Bifunctionalization of cotton textiles by ZnO nanostructures: antimicrobial activity and ultraviolet protection

Zinc oxide (ZnO) nanostructures were in situ synthesized on the surface of cotton fabric via a simple wet chemical route for providing antimicrobial activity and ultraviolet (UV) protection. Surface morphology and surface chemistry were characterized by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy. Antibacterial activity was evaluated against Gram-negative Klebsiella pneumonia and Gram-positive Staphylococcus aureus bacteria. UV-blocking ability was investigated by measuring the ultraviolet protection factor (UPF) value in the range of 280-400 nm according to AATCC Test Method 183-2004. SEM images revealed that significant amounts of hierarchical ZnO nanostructures were homogenously formed on the fibers' surface; most of them are bundle/flower-like particles having different sizes. Antibacterial tests showed that the ZnO-coated fabric possesses good bacteriostatic activity against two representative bacteria, demonstrated by the zone of inhibition. However, there was no reduction in the number of bacteria, proving the lack of bactericidal activity. The UPF value of the ZnO-coated fabric was increased to 105.61, which demonstrate its excellent ability to block the UV radiation. The washing durability was also confirmed by performing repeated home laundering.