Nanoparticle-dispersed materials

Noble metal nanoparticles dispersed in insulating matrices have attracted the interest of many researchers fromboth applied and theoretical points of view [34]. The incorporation of metallic nanoparticles into easily processable polymer matrices offers a pathway for better exploitation of their characteristic optical, electronic and catalytic properties. On the other hand, the host polymers can influence the growth and spatial arrangement of the nanoparticles during the in situ synthesis, which makes them convenient templates for the preparation of nanoparticles of different morphologies. Furthermore, by selecting the polymer with certain favorable properties such as biocompatibiHty [35], conductivity [36] or photoluminescence [37], it is possible to obtain the nanocomposite materials for various technological purposes. 

The preparation and study of metal nanoparticles constitutes an important area of current research. Such materials display fascinating chemical and physical properties due to their size [62, 63]. In order to prevent aggregation, metal nanoparticles are often synthesized in the presence of ligands, functionalized polymers and surfactants. In this regard, much effort has focused on the properties of nanoparticles dispersed into LCs. In contrast, the number of nanoparticles reported that display liquid crystal behavior themselves is low. Most of them are based on alkanethiolate stabilized gold nanoparticles. 

Up to now, a variety of non-zeolite/polymer mixed-matrix membranes have been developed comprising either nonporous or porous non-zeolitic materials as the dispersed phase in the continuous polymer phase. For example, non-porous and porous silica nanoparticles, alumina, activated carbon, poly(ethylene glycol) impregnated activated carbon, carbon molecular sieves, Ti02 nanoparticles, layered materials, metal-organic frameworks and mesoporous molecular sieves have been studied as the dispersed non-zeolitic materials in the mixed-matrix membranes in the literature [23-35]. This chapter does not focus on these non-zeoUte/polymer mixed-matrix membranes. Instead we describe recent progress in molecular sieve/ polymer mixed-matrix membranes, as much of the research conducted to date on mixed-matrix membranes has focused on the combination of a dispersed zeolite phase with an easily processed continuous polymer matrix. The molecular sieve/ polymer mixed-matrix membranes covered in this chapter include zeolite/polymer and non-zeolitic molecular sieve/polymer mixed-matrix membranes, such as alu-minophosphate molecular sieve (AlPO)/polymer and silicoaluminophosphate molecular sieve (SAPO)/polymer mixed-matrix membranes. 

A large fraction of practical catalysts consists of transition-metal or metal oxide nanoparticles dispersed onto the surface of insulator or semiconductor oxides that function as support materials. For industrial applications, the supports employed are selected on the basis of their surface area (high surface area is usually, but not always, desirable), high thermal and hydrothermal stability, chemical stability, and mechanical strength. 

As in any other system, the phase state of the structural elements of nanoparticle dispersions may change induced by variation of physical parameters. This aspect becomes most interesting if the matrix material is affected, e.g., the bulk stmcture of a nanosphere or the wall material of a nanocapsule membrane. This case has very promising practical applications a nanocapsule or a nanoparticle may be loaded while being in one phase state and subsequently sealed by a phase transition. This possibly allows one to produce prefabricated particle dispersions where the hnal encapsulation step is accomplished by addition of the active ingredient at any given point in time. 

Depending on the method of their preparation, the individual nanodiamond particles do not exist as isolated crystallites, but they form tightly bound agglomerates. Apart from unordered sp - and sp -hybridized carbon, they may also include other impurities. The latter may originate either from synthesis or purification, for example, finely dispersed material from the reactor walls may contaminate the sample (Section 5.3). This is especially true for material produced by the detonation or shock wave method, whereas hydrogen-terminated diamond nanoparticles do not show this effect. 

Yoshida et al. reported oxygen evolution by a soft material containing RUO2 nanoparticles dispersed by sodium dodecyl sulfate and embedded into a polymer of poly(N-isopropylacrylamide), cross-linked and sensitized with [Ru(bpy)3] derivatives, in the presence of [Co(NH3)5Cl] " " as the sacrificial oxidant [37]. 

To create nanocomposites materials with specific applications the nanoparticles dispersion control into the polymer matrices still remains a critical challenge for researchers. So, the development of nanocomposite materials requires control over nanoparticle distribution in the polymer matrix. Making connections between nanoparticle dispersion, enhanced the macroscale properties and evaluated the end of life of this materials is then a crucial aspects that is only now beginning to be considered by researchers around the world. So, make these connections is essential to better development and application of the nanotechnology in the near future. 

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