Silver Ion-Chelated Waterborne Polyurethane Based Antibacterial Cotton Fabric via Coordination-Driven Immobilization

: This research employed triethylenetetramine as a chelating agent to successfully synthesize a chelating-functional waterborne polyurethane (CWPU) dispersion by adjusting the ratio of hard and soft segments and optimizing the molecular structure through the use of a chain extender. This allowed for the establishment of a stable WPU/Ag composite emulsion system upon the addition of silver nitrate, and during the film formation process, the reducing properties of polyols were employed to in situ reduce Ag⁺, resulting in the formation of silver nanoparticles (AgNPs). Structural characterization analyses, including FTIR and XRD, verified that the reduced AgNPs were evenly distributed in the WPU matrix, and SEM observations revealed the presence of reduced AgNPs on the film. Further, contact angle and TG tests were performed to explore the impact of AgNPs on the hydrophilicity and thermal stability of the film. By applying WPU/Ag to cotton fabric through a padding finishing technique, the fabric retained a breathability of over 64.7% and mechanical properties exceeding 70.9%. Following 20 standardized washes, the antibacterial efficacy against Escherichia coli and Staphylococcus aureus remained above 99%. Even after undergoing 1200 abrasion tests, the antibacterial efficacy for both bacteria was sustained at over 93%, and the antibacterial rate continued to exceed 99% after a 6 h immersion in hot water. These findings suggest that the composite material possesses outstanding thermal stability, durability, and mechanical characteristics. This research offers a new methodology for the development of textiles that combine both usability and prolonged antibacterial efficacy.