Synthesis, Characterization And Antibacterial Properties Of Silver Nanoparticles And Their Composites

Metal nanomaterials are always one of the important research points ofresearchers in potential applications of photonics, catalysis, sensors, biotechnologyand other fields. Among them, silver nanoparticles as a new functional material, havereceived considerable attention due to their unique physical and chemical properties,and have wide applications in nanoscaled optoelectronic devices, biomarkers,surface-enhanced Raman scattering(SERS) and biomedical composites. Graphene, arising star of carbon material with a neat two-dimensional structure and excellentadsorption capacity, is a ideal base loaded silver nanoparticles, and has been appliedin transparent conductive films, catalysis, detection of gas molecular, particularlysuitable for bio-antibacterial materials.In this paper, nano-silver with different morphologies and graphene/Agnano-composites were obtained with some simple, rapid methods, and themorphologies and structures of products were characterized. The major contents canbe summarized as follows:(1)Sodium citrate as a protective agent, sodium borohydride and ascorbic acid asreducing agent, CTAB as template, silver nanocrystals and silver nanorods wereprepared in an aqueous phase by chemical reduction. By charging the reductantconcentration, reaction temperature and amount of seed, the growth mechanism ofnano-silver were mainly investigated and the factors affecting the morphologies andsizes were analysed. It could provide the basis for synthesizing silver nanocomposites.(2)The Ag/rGO nanocomposites was prepared with liquid phase reductionmethod, using silver nitrate as precursor, graphene oxide as substrate and sodiumcitrate as a environmentally friendly reductant. Graphene oxide was prepared frompristine graphite according to Hummers’ method. The morphologies and structures ofAg/rGO nanocomposites were confirmed by XRD, UV-Vis, TEM, etc. The antibacterial properties were investigated using Escherichia coli, Staphylococcusaureus and Vibrio anguillarum.(3)Firstly, the surfaces of graphene oxide were coated with Poly(dopamine)(PDA) layer by the spontaneous oxidative polymerization of dopamine to form thePDA/GO composites. The weak reducibility of PDA was used to reduce theseabsorbed Ag ions,which were from the precursor AgNO3, into siver nanoparticlesimmobilized on the PDA/GO surfaces. XRD, TEM, and UV-VIS were used tocharacterize the properties of the material, and the antibacterial activity was alsoanalyzed. The results indicated that this nanocomposite possessed good antibacterialproperties and high stability, and exhibited great potential in field of marineantifouling.