Super-Robust Cellulose Rayon Filaments Engineered via Molecular Orientation-Cross-linking Assembly

Developing high-performance regenerated cellulose fibers as sustainable alternatives to nonrenewable and nonbiodegradable synthetic fibers (e.g., polyamide and polyester) remains a critical challenge, particularly in addressing the environmental concerns of conventional viscose rayon and the fibrillation issues of Lyocell fibers. This study introduces a molecular orientation-cross-linking assembly technology integrated with dry-jet wet spinning, employing a deep eutectic solvent system (ZnCl₂/formic acid/water) for efficient cellulose dissolution. Through synergistic gravity-assisted traction orientation, Ca²⁺ complexation, and ethanol-water coagulation, we achieve highly aligned cellulose chains with exceptional structural ordering (60.4% crystallinity, >0.8 orientation factor). The resulting cellulose filaments demonstrate record mechanical properties with a tensile strength of 1.02 GPa and a toughness of 44.08 MJ m^-3, surpassing commercial polyamide, polyester, Modal, and Lyocell fibers. This approach not only enables precise molecular-scale control of fiber performance but also provides a scalable and sustainable manufacturing solution.