Nanoscale silver particles

Polymer-protected, monodisperse, nanoscale silver particles (Fig. 9.2.1c and d) have been obtained through spontaneous nucleation by the polyol process as follows (23). PVP (1-25 g) and AgNOj (50-3200 mg) were dissolved in EG (75 mL) at room temperature. Then the solution was heated up to 120°C at a constant... 

The development of the particle size during the synthesis of PVP-protected nanoscale silver particles carried out under the conditions described earlier has been followed... 

As science has advanced, the emergence of nanotechnology has provided new ways of producing silver in its pure form as silver nanoparticles, the sizes of which-as the name suggests-are measured in nanometers. Upon reaching nanoscale, silver particles-like other nanomaterials and primarily by virtue of their extremely small size-exhibit remarkably unusual physico-chemical properties and biological activities, and in recent years major research efforts in this area... 

The formation of semiconductor nanoparticles and related stmctures exhibiting quantum confinement within LB films has been pmsued vigorously. In 1986, the use of the metal ions in LB films as reactants for the synthesis of nanoscale phases of materials was described [167]. Silver particles, 1-2 mn in size, were produced by the treatment of silver be-henate LB films with hydrazine vapor. The reaction of LB films of metal salts (Cd, Ag, Cu, Zn, Ni, and Pb ) of behenic acid with H2S was mentioned. The use of HCl, HBr, or HI was noted as a route to metal halide particles. In 1988, nanoparticles of CdS in the Q-state size range (below 5 mn) were prepared inside LB films of cadmium arachi-... 

Figure 12.10. Micrographs of devices fabricated using gravure printing technology. Left—shows the interdigitated transistor gate fabricated by an ink composed of nanoscale metallic particles. Right—Channel fabricated when using a silver-filled adhesive to print the transistor source and drain.

Conventional studies of inhalation toxicity generally use toxic doses measured in terms of mass per unit volume. Some studies have shown that this unit of measurement may not be appropriate for nanoparticles. For example, in one study of 100 nm particles of titanium dioxide evoked the same amount of pulmonary inflammation as a ten-times greater mass of larger (1-2.5 pm) particles [9]. The smaller-sized greater surface area versions of substances may afford exceptional benefits. For example, silver has been used successfully as a bactericide, but now it has been found that nanoscale silver has greatly enhanced effectiveness [10]. 

Chiolerio A, Virga A, Pandolfi P et al (2012) Direct patterning of silver particles on porous silicon by inkjet printing of a silver salt via in-situ reduction. Nanoscale Res Lett 7 1-7 Fang C, Foca E, Xu S et al (2007) Deep silicon macropores filled with copper by electrodeposition. J Electrochem Soc 154 D45-D49... 

Johnston and coworkers reported the preparation of nanoscale CdS particles in a PFPE-based microemulsion in supercritical CO2 for evaluating the effects of the water/surfactant ratio (ITo) of the microemulsion on the nanoparticle properties (249). They found that the particle size increased significantly with an increase in the Wo value, from which a correlation between average nanocrystal radius and water-core radius was established (Figure 26). Recently, Johnston and coworkers also prepared silver nanocrystals coated with fluorinated ligands (240). These coated nanocrystals could be dispersed in CO2 at moderate pressure and temperature. 

Nanoscale Metallics. Many of the metallization materials previously discussed, such as gold, can be developed into fine particles through either chemical reduction from a metal salt or from vaporization of the bulk metal.89 In fact, metals, such as gold, silver, palladium, and iron, can be harvested in elemental form from vegetation and grains that have been planted... 

In in-situ polymerization, nanoscale particles are dispersed in the monomer or monomer solution, and the resulting mixture is polymerized by standard polymerization methods. This method provides the opportunity to graft the polymer onto the particle surface. Many different types of nanocomposites have been processed by in-situ polymerization. Some examples for in-situ polymerization are polypyrrole nanoparticle/amphiphilic elastomer composites magnetite coated multi-walled carbon nanotube/polypyrrole nanocomposites and polypyrrole/ silver nanocomposites. The key to in-situ polymerization is appropriate dispersion of the filler in the monomer. This often requires modification of the particle surface because, although dispersion is easier in a liquid than in a viscous melt, the settling process is also more rapid. 

The deciding hint for explaining the basic electron transport mechanism in conductive polymers came from studies with nanoparticles of conventional metals like indium, silver, or copper. Nimtz et al. [4] found in 1989 that metallic particles, if prepared on a nanoscale of below 1 p,m down to 10 nm, show some distinct deviations from macroscopic metals (see Figure 1.2). 

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