Metallic nanoparticle composites applications

Since nanoscale metal nanoparticles are applicable to a number of areas of technological importance, the nano-structured materials chemistry will occupy much attention of scientists. It is certain that controlling the primary structures of metal nanoparticles, that is, size, shape, crystal structure, composition, and phase-segregation manner is still most important, because these structures dominate the physical and chemical properties of metal nanoparticles. Now the liquid phase synthesis facilitates the precise control of the primary structures. 

Copper nanoparticles have been synthesized in silica by 50 keV Cu ion implantation with doses of 8.0x10 ion/cm. N anoparticles were c haracterized by absorption band of surface plasmon resonance in the visible range. Metal nanoparticle composite glasses were analyzed by the Z-scan method at the IR wavelength of NdiYAG laser radiation 1064 nm. The third order nonlinear susceptibility in the analyzed medium with simultaneous nonlinear refraction and absorption were considered as complex values. It is suggested that the samples with nonlinear absorption is perspective ones for optical applications. 

It is said that the 21st century is the age of nanotechnology since nanoparticles are applicable to an increasing number of areas. Therefore, this research field will occupy the much attention of scientists. Precisely controlling the primary size and structure of metallic nanoparticles, i.e., size, shape, crystal structure, and composition, however, is... 

CNTs-nanoparticles composites have also been exploited for electrochemical sensing applications [17, 118, 119[. Incorporation of metal and oxide nanoparticles has been demonstrated to enhance the electrocatalytical efficiency. A wide range of particles have been used (Pt, Pd, Co, FeCo alloy, Co, Cu, Ag, Cu) and in some cases such CNT/nanoparticles have been combined together with charged polymers [17]. 

Willner and coworkers demonstrated three-dimensional networks of Au, Ag, and mixed composites of Au and Ag nanoparticles assembled on a conductive (indium-doped tin oxide) glass support by stepwise LbL assembly with A,A -bis(2-aminoethyl)-4,4 -bipyridinium as a redox-active cross-linker.8 37 The electrostatic attraction between the amino-bifunctional cross-linker and the citrate-protected metal particles led to the assembly of a multilayered composite nanoparticle network. The surface coverage of the metal nanoparticles and bipyridinium units associated with the Au nanoparticle assembly increased almost linearly upon the formation of the three-dimensional (3D) network. A coulometric analysis indicated an electroactive 3D nanoparticle array, implying that electron transport through the nanoparticles is feasible. A similar multilayered nanoparticle network was later used in a study on a sensor application by using bis-bipyridinium cyclophane as a cross-linker for Au nanoparticles and as a molecular receptor for rr-donor substrates.8... 

All results reviewed herein demonstrate that the microgel particles may serve as nanoreactors for the immobilization of catalytically active nanostructures, namely for metal nanoparticles and enzymes. In both cases, the resulting composites particles are stable against coagulation and can be easily handled. Moreover, the catalytic activity of metal nanoparticles can be modulated through the volume transition that takes place within the thermosensitive microgel carrier system. Similar behavior has been also observed for the temperature dependence of enzymatic activity. Thus, the microgel particles present an active carrier system for applications in catalysis. 

Thin-film metal (metal oxide)/polymer nanocomposites with different inorganic phase contents were obtained by using the cold-wall vacuum co-deposition technique. A range of metals was shown to be applicable to form nanocomposite thin films with PPX, i.e., Al, Ti, Pd, and Sn. AFM studies show the metal nanoparticles to have a size of 7-50 nm. Within the composite the polymer forms more or less spherical globules with a maximum size of about 200 nm. The interfacial regions between neighbouring polymeric spherulites contain nanoparticles of the inorganic filler. 

Ag NPs can be applied for preparation of conductive composites (de Azevedo et al. 2008) and layers (conductive inks) (Zhao et al. 2010). The unique optical and electronic properties of colloidal metal nanoparticles could be a basis for possible applications in optoelectronics (Yua et al. 2004). 

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