Tough and Moldable Sustainable Cellulose-Based Structural Materials via Multiscale Interface Engineering

All-natural materials derived from cellulose nanofibers (CNFs) are expected to be used to replace engineering plastics and have attracted much attention. However, the lack of crack extension resistance and 3D formability of nanofiber-based structural materials hinders their practical applications. Here, a multiscale interface engineering strategy is reported to construct high-performance cellulose-based materials. The sisal microfibers are surface treated to expose abundant active CNFs with positive charges, thereby enhancing their interfacial combination with the negatively charged CNFs. The robust multiscale dual network enables easy molding of multiscale cellulose-based structural materials into complex 3D special-shaped structures, resulting in nearly twofold and fivefold improvements in toughness and impact resistance compared with those of CNFs-based materials. Moreover, this multiscale interface engineering strategy endows cellulose-based structural materials with better comprehensive performance than petrochemical-based plastics and broadens cellulose's potential for lightweight applications as structural materials with lower environmental effects. A high-performance multiscale cellulose-based structural material is constructed through a multiscale interface engineering strategy. The positive and negative charges treatment of microfibers and nanofibers effectively solves the interface bonding problem in multiscale design, and allows them to be easily shaped into complex three-dimensional special-shaped structures. This sustainable material offers superior mechanical and thermal properties compared to petrochemical-based plastics.image