Superelastic, Hygroscopic, and Ionic Conducting Cellulose Nanofibril Monoliths by 3D Printing

Abstract

Compressible and superelastic 3D printed monoliths have shown great promise in various applications including energy storage, soft electronics, and sensors. Although such elastic monoliths have been constructed using some limited materials, most notably graphene, it has not yet been achieved in nature's most abundant material, cellulose, partly due to the strong hydrogen-bonding network within cellulose. Here, we report a 3D-printed cellulose nanofibril monolith that demonstrates superb elasticity (over 91% strain recovery after 500 cycles of compressive test), compressibility (up to 90% compressive strain), and pressure sensitivity (0.337 kPa −1 ) at 43% relative humidity. Such a high-performance CNF monolith is achieved through both hierarchical architecture design by 3D printing and freeze-drying and incorporation of hygroscopic salt for water absorption. The facile and efficient design strategy for a highly flexible CNF monolith is expected to expand to materials beyond cellulose and can realize much broader applications in flexible sensors, thermal insulation, and many other fields.

Fibrous Aerogels for Solar Vapor Generation

“…Hence, inspired by natural plant transpiration, the methods to prepare similar porous structures are attractive, wherein water transports in the vertical aligned channels of the tree trunks with low flow resistance ( Tu et al, 2020 ). The porous structures of fibrous aerogels could be prepared by different methods, including plant templating, ice templating, foaming, and 3D printing, considering various strategies to improve the performance of SVG systems ( Zhang et al, 2005 ; Deville et al, 2006 ; Li et al, 2017c ; Shao et al, 2020 ; Chen et al, 2021b ).…”

“…Three dimensional metamaterials derived from 3D printing have gained growing popularity amid various approaches. The method known as direct ink writing is useful in printing diverse sophisticated structures using colloidal gel inks such as nanocellulose, graphene, CNTs, and polymers ( Chen et al, 2021b ). The ink could be directly assembled after being extruded by needle with designed structure, which relies on the rheological properties of materials.…”

Strong, tough, ionic conductive, and freezing-tolerant all-natural hydrogel enabled by cellulose-bentonite coordination interactions

“…Among them, ionic conductive cellulose hydrogels incorporated with inorganic salt ions gained considerable attention in the field of flexible energy storage devices due to their high ionic conductivity and good freezing tolerance 12 , 13 . However, since the salt ions can easily diffuse into the semicrystalline/crystalline regions of cellulose and weaken the hydrogen-bonding interaction between the cellulose chains, a trade-off between ionic conductivity and mechanical strength was frequently observed 14 , 15 .…”

Interface effects from moisture in nanocomposites of 2D graphene oxide in cellulose nanofiber (CNF) matrix – A molecular dynamics study

“…Barthelat and colleagues showed that GO membranes can be given complex shapes in the wet state by the use of 25% of cellulosic slurries of bres 50-2600 mm in length. 27 3D printing of CNF inks is a real possibility, 28 where it should be possible to include 2D nanosheets. For CNF-GO nanocomposites, there are not so many previous studies, [29][30][31][32] whereas graphene or reduced GO have been used more frequently 30,[33][34][35][36] when high electrical conductivity is desirable.…”