Preparation And Characterization Of Silver Nanoparticles And Their Antibacterial Properties

Silver-based materials were prepared and applied in catalytic, optical and antibacterial materials in this study. Preparing size controllable silver nanoparticles (AgNPs) has drawn more and more interest due to the size and morphology of silver nanoparticles play an important role on the performance of AgNPs. In this study, different reducing agents and protective agents were used to prepare silver nanopartiles by using chemical reduction methed. The morphologies of silver NPs were characterized by XRD, FTIR, UV, and TEM. The antibacterial properties of the samples were studied.In the presence of poly(amide acid)(PAA) as stabilizer and N,N-dimethylformamide as solvent, the silver nitrate was reduced to obtain monodispersed AgNPs. The FT-IR result indicates that the AgNPs had light influence on the structure of PAA molecule. The XRD result shows the crystalline structure of AgNPs dispersed in PAA. The surface plasmon band transition was monitored with reaction mixture time for three sets of experiment by UV-vis spectroscopy. TEM studies the morphologies of the silver nanoparticles prepared by different PAA concentration and reaction time. The analysis showed that the formation of silver nanoparticles had no obvious effect on the structure of PAA molecular. UV-visible absorption spectra show a significant asymmetry of bimodal. The growth process of AgNPs follows Ostwald ripening law. AgNPs, prepared by the soft and convenient method in mild reaction conditions without stirring and using surfactant, will be beneficial to further study the polyimide-coated silver nanoparticles and prepare silver-doped nanocomposites.AgNPs with good monodispersity and well-dispersion were produced by a convenient method for the reduction of silver nitrate with N,N’-dimethylacetamide in the presence of PVP as the surfactant modification agent. The crystalline of silver was in the composite power of Ag/P VP. The shape and size of the AgNP by reaction time is taken as a variable. The surface plasmon band transition was monitored with reaction mixture time at different reaction temperatures by UV-vis spectroscopy. The crystallinity of AgNPs increased with the reaction time. The formation of Ag+and nanoparticles was influenced by the PVP molecule structure. AgNPs modified by the as-synthesized PVP had a face-centered cubic crystalline structure, in which AgNPs could develop a spherical morphology and their size distribution was very narrow. The preparation provided a new reducing agent to form the AgNPs with more simple operation and shorter time, which facilitates to apply in industrial production.To further explore the antimicrobial properties of AgNPs, the well monodispersed AgNPs were synthesized through reducing silver nitrite by N, N-dimethylacetamide (DMAc) solvent with high-molecular-weight PVP at mild temperature. The obtained AgNPs had a face-centered cubic crystalline structure and significant stability in solvent. The antimicrobial properties of AgNPs were tested by disk diffusion method. The results illustrated that AgNPs have a remarkable antibacterial effect on Staphylococcus aureus. The facility, environment friend and mild reaction conditions of preparing AgNPs make them have great promise for antimicrobial applications.