Sweat effects on the thermal analysis of epidermal electronic devices integrated with human skin

Epidermal electronic devices (EEDs) are widely used in many applications especially directly integrated with human skin tissue to monitor the vital signs of human body. The thermal management of EEDs is very critical because the excessive temperature increase may cause discomfort or damage to human skin. Sweating can also significantly change the thermal environment of EED/skin system due to its function on the thermal transport process. A three-dimensional heat transfer analytical model is established to predict the thermal characteristics of EED/skin system considering the bio-heat transfer and effects of sensible sweat. In this model, the heat conductions in EEDs and in human skin are taken into account with Fourier heat transfer equation and Pennes bio-heat transfer equation, respectively, including the transport process of sweating. The results are validated by finite element analysis (FEA) and parameters studies such as velocity of sweat, thermal conductivity and thickness of substrate have been investigated. The results can help guide the thermal management of EED/skin system considering effects of sensible sweat.