An in vivo methodology for studying the interfacial interactions between skin and hair with respect to tactile friction and sensory properties

With the increasing of quality of life, consumer's expectations on high value products are not only on functionality and usability, but also on emotional characteristics. In this work, we developed an in vivo methodology, based on a self-assembled finger friction test apparatus and systematical influence factor investigation, for studying the interfacial interactions between human skin and hair, with respect to tactile friction and sensory properties of human hair bundles before and after using hair care products. It was found that, the tactile friction reduced with the increasing of normal load and product usage. Backward sliding showed higher tactile friction than forward sliding mode. Damaged hair exhibited lower tactile friction than virgin hair under wet situation, while showed higher tactile friction than virgin hair under dry situation. The developed methodology has been used preliminarily to investigate the tactile friction of hair after using several well-designed hair care products.