Stable ZnO/SiO2 nano coating on polyester for anti-bacterial, self-cleaning and flame retardant applications

Highlights: • Facile synthesis of silica-supported ZnO on PET using zinc acetate/sodium silicate. • Stable photo-active ZnO on PET under lights and acidic media. • Superior antibacterial activities by ZnO@SiO₂ on PET fabric. • Good flame retardant properties along with suitable thermal endurance. A simple chemical in-situ synthesis method was adapted to prepare silica-supported zinc oxide (ZnO) catalyst on polyester fabric (PET) in alkali conditions. This imparted the durable photo-active ZnO catalyst on the textiles with multi-functional properties under lights and acidic media. Zinc acetate and sodium silicate as two precursors was used in ammonia aqueous solution to form ZnO@SiO₂ nanoparticles on PET fabric at 90 °C. The key characterizations of the silica-supported ZnO catalyst on the PET fabric were investigated by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) comprising mapping images and Energy Dispersive X-ray (EDX) as well as Fourier Transform Infrared (FTIR). The silica-supported ZnO perfectly controlled the size of nanoparticles (NPs), reduced their size around 28.29 nm and also protected from acid solution ($pH\cong 2$). Furthermore, silica on ZnO enhanced the photocatalytic activities of the fabric through discoloration of methylene blue stain in short time under both ambient and acidic conditions. ZnO@SiO₂ NPs also acted as thermo-catalyst on the fabric due to inherent thermal resistance of Si, considerably increased the anti-dripping properties of PET during burning. In addition, the bacterial reduction of treated fabric with ZnO@SiO₂ NPs for Escherichia coli estimated around 100%. Overall, the silica-supported ZnO catalyst improved the thermo and photo catalytic activities of the PET fabric. This renders a promising approach with good potentiality for application in different industries such as filtration, energy and electronic.