A superelastic aerogel with fast shape recovery performance from large compressive strain is highly desired for numerous applications such as thermal insulation in clothing, high-sensitive sensors, and oil contaminant removal.

Fabrication of superelastic cellulose nanofibrils (CNF) aerogels is challenging as the CNF can assemble into non-elastic sheet-like cell walls.?

Here, a dual ice-templating assembly (DITA) strategy is proposed that can control the assembly of CNF into sub-micrometer fibers by extremely low temperature freezing (–196 °C), which can further assemble into an elastic aerogel with interconnected sub-micron fibers by freezer freezing (?20 °C) and freeze drying.?

The CNF aerogel from the DITA process demonstrates isotropic superelastic behavior that can recover from over 80% compressive strain along both longitudinal and cross-sectional directions, even in an extremely cold liquid nitrogen environment.?

The elastic CNF aerogel can be easily? modified by chemical vapor deposition of organosilane, demonstrating superhydrophobicity (164° water contact angle), high liquid absorption (489 g g?1 of chloroform absorption capacity), self-cleaning, thermal insulating (0.023 W (mK)?1), and infrared shielding properties.

This new DITA strategy provides a facile design of superelastic aerogels from bio-based nanomaterials, and the derived high performance multifunctional elastic aerogel is expected to be useful for a wide-range of applications.

Tremendous amounts of effort have been exerted on improving the mechanical properties of the aerogel, primarily focusing on enhancing the compressibility and elasticity performance.

Elastic aerogels, due to their high resilience, elasticity, and shape-recovery performance, have been actively researched, as the ability to recover from large compressive strain is essential for various applications such as electrical signal sensing,water treatment,thermal and acoustic insulation,air filtration,and energy storage.

?Lately, nanocellulose, especially cellulose nanofibrils (CNF), has been widely used to construct aerogels with a high specific surface and excellent mechanical properties.?

CNF aerogel with various densities (2.2–20.2 mg m?3) and porosities (99.8–98.7%) can be assembled by tuning the initial sub-micron CNF fiber concentrations from 0.2 to 2 wt% .