UC Davis

Cellulose has been efficiently isolated from almond shell (AS) of a soft-shell Carmel variety by a two-step NaClO2 oxidation-KOH alkali protocol at over 35 % yield, then optimally TEMPO-oxidized and blended to yield 92 % and averagely 1.2 nm high (H), 5.2 nm wide (W), and 1.4 µm long (L) cellulose nanofibers (CNFs) with 58.6 % crystallinity and 1.3 mmole/g charge. With uniquely high 1167 L/H aspect ratio and 4.3 W/H lateral anisotropy, AS CNFs self-assembled into 1D fibers and 3D aerogels by freezing at − 196 °C and − 20 °C, respectively, then lyophilization as well as 2D films by air drying. All fibers were fully re-dispersable in water to individualized CNFs whereas aerogels were amphiphilic super-absorbents, absorbing slightly more hydrophobic chloroform than water, and films were hydrophilic on the surfaces and absorbed ca. three times more water than decane. The fully aqueous dispersible fibers, amphiphilic and water resilient aerogels, and organic resilient films are attributed to the interfacial associations of AS CNF driven by their uniquely high aspect ratio and cross-sectional anisotropy, demonstrating processing potential into versatile 1D to 3D materials.