3D self-supportive structures of micro/nanofiber assemblies constructed in situ in air turbulent flow fields for thermal protection at extreme conditions

Three-dimensional (3D) ceramic fiber assemblies have good application prospects for thermal protection. Solution Blow Spinning (SBS) is a simple way to produce 3D fiber assemblies by using air turbulence to construct and stack fluffy fiber layers simultaneously. However, existing research lacks the study of evolutionary laws and exploration of the related mechanisms of transforming 2D fiber assemblies into 3D. In this study, we propose a self-supportive assembly strategy that can controllably produce 3D fiber macrostructures under the impact of high-speed airflow. We revealed the assembly mechanism of 3D fiber assemblies in air turbulent flow fields using in-situ observation with a high-speed camera and finite element analysis. Finally, ceramic fiber aerogels with lamellar structure, ultra-low density (9.5 mg cm −1 ) and extremely low thermal conductivity (0.0254 W m −1  K −1 ) were obtained by calcination. The lamellar structure gives them the ability to show high compressibility up to 90 % strain and high compression fatigue resistance of 1000 cycles at 50 % strain. In addition, the aerogels have the same tensile fracture strain (23.5 %) at 1300°C as at room temperature. This work is of great significance for the development, large-scale production, and application of high-performance 3D fiber aerogels.