Tribological Properties Between Taut Hair Fibers in Wet Conditions: A New Shampoo Formulation for Eliminating Stick-Slip Friction

The study investigated the detangling performance of two shampoo formulations on hair fibers in wet conditions. Both shampoos had the same base formulation but used different types of amino-modified silicones as conditioning agents. Shampoo A, with poor detangling performance, used water-insoluble silicone, while Shampoo B, with excellent detangling performance, used water-soluble silicone. The study found that Shampoo B-treated hair exhibited smooth sliding, ideal for detangling, due to the two-layer structure of the conditioning film on the hair. This structure is formed by positively charged amino-modified silicone dissolved in water adsorbing immediately on the negatively charged hair surface, followed by the physical adsorption of coacervates on the adsorbed silicone layer. The outer coacervate layer is easily removed during sliding, resulting in low friction of the silicone layer. The findings could help in the design of shampoo formulations that can easily remove tangles during daily shampooing.