Large-scale additive fabrication of tough nanocellulose yarns

[Display omitted] •A large-scale additive fabrication strategy was proposed to prepare tough yarns.•The nanocellulose yarns had high toughness and excellent flexibility.•The yarns could be further used in smart textiles and wearable electronics. 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 (42.9MJm-‍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.