Coacervate Formation Behavior and Lubrication Properties of a Hair Shampoo Formulated With Amino Acid Surfactants and Cationized Cellulose

Coacervates are ion complexes that enhance the lubrication of hair surfaces during hair washing. In this study, hair shampoos containing typical amino acid surfactants, including sodium lauroyl methylaminopropionate, were prepared to demonstrate their coacervate formation behavior and lubrication properties. Sodium lauroyl methylaminopropionate outperformed the common amino acid surfactants sodium lauroyl aspartate and sodium methyl lauroyl taurate in terms of coacervate formation. Furthermore, the addition of sodium lauroyl methylaminopropionate reduced the kinetic friction coefficient on the wet hair surface. This interfacial phenomenon is due to the change in the amount of coacervate adhered to the hair surface. These findings are useful for fabricating hair shampoos with low irritation to the human body and excellent lubrication performance.