Ultrastrong and Superinsulative Aramid Aerogel Fibers Featuring Hydrogen/Covalent Bond-Interlocked Topological Networks Constructed via Freeze–Thaw Cycling

Lightweight, nanoporous aerogel fibers are core materials for thermal management textiles and triboelectric nanogenerators in extreme environments. However, their poor mechanical properties make them susceptible to structural collapse under shear or compressive stress during processing or use. To address this, we constructed a controlled hydrogen/covalent bond-interlocked topological dual-network structure within the aramid nanofibers (ANFs) skeleton. The resulting ANFs/PVA/boric acid (APB) aerogel fibers exhibit significantly enhanced tensile strength (9.8 MPa, a 180% increase over pure ANF aerogels at 3.5 MPa), remarkable shear resistance (withstanding radial pressure ∼100,000 times their own weight without significant deformation), and excellent thermal insulation (specific surface area: 181.65 m²/g; thermal conductivity: 0.0395 W/(m·K)). APB maintains exceptional thermal insulation and flexibility even at cryogenic temperatures (-196 °C). Furthermore, vacuum impregnation with polyethylene glycol (PEG) yielded APB-PEG fibers with a phase change latent heat of 142.8 J/g. Composite fabrics woven from APB and APB-PEG fibers demonstrated significantly delayed heat release. This work provides a theoretical and material foundation for developing lightweight, high-strength, multifunctional thermal insulation textiles with significant potential for personal thermal comfort, extreme environment protection, and aerospace applications.