Ambient Drying Fabrication of Aramid Aerogel Fibers via Customizing Solid-Liquid Interface and Skeletal Strength

Aerogel fiber is considered as outstanding thermal insulation and flexible material for next generation thermal management. However, conventional Supercritical Drying and Freeze Drying methods suffer from energy inefficiency and limited scalability. Herein, a combined solvent exchange and freeze-thaw process is developed to suppress capillary force during ambient pressure drying (by replacing water with low surface tension solvent) while enhancing pore wall strength, enabling scalable fabrication of aramid nanofiber (ANF) aerogel fibers with micron/nanometer graded pores. The resultant fibers exhibit 84.3% porosity, 269.1 m² g^-1 specific surface area, and 49.6 MPa tensile strength. Knitted textiles (80 × 15 cm) using kilometer-scale multifilament fibers are fabricated, demonstrating a sustained thermal differential >5 °C under bidirectional extremes (either a 100 °C hot plate or -4 °C outdoors) at one-third the areal density of cotton. This energy-efficient scalable manufacturing strategy enables high performance thermal management for industrial and wearable applications.