Large-scale additive fabrication of tough nanocellulose yarns

Nanocellulose is a promising candidate for fabricating high-performance cellulosic materials due to its extremely fine structure and excellent mechanical properties. However, converting the extraordinary properties of individual nanofibers to macroscopic fibers through large-scale preparation remains a challenge. Inspired by the staple spun yarns, herein, we demonstrate a facile and scalable strategy for continuously additive fabrication of nanocellulose yarns by twisting stacked short nanocellulose slivers. Benefiting from the wet-stretching and twisting process, the resultant yarns with tightly intertwined cellulose nanofibers (CNFs) exhibit outstanding toughness (42.9MJ m^-‍3) and fracture strain (20 %), respectively. Importantly, this approach can be extended to develop functional yarns such as fluorescent yarns, magnetic yarns, and conductive yarns. This work provides a new method for large-scale preparation of tough nanocellulose yarns for future functional materials, such as smart textiles and wearable electronics.