Ultralight and highly flexible aerogels with long cellulose I nanofibers

An aerogel obtained from chemo-enzymatically oxidized fenugreek galactomannans as a versatile delivery system

“…2(b)-(d), where the internal morphology of the aerogel appears to be formed by thin polymer layers tightly stacked on top of one another. The thickness of each sheet is estimated to be below 1 m. This 2D sheet-like skeleton structure was previously reported for aerogels obtained from cellulose nanofibers (Chen, Yu, Li, Liu, & Li, 2011;Melone et al, 2013) and is assumed to be associated to the freeze-drying protocol.…”

Amphiphilic superabsorbent cellulose nanofibril aerogels

“…The CNF aerogels are amphiphilic, absorbing 210 and 375 times water and chloroform, respectively, far superior to any previously reported cellulose aerogel. 20,37,38 Further modication with triethoxyl(octyl) silane turns some hydrophilic portions of the amphiphilic aerogel hydrophobic and oleophilic, capable of absorbing 139-356 times non-polar hydrocarbons, polar aprotic solvents and oils, surpassing all previously reported polymeric, cellulosic and carbonaceous aerogels by 2 to nearly 20 times.…”

Super water absorbing and shape memory nanocellulose aerogels from TEMPO-oxidized cellulose nanofibrils via cyclic freezing–thawing

“…36 Instead of the amorphous or cellulose II structure from dissolution, 18,23 supercritical or freeze drying of aqueous nanocellulose suspensions has the advantage of retaining the native cellulose Ib crystalline structure. [30][31][32] These nanocellulose aerogels have similar specic surface areas (10- strength. These additional crosslinking and gelation processes demand extra chemical and energy inputs.…”

“…4,7,11,13,[26][27][28][29][30][31][32][33][34] Aerogels prepared from cellulose solutions require lengthy, multiple steps of dissolving cellulose in solvents, such as alkali hydroxide/urea solution, 18 calcium thiocyanate tetrahydrate, 19 N-methyl-morpholine-N-oxide, 20,21 sodium hydroxide, 22 lithium chloride/dimethylacetamine, 23 lithium chloride/dimethyl sulfoxide 24 and ionic liquid, 25 followed by induced gelation, solvent exchange and supercritical or freeze drying. Aerogels from dissolved cellulose had a specic surface area as high as 404 m 2 g À1 , 17 less than half of that of the typical silica aerogels (over 1000 m 2 g À1 ), 35 and densities ranging from 20-200 mg cm À3 , 19,20,22 one to two orders of magnitude higher than those of the silica aerogel (2-3 mg cm À3 ).…”