ZnO functionalized paraffin/diatomite phase change material and its thermal management mechanism in PDMS coatings.

The functionalization of conventional diatomite/paraffin phase change materials is of great significance to expand its application in thermal management. Herein, a nano-ZnO functionalized paraffin/diatomite phase change material (PA/F-DE/ZnO) with enhanced thermal conductivity, anti-leakage and UV-adsorption was prepared by simple melt blending and adsorption. The results indicated that when nano-ZnO was introduced to PA/F-DE (mass ratio is 1 : 1) system, the obtained PA/F-DE/ZnO not only possessed enhanced thermal conductivity and reduced leakage but also presented excellent UV absorption performance and retained the heat storage performance well. The thermal conductivity of PA/F-DE/ZnO (with 10 wt% of ZnO) is enhanced by 87.73% compared with that of PA/F-DE and exhibit high enthalpy of 76 J kg. Finally, a thermal management PDMS-PA/F-DE/ZnO film was constructed by combined 5 wt% PA/F-DE/ZnO with Polydimethylsiloxane (PDMS). The surface temperature of PDMS-PA/F-DE/ZnO film was 5-6 °C lower than that of PDMS film in the heating temperature range from room temperature to 60 °C, indicating a cooling performance and good thermal stability. The PDMS-PA/F-DE/ZnO showed an outstanding cooling for the exothermic computer and phone and usability of the phone in cold conditions. The multiple heat weakening transfer mechanisms such as thermal absorption of PA and thermal reflection of F-DE/ZnO were proposed.