Synthesis Of Nano-silver Composite Materials And The Study Their Properties

Nano material is a volume of less than100nm particle materials, relative to the bulk size of materials, the small volume nanoparticles display more novel and more excellent characteristics. As a kind of nano materials, nano silver has a volume effect, surface effect, quantum size effect and the macroscopic quantum tunnel effect, this materials have great developing Prospect and broad Application in super conductivity, photoelectricity, antibacterial, catalytic fields, so we must master the rules of crystal growth in the nano-silver and influence factors in order to find a set of fast, stable and green method to synthetize of nano-silver.(1)In this experiment, we use bovine serum albumin (BSA)、silver nitrate、 sodium borohydride (NaBH4) as raw materials and BSA as template,through liquid phase reduction method of synthesis of BSA coated nano-silver. Experiments discusses the process of nano-silver crystal growth and the effects of different concentration of the BSA, PH, temperature on the BSA coated nano-silver. By adjusting the reaction conditions can control the nano-silver composites size at5~10nm and the best reaction conditions is:2.5g/ml BSA,10-3mol/L AgNO3、30℃、 PH=10.Using the characteristic of nano-silver we test the antibacterial mechanism by killing E.coli, Results show that the nano-silver composite have great value in antibacterial research.(2)Using polyvinylpyrrolidone(PVP)、polyaniline (PAN)、oleic acid (OA)、 cysteine (L-cys) as caping agents, through the liquid phase reduction method to synthesize different caping agents coated nano-silver. In room temperature they through vaporizing and authigenic sediment make film on plastic substrate, via four probe method get the results that Ag/PAN NPs has the lowest rate of resistance and Ag/PVP NPs has the best film feature. Through the transmission electron microscopy (TEM)> X-ray diffraction(XRD) analytical observation, we found that nano-silvers were sphere or round-like shape with dispersible uniformity、stable condition and crystal structure is face-centered cubic crystal structure.(3)We test the antimicrobial properties of nano-silvers composite through the inhibition of the nano-silvers again E. coli. the infrared spectrum analysis and X-ray diffraction and transmission electron microscopy (TEM), fluorescence spectra different means to analyse different caping agents coated nano-silver particles. Through the inhibition zone test、absorbance ratio method and test the K+concentration of E.coli environment, we found Ag/OA NPs has the best antimicrobial effects, but in microcalorimetry by Ag/OA NPs react on Tetrahymena its toxic effect is the strongest one.