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Antibacterial activity and nanocomposite properties of monodispersed silver nanoparticles synthesized by the microwave method
Author(s)
Date Issued
January 1, 2016
Type
Article
Abstract
Monodispersed colloidal silver nanoparticles (Ag-NPs) were synthesized by a simple and rapid microwave method. A precursor, AgNO3, was reduced by ethylene glycol (EG) and N,N-dimethylformamide (DMF) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer or capping agent. It was found that the concentration of AgNO3 significantly affected Ag-NPs particle sizes. The particle sizes decreased when the concentration decreased from 0.1 to 0.05 and 0.01 M, which corresponded to narrow size distribution of the particle diameters of approximately 60 to 80, 30 to 40 and 10 to 20 nm. The spherical-shaped monodispersed Ag-NPs were obtained by using a volume ratio of EG to DMF of 2.75:2.25, microwave power of 400 W and heating time of 2 min. The volume ratio of EG to DMF and the microwave power influenced the uniformity of the Ag-NPs shape and size, while the heating time had no effect. For antibacterial application, 60-80 and 10-20 nm Ag-NPs showed good disinfection ability against Escherichia coli (ATCC 25922) at the minimum inhibitory concentrations (MIC) of 32 and 16 (μg × ml-1, respectively. In addition, the electrical resistance of the nanocomposites of DMF-loaded Ag-NPs (20-50 nm) without PVP on single-walled carbon nanotubes and polyethylene terephthalate (PET) was measured. As a result, it is obvious that the Ag-NPs help to increase the electrical conductivity of the nanocomposites as the electrical resistance of the Ag-NPs nanocomposites was 4.68 kΩ × cm-2 compared to that of the nanocomposites without Ag-NPs of 8.76 kΩ × cm-2.
Citation
Materialpruefung Materials Testing, 58(6), 553-560, 2016