Multifunctional Macrofibers via Wet Spinning: Integrating Antibacterial, Flame-Retardant, and UV Shielding Properties Using Multinetwork Cellulose-Based Aqueous Colloids

Wet spinning of nanocellulose in purely aqueous systems for functionalized filament formation represents a significant yet challenging research frontier. This study develops a sustainable wet-spinning approach to produce high-performance macrofibers using TEMPO-oxidized bacterial cellulose nanofibers (TOBCN), sodium alginate (Alg), and metal-phenolic networks (MPNs). The system utilizes Fe³⁺-mediated cross-linking in MPNs combined with Ca²⁺-induced ionic bonding with TOBCN to achieve enhanced mechanical properties. The optimized Alg/TAFe₁-TOBC₂ fiber demonstrates remarkable multifunctional characteristics, including photothermal antibacterial efficacy exceeding 99% against both Escherichia coli and Staphylococcus aureus, superior flame retardancy with 61.05% lower heat release compared to cotton, and excellent UV protection with UV protection factor values surpassing 100, which exceed standard textile requirements. The purely aqueous processing and biomass-based composition ensure environmental compatibility and biocompatibility. These macrofibers hold promise for protective textiles, combining sustainability with high performance.