In vivo friction study of human skin: Influence of moisturizers on different anatomical sites

In order to understand the human haptic system, the mechanical characterization of skin contact is an important task. As the skin constitutes itself a surface. it is convenient to describe the problem using a contacting surface analysis, especially concerning the friction which occurs when the skin interacts with other surfaces. Several published works have shown that the analysis of the friction response of the skin can provide an indirect way to assess the skin condition. The present study uses a new approach to evaluate in vivo the human friction measured by direct sliding action with an increase of the normal load. Two moisturizer ointments, petrolatum and glycerin, were applied in two anatomical sites of the individual submitted to this study. In order to evaluate hydration effects, this study also incorporates a direct characterization of the moisture content measuring the transepidermal water loss (TEWL). The effect of the moisturizers as a function of time after the application was studied for different anatomical sites. The normal compression and the tangential forces were measured using a three-dimensional force sensor while slipping the skin over a spherical glass surface. The skin hydration was concomitantly monitored by measuring the TEWL. (C) 2007 Elsevier B.V. All rights reserved.