When nano-fillers are used to enhance the thermal conductivity of organic phase change materials (PCMs), the naturally formed interface is considered to hinder thermal transport of the composite PCMs. However, the effect of the interface on the thermal properties of surrounding PCM has not been fully studied. In this paper, three composite PCMs (Ery@SiC, Ery@SiO₂ and Ery@Si₃N₄) were prepared by melt-blending method. The local thermal conductivity and reduced Young’s modulus (E*) of the erythritol at the interface and far away from the interface in the composite PCMs were simultaneously measured by scanning thermal microscopy (SThM). The results revealed significant enhancement in local thermal conductivity of erythritol at the interface and its obvious positive correlation with E*. For different composite PCMs, molecular dynamics (MD) simulations suggested that the increase in intrinsic thermal conductivity and E* of erythritol is attributed to the increase in interaction energy between erythritol and nanoparticles, as more erythritol phonon vibrations transform from localized mode to delocalized mode and erythritol has a higher density at the interface. These findings will provide new ideas for the design of PCM for energy storage.

The revelation of thermal energy exchange mechanism of human body is challenging yet worthwhile, because it can clearly explain the changes in human symptoms and health status. Understanding, the heat transfer of the skin is significant because the skin is the foremost organ for the energy exchange between the human body and the environment. In order to diagnose the physiological conditions of human skin without causing any damage, it is necessary to use a non-invasive measurement technique by means of a conformal flexible sensor. The harmonic method can minimize the thermal-induced injury to the skin due to its low heat generating properties. A novel type of computational theory assessing skin thermal conductivity, blood perfusion rate of capillaries in the dermis, and superficial subcutaneous tissues was formed by combining the multi-medium thermal diffusion model and the bio-thermal model (Pennes equation). The skins of the hand back of six healthy subjects were measured. It was found that the results revealed no consistent changes in thermal conductivity were observed across genders and ages. The measured blood perfusion rates were within the range of human capillary flow. It was found that female subjects had a higher perfusion rate range (0.0058–0.0061 s⁻¹) than male subjects (0.0032–0.0049 s⁻¹), which is consistent with invasive medical studies about the gender difference in blood flow rates and stimulated effects in relaxation situations.