Thermal radiation shielded, high strength, fire resistant fiber/nanorod/aerogel composites fabricated by in-situ growth of TiO2 nanorods for thermal insulation

• Vertically aligned TiO 2 nanorods were synthesized directly on the surface of microfibers by in-situ growth. • A novel ‘fiber/nanorod/aerogel’ composite was constructed for thermal insulators. • The composite with low thermal conductivity exhibited significantly enhanced infrared radiation shielding. • In-situ growth of TiO 2 nanorods reduced the gaseous conductivity by increasing the interfacial adhesion force. Fiber/aerogel composites attract considerable interest as thermal insulation materials due to their low thermal conductivity. However, in practice they deliver unsatisfactory performance due to their high infrared radiation transmittance and poor interfacial adhesion. Herein, we report a simple strategy for constructing vertically aligned 1D rutile TiO 2 nanorod arrays (TiO 2 -NRAs) directly on the surface of quartz fibers (QFs) by in-situ growth. A novel ‘fiber/nanorod/aerogel’ composite was synthesized by filling the pores of QF/TiO 2 -NRAs with SiO 2 -Al 2 O 3 aerogels (ASAs) through vacuum impregnation. The QF/TiO 2 -NRAs/ASA composite exhibited excellent thermal insulation (0.071 W·m −1 ·K −1 at 1100 °C), infrared radiation shielding performance (an extinction coefficient greater than 150 cm −1 and an infrared reflectivity greater than 95%), fire resistance (more than 1200 °C), and compressive strength (0.37 MPa, 10% strain). In-situ growth of TiO 2 -NRAs can reduce the gaseous thermal conductivity by increasing the interfacial adhesion force between fibers and aerogels, and reduce the radiation heat transfer by shielding infrared radiation. This strategy is applicable to multi-type fibers reinforced silica-based aerogel materials used for insulation and protection in extreme environments.