Thermally-enhanced nanoencapsulated phase change materials for latent functionally thermal fluid

Abstract

Phase-change materials (PCMs) have attracted numerous attentions in thermal energy storage area due to their high latent heat capacity. However, their inherently low thermal conductivity and potential leakage risk severely decrease the thermal storage efficiency. In this study, thermally-enhanced nanoencapsulated phase change materials (NEPCMs) were proposed to overcome those limitations. Through a miniemulsion polymerization approach, the n-Octadecane is encapsulated by SiO2/BN shell, which not only enhances the thermal conductivity, but also avoids the leakage problem during the phase change process. Compared with pristine PCMs, the thermal conductivity of the prepared NEPCMs was reinforced by 527% to 0.912 W m−1 K−1, which is the highest record among all the encapsulated PCMs with encapsulation ratio above 50%. The latent heat of the NEPCMs reaches 136.8 J/g with an encapsulation ratio as high as 60.4%. The thermal gravity analysis (TGA) and thermal cycling tests reveal that the nanocapsules possess excellent thermal stability and reliability. Furthermore, the NEPCMs were applied in latent functionally thermal fluid (LFTF) to enhance its thermal storage capacity. A microchannel cooling setup, with the NEPCMs/water LFTF as the coolant, was developed to evaluate the LFTF cooling performance. Compared with the pristine water, LFTF with 20 wt% NEPCMs reduced the heat source temperature by 12.1 °C at 80 W, showing their potential for the thermal management applications in electronic devices.