Continuous Fabrication of Bioinspired All-Biomass Aerogel Fibers for Thermal Insulation

Aerogel fibers have been considered as a promising solution for thermal protection textiles due to their high porosity and low thermal conductivity. However, the scalable production of sustainable and mechanical strong aerogel fibers remains a critical challenge. Here, inspired by the porous core-shell structure of polar bear hair, we report a continuous strategy to fabricate all-biomass aerogel fibers featuring an encapsulated core-shell architecture using silk fibroin as the core and cellulose as the shell. This tunable structure, with radially aligned sheet-like pores and adjustable shell thickness, is achieved through hydrogen bond-driven cellulose contraction and alcohol-induced curing of sheet-like silk fibroin. Such a porous architecture effectively suppresses convective heat transfer and promotes a multi-reflective effect for infrared radiation. The resulting fibers exhibit good mechanical robustness with a tensile load of a single aerogel fiber is up to 200 g without reinforcement. Meanwhile, the aerogel fiber maintains high porosity (79.78%), low thermal conductivity (52.4 ± 4.2 mW m^-1 K^-1), and low density (0.193 ± 0.01 g cm^-3). Furthermore, an aerogel glove fabricated from these fibers demonstrates good thermal insulation. These results provide new insights for the design of biomimetic aerogel fibers with core-shell architecture, offering a scalable and eco-friendly pathway toward advanced wearable thermal management.