Multifunctional Silica Nanotube Aerogels Inspired by Polar Bear Hair for Light Management and Thermal Insulation

Designing macroscopic, 3D porous multifunctional materials is of great importance in many fields, including energy storage, thermal insulation, sensors, and catalysis. Polar bears have hairs with a membrane-pore structure, which contributes to adaptation to harsh environments. Inspired by polar bear hair, this study reports a facile route to fabricate multifunctional silica nanotube aerogels (SNTAs) via chemical vapor deposition (CVD) of silica onto the sacrificial carbon nanoskeleton of a carbon aerogel (CA). The resulting SNTAs are not only porous, nanotubular, transparent, and lightweight but also hydrophobic, thermal resistant, mechanically robust, and machinable. Moreover, SNTAs show relatively high visible and near-infrared light transmittance and almost no ultraviolet and far-infrared light transmittance, which makes it an ideal material to provide greenhouse effects and protect human beings from an overdose of ultraviolet radiation. Multifunctional SNTAs provide an integrated solution for thermal insulation, daylighting, and UV protection applied in outer space or at high latitudes.