Cotton decorated with Cu2O-Ag and Cu2O-Ag-AgBr NPs via an in-situ sacrificial template approach and their antibacterial efficiency.

Cotton fabrics decorated with Cu2O-Ag and Cu2O-Ag-AgBr NPs have been prepared using chemically immobilized Cu2O NPs as sacrificial templates. The objective is to prepare Cu2O-Ag heterostructures with Ag being intimately in contact with Cu2O NPs by galvanic replacement reactions without addition of any external reducing agent. Field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis were used to study the morphology and the chemical composition of the nanocomposites formed on the fabrics. The morphology of the ensuing nanostructures was shown to be dependent on the Ag precursor, AgNO3, concentration. The antimicrobial activity of the treated fabrics was evaluated against Staphylococcus aureus and Escherichia coli as model strains of gram-negative and gram-positive, respectively. The results showed that the fabrics loaded with Cu2O-Ag and Cu2O-Ag-AgBr nanocomposites exhibited enhanced sterilization activity compared to the Cu2O treated fabric.

Hybrid nanocellulose decorated with silver nanoparticles as reinforcing filler with antibacterial properties.

Cellulose (Cel) nanofibrils (CNFs) produced by periodate oxidation of native cellulose fibers were functionalized with silver (Ag) nanoparticles (NPs) using Tollens' reaction. The morphology and chemical composition of the resulting Cel-Aghybrid nanofibrils were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), as well as Fourier-transform infrared (FTIR) and UV-Vis spectroscopies. To check whether the hybridization with Ag affected the reinforcing potential of the CNFs, nanocomposite films based on an acrylic matrix filled with the as-prepared Cel-Ag nanofibrils at different contents were processed by film casting. Their mechanical properties were investigated by dynamic thermomechanical analysis (DMTA). The hybrid Cel-Ag nanofibrils exhibited good bactericidal properties against Gram+ and Gram- bacteria. Interestingly, the presence of Ag NPs did not seem to affect the reinforcing potential of the nanocellulose, and the amount of Ag leached out from films was below the permissible limit of 12 ppb. Nanocomposites based on this hybrid Cel-Ag nanofiller thus have a great potential in the field of active packaging films, coating and adhesives with enhanced antibacterial activity.