Physicochemical investigation on the bulk and surface properties of the binary mixtures of N-methyl-N-dodecanoyl sodium glycinate (SDDS) and N-methyl-N-decanoyl glucamine (MEGA 10) in aqueous medium

•Study of micelle formation of nonionic Mega-10 and anionic SDDS surfactants.•Evaluation of interfacial and thermodynamic properties of the micellization process.•Determination of aggregation number and micropolarity.•Circular dichroism spectra of individual as well as in mixed micelle.•Theoretical approach of mixed micelle.

Self-aggregation of nonionic N-methyl-N-decanoyl glucamine (MEGA 10) and anionic N-methyl-N-dodecanoyl sodium glycinate (SDDS) have been investigated by different physical methods such as tensiometry, conductometry, microcalorimetry, spectrophotometry, fluorimetry and circular dichroism throwing light on both bulk and interfacial behaviours of the micellar systems. The counter-ion binding, surface excess quantity, head group area have been evaluated. The thermodynamic parameters of the micellization process have been calculated, reported and discussed. The aggregation numbers and micropolarity have also been determined. Both surfactants individually as well as in mixed condition show circular dichroism spectra which are quite uncommon in the literature with respect to mixed micelle. The different experimental results have been analyzed in the light of the theories of Rubingh, Maeda and Rosen, and the overall shapes of the mixed micelles have been predicted from the estimation of the amphiphile packing parameter.