Knittable, thermally insulating, and sustainable aerogel fibers enabled by ion-mediated hierarchical assembly

Aerogel fibers (AFs), while promising for personal thermal management, are constrained by an inherent trade-off between mechanical robustness and thermal insulating performance. To resolve this mechanical-thermal coupling issue, we propose an ion-mediated attenuated Coulombic assembly of recyclable heterocyclic aramid nanofibers (HANFs) to construct hierarchical AFs, enabling programmable manipulation of pore size and porosity. HANF-AF features a dual-scale porous architecture, comprising a nano-porous core and a macro-porous cellular shell, which encloses interconnected nanofiber spacing with sub-50 nm pores. The hierarchically porous architecture and strong crosslinking endow HANF-AF with a synergy of tensile strength up to 83.1 MPa and thermal conductivity down to 22.0 mW·m-1·K-1. Their robustness enables knitting into an industrial-grade textile with superior insulating features over conventional thermal insulating fibers. By leveraging ion-mediated hierarchical assembly of recycled nano-building blocks, this work establishes a scalable and sustainable strategy for engineering multifunctional nanofibrous architectures, offering a blueprint for creating next-generation flexible, durable, and superinsulating materials for advanced thermal management. Aerogel fibers face intrinsic trade-offs between mechanical robustness and thermal insulation. Here, the authors report ion-mediated, attenuated Coulombic assembly of recyclable heterocyclic aramid nanofibers to programmatically control hierarchical pore structure achieving high tensile strength and ultralow thermal conductivity.