Cellulose-Induced Orientation Engineering for Strong and Tough Wet-Spun PVA Filaments

Achieving a balance between high strength and toughness in biodegradable polymer fibers such as poly(vinyl alcohol) (PVA) remains a major challenge in sustainable materials design. Notably, TEMPO-oxidized cellulose nanofibers (TOCNF), featuring high aspect ratio, abundant surface hydroxyl and carboxyl groups, and excellent sustainability, serve as efficient reinforcing elements by constructing dense hydrogen-bonding networks and facilitating effective stress transfer. Here, we fabricated PVA/TOCNF composite fibers via wet spinning using a dimethyl sulfoxide (DMSO)–water mixed coagulation bath, which optimizes solubility and spinning viscosity. The synergistic combination of TOCNF–PVA hydrogen bonding and chain alignment during spinning significantly enhanced the mechanical properties. The resulting fibers exhibit remarkable ductility (elongation at break of 442.5%) and high tensile strength (131.4 MPa in the dry state and 3.12 MPa in the wet state) within an ultrashort coagulation bath residence time (∼4.57 s in total). Compared with pure PVA fibers, their dry and wet tensile strengths increased by 406% and 165%, respectively, effectively mitigating the drastic loss of strength under wet conditions. These biocompatible and biodegradable composite fibers provide a materials-design strategy for developing next-generation sustainable and flexible fibrous systems, with potential relevance to wearable and biomedical applications.