Oxide nanoparticles, inorganic

Figure 4. Schematic representation of the growth model of the inorganic fullerene-like of MoS2 (a) WS2 (b) nested polyhedra from oxide nanoparticles (31a).

Newer immunodetection applications, and particularly the so-called microarrays, employ new fluorescent probes such as europium chelates (Scorilas et al., 2000), lanthanide oxide nanoparticles (Dosev et al., 2005 Nichkova et al., 2006), fluoro-phore loaded latex beads (Orth et al., 2003), dye-doped silica nanoparticles (Zhou and Zhou, 2004 Yao et al., 2006), and inorganic nanocrystals (Gerion et al., 2003 Geho et al., 2005). 

The aerogel-prepared metal oxide nanoparticles constitute a new class of porous inorganic materials because of their unique morphological features such as crystal shape, pore structure, high pore volume, and surface areas. Also, it is possible to load catalytic metals such as Fe or Cu at very high dispersions on these oxide supports and hence the nanocrystalline oxide materials can also function as unusual catalyst supports. Furthermore, these oxides can be tailored for desired Lewis base/Lewis acid strengths by incorporation of thin layers of other oxide materials or by preparation of mixed metal oxides. 

Some non-oxide nanoparticles such as PbS and CdS can be used to prepare polymer-inorganic nanocomposites by a double-microemulsion process [103]. In this case, two precursor micro emulsions must be prepared separately first and then mixed together for polymerization. Using CdS-polymer nanocom-... 

Composite materials can be formed by numerous methods. Two modes in which incorporation of the inorganic material in the template can be achieved will be discussed sol-gel processes or nanoparticle infiltration. They are both solution methods that can be processed at low temperatures, hence allowing the use of polymeric templates. In the first method the sol-gel chemistry is performed after the incorporation of a metal oxide precursor in the polymer matrix or around the template entities. The second method makes use of preformed metal oxide nanoparticles, which are infiltrated into the organic scaffold or suspended in solution with the individual structures for controlled adhesion. 

Preformed metal oxide nanoparticles have been successfully coated on polymer spheres by the use of the layer-by-layer method. This involves the coating of the template spheres with polyelectrolyte layers, which are oppositely charged to the metal oxide nanoparticles to be deposited. Alternating the polyelectrolyte and nanoparticle deposition has led to the successful formation of silica [67,68] and titania [69] coated PS spheres. Using this approach preformed crystalline nanoparticles can be deposited on the organic spheres and crystalline hollow spheres can be obtained without the need of calcination. On removal of the template and the polymer interlayers by heating, hollow spheres of the inorganic material can be obtained [68-70]. This procedure is described in detail in the chapter by Dr Frank Caruso. 

Sol-gel and precipitation methods are simple and commonly used wet-chemical synthesis methods of ceramic nanoparticles such as calcium phosphates, iron oxides, silica, titanium oxides, and zinc oxides. Basically, the sol-gel method uses inorganic precursors (i.e., meal salts or organometalhc molecules) that react in aqueous environment and subsequently form integrated network (gel). For example, metal oxide nanoparticles are often synthesized via the hydrolysis and condensation reactions of metal alkoxides ... 

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