Cotton fabric coated with graphene-based silver nanoparticles: synthesis, modification, and antibacterial activity

In this study, silver immobilizing onto graphene oxide (Ag/GO) was synthesized by the in-situ method. Subsequently, silver immobilizing reduced graphene oxide cotton fabric (Ag/rGO/cotton) was made by the dip-coating method in Ag/GO suspension followed by the chemical reduction with the presence of vitamin C as an environmentally friendly reducing agent. The characteristics of Ag/GO, Ag/GO/cotton, and Ag/rGO/cotton were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The results showed that AgNPs were uniformly distributed on the surface of GO sheets with an average size of 10–15 nm. Regarding Ag/rGO/cotton, the fiber surface was evenly covered by Ag/rGO materials. Besides, there was no significant difference between the two samples of Ag/GO/cotton and Ag/rGO/cotton, indicating the reduction reaction possessed no effect on the cotton structure. Moreover, the Ag/rGO/cotton also exhibited effective hydrophobicity with a wetting angle of 103.85 ± 0.75 o. The antibacterial performance of Ag/GO, Ag/GO/cotton, and Ag/rGO/cotton against the Gram-positive (Staphylococcus aureus-S. aureus) and Gram-negative (Pseudomonas aeruginosa-P. aeruginosa) bacteria were determined via the diameter zone of inhibition. The results indicated that the appropriate reducing agent is L-ascorbic acid-vitamin C (VC) with the conditions: the VC:Ag/GO mass ratio of 1:1, the reducing temperature of 140 oC, and the reducing time of 120 min showed the highest antibacterial effect against two types of bacteria. All results of the study confirmed that Ag/rGO/cotton possesses significant potential for several antibacterial applications such as protective equipment.