Preparation And Property Research Of Silver/Polyaniline Nanocomposites

As a common noble metal nanomaterials, nano-silver possesses many excellent properties, for example conductivity, catalytic, optical absorption and antibacterial. These special properties of nano-silver depend on its structure, morphology and size. Thus, studying the preparation of different morphology and size silver nanoparticles is significant. As a typical conductive polymer, polyaniline has many advantages, for example simple synthesis process, low cost, high conductivity, chemical stability and reversible electrochemical activity. Silver/polyaniline core-shell complex nanoparticles simultaneously possesses the excellent properties of two materials. It can be used to fabricate catalysts and antibacterial materials.In this paper, we mainly study the preparation of different morphology, size silver nanoparticles. The conductive polymer coated on the surface of silver nanoparticles, in order to prepare silver/polyaniline core-shell complex nanoparticles. TEM, SEM, XRD, UV-VIS and FT-IR are used to character the morphology, composition, size, and structure of resulting products. We investigate the effects of reaction process on the morphology, size, and explore the catalytic properties of the silver/polyaniline core-shell complex nanoparticles. The main contents are as follows:Silver nanoparticles with excellent dispersibility were prepared by reduction of silver nitrate, polyethylene glycol(PEG) as dispersant, ethanol as reductant and the reaction medium. The size of particle distributes in3～5nm. As dispersant, PEG prevents the agglomeration of silver nanoparticles in the reaction process. The effects of different reaction conditions on the size of silver nanoparticles was studied. Increasing the concentration of polyethylene glycol or silver nitrate, the concentration of silver nanoparticles become larger, and the size of silver nanoparticles become smaller. Increasing the reaction time, the size of silver nanoparticles increases. The optimum reaction temperature is30℃.At room temperature, trianglar silver nanoplates and silver nanoparticles were fabricated by aniline and ethanol as reductant, Polyvinylpyrrolidone (PVP) as dispersant, without heating, stirring and other auxiliary conditions. The edge length of the nanoplates are around400～500nm, while the size of silver nanoparticles is80～90nm Only aniline and ethanol simultaneously as reductant, trianglar silver nanoplates can be prepared successfully. Increasing the concentration of aniline or silver nitrate, the edge length of the nanoplates become larger. Increasing the concentration of PVP can improve the dispersibility of trianglar silver nanoplates and silver nanoparticles.Silver/polyaniline core-shell complex nanoparticles were fabricated by hydrothermal route, while aniline as reductant, silver nitrate as oxidant, SDBS as surfactant. The size of composite particles distributes in70～80nm, when the size of silver nanoparticles distributes in40～50nm. Increasing the concentration of the aniline, the thickness of the polyaniline become larger. Increasing the concentration of silver nitrate, the size of silver nanoparticles increases. Increasing the concentration of SDBS, the size of silver nanoparticles decreases. With increasing the reaction time, the polyaniline coating layer tends to complete, the thickness of polyaniline increases.Silver/polyaniline nanocomposites has excellent catalytic capability for nitrobenzene. Polyaniline has the enrichment of nitrobenzene. Nitrobenzene gathers in the surface of silver nanoparticles. The thicker polyaniline is, the faster instant catalytic rate is.