Strong, Tough, Shell-Cross-Linked Aramid Nanofibrous Aerogel Fibers for Thermally-Protective Textiles

Aerogel textiles show remarkable promise for thermal protection under extreme conditions. However, challenges in the mass production of aerogel fibers and their low strength still impede practical applications. Here, we report shell-cross-linked aramid nanofibrous aerogel fibers (ScANFAFs) fabricated via a stepwise sol–gel coupled wet-spinning strategy. This strategy enables rapid gelation of the shell flow of the aramid nanofiber (ANF) sol through the fast reprotonation and cross-linking reactions of the H-lacking ANFs to form a strong and tough shell layer, while the core sol undergoes slow gelation to obtain a porous nanofibrous core layer. Given this composite structure, ScANFAFs achieve a strength of 83.2 MPa, a toughness of 15.05 MJ·m–3, high porosity (>96%), and high specific surface area (286.8 m2·g–1). The mechanical robustness of ScANFAFs meets the requirements for weaving by using an automated loom. The resulting aerogel textiles exhibit low thermal conductivity (0.032 W·m–1·K–1), excellent thermal protection over a wide temperature range, and outstanding thermal stealth capabilities in extreme cold and ambient conditions. This work points to a promising direction for the multifunctional thermal protection of aerogel fibers and textiles.