Enhanced thermal insulation properties of PI nanofiber membranes achieved by doping with SiO2 nanoparticles

At present, energy consumption is a worldwide topic and it is an urgent requirement for the development of energy-saving materials. Thermal insulation materials with a low thermal conductivity show a significant potential to reduce energy waste. In this study, polyimide (PI) and silica/polyimide (SiO2/PI) nanofiber membranes (NFMs) with low thermal conductivity were prepared by electrospinning. The effect of different content of SiO2 nanoparticles (SiO2 NPs) on the thermal insulation properties of PI NFMs and the thermal insulation mechanism were studied. SiO2/PI NFMs has the lowest thermal conductivity of 0.033 W/(m·K) when the content of SiO2 NPs was 2 wt%. The experimental results reveal that when the addition of SiO2 NPs was low, the dominant factor of the increasing thermal insulation is the interfacial thermal contact resistance between the SiO2 NPs and PI nanofibers. Moreover, the SiO2 NPs can improve the thermal stability and hydrophobic of SiO2/PI NFMs. This study indicates the SiO2/PI NFMs has the potential applications in thermal insulation.