Robust, Bio-Inspired Aramid Nanofiber Aerogels for Extreme-Condition.

The organization of porous materials assembled from nanofibers and nanosheets is difficult to capture with traditional structural parameters optimized for application. Here we show graph models describing the complex structure of porous structure, and the super-elastic aramid nanofibers aerogels are prepared. The wood-like cellular architecture combined with covalently crosslinked chemical structure, endows the structured aramid nanofibers (SANFs) aerogels with density as low as 13.0 mg cm-3, while providing an ability that can withstand 800 times its own weight in the vertical direction. An elastic compressive strain with minimal shrinkage under stress was observed even in extreme condition between 77-673 K, while fatigue resistance over 2000 times compressive cycles were observed. Benefiting from the inherited properties non-flammability, chemical stability, and excellent thermal stabilities of aramid microfibers, SANFs aerogel also display ultralow thermal conductivities (24.8 mW m-1 K-1). The combination of high thermal insulation and rational mechanical properties offers a potential material system for robust thermal superinsulation under extreme conditions.