Green Synthesis of ZnO Nanoparticles Using Ramie (Boehmeria nivea L. Gaud) Leaf Extract for Surface Functionalization of Ramie Fabrics

: The increasing demand for sustainable antibacterial textiles necessitates environmentally benign synthesis routes and efficient nanoparticle immobilization strategies. This study presents a circular plant-to-textile strategy by synthesizing ZnO nanoparticles using Boehmeria nivea (ramie) leaf extract and immobilizing them onto ramie fabrics. ZnO nanoparticles were optimized by varying solution pH and precursor concentration. The effects of solution pH and precursor concentration were optimized, with the best performance obtained at pH 8 and a 1 M precursor concentration, producing phase-pure hexagonal wurtzite ZnO with controlled crystallinity, uniform morphology, and and an elemental composition consistent with ZnO. Ultrasonic-assisted dip-coating with sodium polyacrylate enabled stable ZnO immobilization, retaining >90% of the coating after aqueous immersion. The highest ZnO loading (binder:ZnO = 1:20) produced the largest inhibition zone against Staphylococcus aureus (19.32 ± 2.23 mm) and the highest relative Zn surface content (43.1 ± 0.3 wt%, EDS). These findings demonstrate a sustainable circular ramie leaf–ramie fiber strategy for developing durable antibacterial functional textiles.