High Performance Sulfate-Free Cleansers: Surface Activity, Foaming, and Rheology

Recently, consumers have made a giant push for more sustainable and natural products to be used in the personal care product industry. A majority of body washes contain Sulfate-based and other types of synthetic surfactants, which are the main materials used for cleansing. In order to develop a sulfate-free body wash with increased naturality, the main change must come from the surfactant system involved. A new combination of surfactant system, consisting of alkyl olefin sulfonate (AOS), alkyl polyglucoside (APG) and lauryl hydroxysultaine (Sultaine), was evaluated to determine its efficacy in a variety of parameters. Specifically, the effect of APG concentration and sodium chloride concentration were measured. A tensiometer was utilized to test surface tension, a foaming study was conducted, and a rheometer was used to test mechanical rheological properties, such as viscosity and moduli frequency response. A synergistic effect was seen between AOS and Sultaine, producing a minimal surface tension value, an effective foam-ability, and a high viscosity and viscoelasticity. However, the substitution of AOS with the more sustainable surfactant, APG, resulted in the disruption of the microstructure, a decrease in viscosity and an increase in surface tension. It can be concluded that the AOS/Sultaine system is more optimal compared to an APG/Sultaine system, while it is still sulfate-free & can be more sustainable. All of these properties are desirable, proving this system to be a viable, sulfate free alternative cleansing system with increased naturality.