Foaming and emulsification synergies in skin mild and environmentally friendly detergents based on Gleditsia sinensis saponins

Gleditsia sinensis saponins (GS) is a biodegradable nonionic surfactant extracted from the plant pericarp. The objective of this study is to evaluate its potential for application in cleaning products in response to resource and environmental changes. Here, high-purity GS (93.92 %) was obtained through the macroporous resin adsorption technique and mixed with sodium lauroyl methylaminopropionate (LMA) to form a Gleditsia sinensis saponins- sodium lauroyl methylaminopropionate (GS-LMA) binary system. The synergistic effect was clarified by calculating the intermolecular interactions and thermodynamic parameters of the mixed micelles. The surface activity, foam stability, and emulsification characteristics were investigated to assess the detergent potential of the GS-LMA mixture. The results indicated that the formation of GS-LMA mixed micelles followed a non-ideal, spontaneous exothermic process. Furthermore, the addition of GS decreased the critical micelle concentration of the mixture while enhancing foam stability (98.34 %) and prolonging the oil–water separation time (103.11 min). The synergistic effects of foaming and emulsification enhanced the cleaning efficiency of the mixtures to 90.60 %. Further studies showed the mixture can reduce oil–water interfacial tension and form stable emulsions in various environments. This work can provide a theoretical basis for a better understanding the synergistic effects of binary surfactants and interfacial science.