Abstract
Keratin film prepared from human hair proteins is considered a substitute device for human hair samples, to conveniently evaluate hair damage such as UV, bleach, perm, and thermal stimulations. In this study, we tried to determine if the keratin film could be used to evaluate friction and adsorption by processing commercial shampoo and conditioner products. The weight and fine structure of keratin films was little affected after these treatments. Since no peeling could be detected even if the film was rubbed with our fingers, keratin films provided resistant against mechanical and chemical stresses. Compared to that of a hair strand, the friction of keratin film could be easily measured by a KES system. The MIU value of keratin film was 7-8 fold more than that of a hair strand under our experimental conditions. The friction measurement using keratin film was also possible in a wet state as well as a dry state. Keratin film could withstand the friction measurement up to at least 20 times under both states. Interestingly, the MIU value was decreased when keratin films were treated with the shampoo and shampoo-conditioner. The degree of MIU decrease was dependent on the product used. The adsorption of Si was detected in the samples after treatment with the products containing silicon. These data suggest that keratin film will also be effective to evaluate the tactile sensation of hair.
