Synergistic strategy of Nano-ZnO/DOPO/fluorinated silicone in waterborne polyurethane coating for multifunctional finishing of hemp fabric

Amid ongoing innovation in functional textiles, single-function materials, characterized by relatively limited performance profiles, increasingly fall short of the diverse, integrated functional demands encountered in real-world applications. Consequently, the development of multifunctional fabrics that concurrently deliver flame retardancy, hydrophobicity, UV resistance, and antibacterial activity has emerged as a critical research frontier, bearing both substantial scientific merit and high translational potential. In this work, waterborne polyurethane (WPU) was synergistically modified through the co-incorporation of surface-functionalized nano-ZnO, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and a fluorosiloxane (HPFSi), yielding a stable, ternary-modified emulsion designated ZnO/DOPO/fluorosilicone waterborne polyurethane (ZnO/PFSiWPU). This emulsion was subsequently applied to hemp fabric via coating-based finishing. Comprehensive evaluation revealed that the treated fabric exhibits outstanding integrated functionality: a limit oxygen index (LOI) of 36.2%, confirming superior flame retardancy; a water contact angle (WCA) of 151.5° ± 2.7°, indicative of durable superhydrophobicity; an ultraviolet protection factor (UPF) of 71.21, reflecting highly effective UV shielding; and antibacterial inhibition rates of 99.6% against Staphylococcus aureus and 99.9% against Escherichia coli , demonstrating robust, broad-spectrum antimicrobial efficacy. Notably, the incorporation of modified nano-ZnO into the coating system markedly improved the fabric's antibacterial and UV-resistant performance, while concurrently enhancing its flame retardancy and hydrophobicity. This finding elucidates a synergistic enhancement mechanism mediated by nano-ZnO within the multi-component composite coating, thereby offering both conceptual insights and a theoretical foundation for the rational design and development of multifunctional, high-performance textile coatings.