Sol–Gel functionalization of cotton textiles with zinc oxide for antibacterial and non-flammable properties

Abstract Multifunctional cotton textiles with antibacterial properties and reduced flammability are highly desired for various types of protective clothing. A major challenge in their production is achieving stable and sustainable functionalization that remains effective after repeated washing. In this study, we propose a novel strategy for grafting platelet-shaped zinc oxide (ZnO) crystals onto the surface of cotton fabric using an amino–silica interface that enables strong binding of zinc cations. The fabric was first coated with a layer of (3-aminopropyl)triethoxysilane (APTES), which subsequently complexed zinc cations and mediated the deposition of ZnO on the surface. The antibacterial activity of the ZnO nanoparticle–modified cotton fabric was evaluated using the disk diffusion method against Escherichia coli (no inhibition observed), Staphylococcus aureus (inhibition zone: 25.0 ± 0.5 mm), and Pseudomonas aeruginosa (inhibition zone: 35.0 ± 0.5 mm). The modified cotton retained its antibacterial performance without any loss after five washing cycles. Flammability tests demonstrated promising behavior, with less than 2% of the material converted to ash after direct exposure to an open flame for 15 s. These findings provide a promising route for the development of durable and efficient antibacterial and flame-resistant cotton textiles based on zinc oxide nanoparticles.