Ultrastrong and tough paper structure from densified hybrids of multiscale cellulose fibers.

Replacing petrochemical plastics with sustainable materials requires strategies that combine high mechanical performance with low environmental impact. Here, we report an ultrastrong and tough cellulose paper created by integrating multiscale cellulose materials to overcome the weak fiber-to-fiber adhesion found in conventional paper. Bacterial cellulose microgels fill microscale voids between pulp fibers, while bacterial cellulose nanofibers reinforce nanoscale gaps, forming densely bonded interfaces through capillary-driven assembly during dehydration. This hybrid structure significantly enhances interfacial interactions and hydrogen bonding, producing cellulose paper with isotropic tensile strength of 811 MPa and robust wet-state performance. The process is highly energy-efficient due to rapid dewatering, consuming far less energy than nanocellulose-paper manufacturing. The resulting material also exhibits strong adhesion to hydrophilic substrates, expanding its application potential. By bridging the performance gap between natural cellulose fibers and traditional paper, this work provides a biodegradable, energy-efficient alternative to plastics for sustainable structural and packaging applications.