Nanotribological and nanomechanical properties of skin with and without cream treatment using atomic force microscopy and nanoindentation

Various beauty care products involve surface interaction between the product and the skin surface they are applied to. Friction, adhesion and wear during sliding between the treated surface and the rubbing surfaces need to be optimized. Skin cream is used to improve skin health and create a smooth, soft, and flexible surface with moist perception by altering the surface roughness, friction, adhesion, elastic modulus, and surface charge of the skin surface. Rheology of skin cream as a function of cream thickness and strain rate and the binding interaction between skin cream and skin surface and operating environment are some of the important factors affecting the smooth feel and repair of the skin surface. Atomic force microscopy (AFM) and nanoindentation have recently become important tools for studying the micro/nanoscale properties of human hair, hair conditioner, skin, and skin cream. In this paper, we present an overview of the nanotribological and nanomechanical properties of skin with and without cream treatment as a function of operating environment. Relevant mechanisms are discussed. Next, the result of a triboelectrification study of skin with and without cream treatment is presented. Finally, an overview of attempts to develop a synthetic skin for research purposes is presented.