Investigation on the phase behaviors of aqueous surfactant two-phase systems containing Alkyl polyglucosides (APG) and alkyl polyglucoside sulfosuccinate (APGSS)

The surfactant aqueous two-phase systems have been widely attention because of their mild conditions and easy recovery. The phase behaviors and formation mechanism of an aqueous surfactant two-phase system (ATPS), which was composed of a nonionic surfactant Alkyl polyglucosides (APG) and an anionic surfactant sodium alkyl polyglucoside sulfosuccinate (APGSS), were studied. The phase diagram for APG/APGSS ATPS was illustrated. Merchuk relation was used to correlate the binodal experimental data. Indicating that top phase is APG enriched phase and the bottom phase is APGSS enriched. By measurements of surface tension, electrical conductivity, density, viscosity, transmission electron microscopy, and dynamic light scattering, micelle aggregation behaviors were explored. The formation mechanism of the ATPS was also proposed, which is attributed to the different aggregation behaviors between APG and APGSS molecules leads to different micelle size and morphology. The top phase flocculates due to the presence of asymmetric larger wormlike aggregates, lead to phase separation and the formation of the ATPS.