Silver nanoparticles heated

The production of fatty acid-capped silver nanoparticles by a heating method has been reported [115]. Heating of the silver salts of fatty acids (tetradecanoic, stearic, and oleic) under a nitrogen atmosphere at 250°C resulted in the formation of 5-20-nm-diameter silver particles. Monolayers of the capped particles were spread from toluene and transferred onto TEM grids. An ordered two-dimensional array of particles was observed. The oleic acid-capped particle arrays had some void regions not present for the other two fatty acids. 

Stearate-stabilized silver nanoparticles, C17AgNP, were prepared by the simple one-pot thermolysis of silver stearate, C17COOAg. The powder of C17COOAg (1.0 mmol) was placed in the bottom of three necked flask, and then heated up to 250 °C to afford a liquid. Heating the liquid... 

Based on XRD studies we can say that the optical absorption of the films heated at 350-500°C is due to silver germanate, while the features in the films heated at 800°C belongs to silver nanoparticles (Fig. 1). 

Our study h as demonstrated that formation of silver nanoparticles in "Ag -Ge02" system proceeds through the decomposition of silver germanate formed after the earlier steps of film heating. That mechanism provides a considerable stability of Ag nanoparticles to oxidation on heating up to 900°C, suggesting that the silver particles are encapsulated by the matrix. 

PEG is flexible, and water-soluble neutral polymer can serve as a dispersant because of its ability to bind water. In this work bare or coated with PEG (Mw - 8000, 5 mg/ml) silver nanoparticles were heated at 90°C for 20 min. Heating of bare silver nanoparticles resulted in silver coagulation and formation of the large aggregates (Fig. 3a) while heating of PEG modified silver nanoparticles lead to the destruction of silver aggregates and effective stabilization of single nanoparticles (Fig. 3b). 

According to Nath et al. °° for the synthesis of silver nanoparticles on a resin surface, first Ag(I) was taken as the silver amine complex and then the complex was immobilized on the charged cation exchange resins. After that, the resin beads were heated for the formation of Ag20 on the resin surfaee and then treated with sodium borohydride solution for the reduction process (Scheme 2.2). 

Silver nanoparticles were generated using a common technique known as thermal evaporation. The synthesis of aerosol particles of metal via thermal evaporation is shown schematically in Figure 6.13, in which a source of silver is placed into the hot zone of a furnace, heated to create vapor of the sohd silver material, and cooling to nucleate and grow aerosol nanoparticles. 

Nucleated by gold and/or silver nanoparticles, themselves photonucleated with the aid of UV-absorbing cerium (3 ) ions Crystallized (at about 600°C) to dendritic form of lithium metasilicate (LijSiOj), which is soluble in HF add Photonucleation plus heat treatment at higher temperatures (850°C) produces stable hthium disihcate (Li2Si205) and a-quartz... 

Figure 8.7 FE-SEM images of the silver nanoparticles synthesized using formaldehyde as a reductant [a] With 5 min of microwave irradiation at a power of 100 W and [b] with 1 h of conventional heating at 40°C. Reprinted with permission from Ref [64], Copyright [2008], American Institute of Physics.

In a novel method, methacrylate monomers containing well-dispased silver nanoparticles wae in situ synthesized under microwave irradiation. The particles wae spherical in shape with a narrow size distribution ranging from 1.0 to 5.5 nm and with a mean diameter of 2.8 nm. In contrast to conventional heating, the synthesis of Ag nanopartides proceeded uniformly throughout the reaction vessel only unda microwave irradiation, reaching completion of the reaction simultaneously in the whole reaction solution. Successive polymerization of the monomer containing the resulting nanopartides successfully produced Ag nanopartides dispased in the polymer matrix. 

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