The top layer of human skin, the stratum corneum (SC), plays an essential role in the hydration and the adhesive properties of the skin and, subsequently in its tribological behaviour 1, 2). SC comprises a thin bi-phasic layer of 10-20 cells with an average thickness between 25-200 mm depending on the body site. It is commonly described in the literature as a brick and mortar structure because is comprised of brick regions, the corneocytes, surrounded by a mortar phase of fatty acids, ceramides, cholesterol and water 4, 5). The surface of the SC is coated with a film, the Skin Surface Lipid Film (SSLF), a mixture of sebum from the sebaceous glands and lipids secreted by keranocytes. The SSLF is composed of triglycerides, squalene, wax esters and ceramides 5-7). The proportions of these components are known yet, there is inter-individual variability and also variations depending on the body site 8, 9). Epidermal lipids are mainly composed of fatty acids in forms of mono-, di-or triglycerides 10, 11) such as, Palmitic, Palmitoleic, Stearic, Oleic and Linoleic acids 11, 12). The characteristic structure of the SC and the composition of the SSLF provides rigidity to the membrane and prevents the skin dehydration 6, 13, 14). An alteration in the chemical composition or amount of the saturated and unsaturated lipids from SSLF results in an increase of the Trans Epidermal Water Loss (TEWL) with further modifications of the interfacial and mechanical properties of the SC 15-18). In the literature, changes in the physic-chemical properties of the SSLF have shown a reduction of the SC s barrier functions after tape stripping experiments 19-21). Therefore, the composition of the SSLF seems to have a role in the adhesive and mechanical properties of the SC and, consequently, in its frictional performance 22-27). Attempts to synthesize an artificial SSLF to mimic the adhesive properties of the skin have been performed previously 28-30). A pseudo-sebum based on a mixture of nine saturated and
