Fabrication of cotton fabrics with durable antibacterial activities finishing by Ag nanoparticles

In this paper, we propose a facile and mild route to prepare size-tunable silver nanoparticles (Ag NPs) and their finishing application on fabrication of antibacterial cotton fabrics. The as-prepared Ag NPs, with an average particles size of 2.3 nm, show the minimal inhibitory concentration of 7.8 µg/mL and the minimum bactericidal concentration of 15.6 µg/mL, respectively. In this study, sodium citrate served as a stabilizing agent to prevent Ag NP agglomeration in the synthesis process, and citric acid acted as a binder to fix Ag NPs on the cotton fabrics through chemical bonds in the finishing process. The results of Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy demonstrate that Ag NPs have been fixed and well dispersed on the cotton fabric surface. Ag contents in the hybrid fabrics were measured by the techniques of inductively coupled plasma atomic emission spectroscopy and UV-vis, and the antibacterial properties of hybrid fabrics were tested by the shake flask and agar diffusion plate method. It is found that the Ag NP coated cotton fabrics exhibit excellent antimicrobial activities against both the Gram-negative bacterium of Escherichia coli (E. coli) and the Gram-positive bacterium of Staphylococcus aureus ( S. aureus). The percentages of reduction bacteria remain at 91.8% and 98.7% for S. aureus and E. coli, respectively, even after 50 cycles of consecutive laundering, which indicates that the antibiotic performance of the as-fabricated hybrid fabrics is also durable.