Synopsis

The deposition, substantivity, and buildup of various formulations on the surface of untreated and oxidized hair fibers have been investigated using a combination of wettability scanning and microfluorometry. Wettability scanning along the length of the fiber establishes variations in surface nergy and thus can explore only increases in surface coverage asa result of multiple treatments. On the other hand, microfluoro-metry, which involves incorporation of appropriate fluorochromes into the formulation, can provide infor-mation about the thickness of surface deposits and thus can be used to study buildup phenomena during multiple applications. Multiple treatments with a formulation containing a cationic polymer in conjunc-tion with an anionic ethersulfate surfactant lead to buildup of surface deposits during multiple treatments. These deposits are strongly held even on unoxidized hair fibers, and repeated rinsing does not completely remove them. In contrast, a formulation containing keratin hydrolysate deposits on the scale faces of the hair surface, with no buildup in multiple applications. Deposition of this material on unoxidized fibers results in an increase in hydrophilicity of the fiber surface that appears to increase slightly with multiple treatments, possibly reflecting more uniform distribution on the surface