Cold Alkali Treatment Enabled Stretchable yet Mechanically Strong All-Cellulose Composite

─1.3 times stronger, 1.5 times more stretchable, and 3.8 times tougher than microfibrillated cellulose films. With added benefits of wet strength, grease resistance, oxygen barrier property, and biodegradability, this work demonstrates a scalable approach to engineering multiscale cellulose networks for sustainable packaging.