Gradient all-nanostructured aerogel fibers for enhanced thermal insulation and mechanical properties

Lightweight, nanoporous aerogel fibers are crucial for personal thermal management and specialized heat protection. However, wet-spinning methods, exemplified by aramid aerogels, inevitably form a dense outer layer, significantly reducing the volume fraction of efficient thermal barrier nanovoids and limiting the development of ultimate thermal resistance in fibers. Herein, we develop a microfluidic spinning method to prepare gradient all-nanostructure aramid aerogel fibers (GAFs). Benefiting from the simultaneous shear alignment and diffusion dilution of a good solvent within the channels, the precursor gel fibers assemble into a structure with a sparse exterior and dense interior, which reverses during…