Surface-Functionalized ZnO Nanorods via PEG-Assisted Stabilization for Durable Antibacterial Lyocell Fibers

This study reports a polyethylene glycol (PEG)-assisted surface functionalization strategy to achieve colloidal stabilization of rod-shaped ZnO nanorods and their uniform integration into Lyocell fibers via dry-jet wet spinning. ZnO nanorods are prone to aggregation due to high surface energy, limiting their antibacterial efficacy. We demonstrate that PEG molecules adsorb onto ZnO surfaces through hydrogen bonding and coordination, providing steric stabilization that prevents agglomeration and ensures homogeneous dispersion in the spinning dope. The optimized composite fiber with 3 wt% ZnO exhibits balanced performance, delivering inhibition rates above 95% against Escherichia coli and Staphylococcus aureus, while retaining over 80% efficacy after 50 laundering cycles. Morphological and structural analyses confirm that PEG-mediated interfacial interactions facilitate stable nanoparticle encapsulation without disrupting the cellulose crystalline structure. Antibacterial mechanism studies further reveal that light-induced reactive oxygen species (ROS) generation is the dominant antibacterial pathway, while Zn2+ release provides a secondary contribution. In addition, the antibacterial performance remains stable under different humidity conditions (30%–80% RH), indicating good environmental robustness. This work demonstrates a scalable and eco-friendly route to fabricate durable antibacterial fibers and highlights the broader significance of colloidal stabilization and interfacial engineering in functional polymer composites.