of surfactants' mixtures has been determined by surface tension measurements. The results adapt reasonably well to the regular solution model, a favorable interaction between the two surfactants being found. The aggregation number of surfactants' mixtures, obtained by fluorescence quenching measurements, varies almost regularly between those of the two surfactants. Furthermore measurements of the Electronic Paramagnetic Resonance (EPR), employing the cationic molecule TEMPO-choline as spin probe, allowed the investigation of the hydrophobicity and surfactants' packing in the mixed micelles.