Yorke, Kelly, et al. International Journal of Cosmetic Science 43.6 (2021): 636-652.
The increasing demand for mild, environmentally friendly, and sulfate-free surfactant systems has highlighted the importance of lauryl hydroxysultaine (Sultaine) as a versatile amphoteric surfactant. In this study, Sultaine was employed in combination with alkyl olefin sulfonate (AOS) and alkyl polyglucoside (APG) to formulate binary and ternary surfactant systems, aiming to optimize surface activity, foaming ability, and rheological properties while eliminating traditional sulfates such as sodium laureth sulfate (SLES).
Experimental Procedure:
1. Binary system preparation: AOS and Sultaine were mixed at varying ratios (1:3, 1:1, 3:1) and dissolved in deionized water under stirring to evaluate the effect of surfactant ratio on surface tension, foaming, and viscosity.
2. Ternary system formulation: APG was introduced into selected AOS:Sultaine ratios at different concentrations (2.5-5 wt.%), and the mixtures were homogenized. Surface tension was measured using a tensiometer, while rheological properties were determined with a viscometer at multiple shear rates.
3. Salt effect studies: Sodium chloride was added in incremental concentrations (up to 2 wt.%) to both binary and ternary systems to assess the influence of ionic strength on surface activity and viscosity.
Results demonstrated that the 1:1 AOS:Sultaine binary system exhibited the lowest surface tension (26.587 mN m⁻¹) and optimal foaming performance. Addition of APG slightly increased surface tension but reduced viscosity, shifting the system toward Newtonian behavior in ternary mixtures. Salt addition modulated viscosity differently depending on system composition, without significantly affecting Sultaine alone. The study confirms that lauryl hydroxysultaine is an effective component for formulating mild, sulfate-free surfactant systems with tunable physicochemical properties, suitable for applications in personal care and household cleaning formulations.
