Disodium laureth sulfosuccinate (DLSS) is a very mild, sulfate-free anionic surfactant derived from lauryl alcohol ethoxylated with an average of three moles of ethylene oxide. It offers excellent foaming properties and is commonly used to help reduce the skin irritation associated with sodium laureth sulfate (SLES). The mildness of DLSS is largely due to its relatively large molecular size compared to other surfactants. As a result, it does not easily penetrate the skin, reducing the likelihood of irritation, nor does it remove the essential oils from the hair and skin. On its own, DLSS does not develop viscosity upon the addition of salt. When combined with SLES, however, it produces a formulation that is mild to both skin and eyes, offers improved foaming performance, and responds well to common viscosity enhancers such as sodium chloride or alkanolamides.
DLSS is compatible with anionic, nonionic, and amphoteric surfactants, demonstrates excellent resistance to hard water, and does not produce lime soap residues, even under conditions of extreme water hardness. It works efficiently to lower the surface tension of water, allowing it to spread and perform effectively at the surface where cleaning takes place. Additionally, its liquid form and low viscosity make it highly processable.
Disodium laureth sulfosuccinate is prone to hydrolysis in both acidic and alkaline conditions, with the reaction rate increasing at elevated temperatures. It is recommended to use this material in formulations with a pH between 5 and 7. Therefore, storage or handling outside the recommended pH range or above 40 °C is not advised, as this may lead to rapid degradation of the product.
The material is valued in cosmetic and hygiene products for its effective cleansing, lathering, and emulsifying properties, while causing only minimal skin irritation, making it suitable even for baby cleansing products. The active content of DLS is approximately 33%, though it is often mistakenly reported as 40% active, when this actually refers to 40% total solids.
