Template morphology

Organic template structures derived by self-assembly processes of amphiphiles are imprinted into cross-linked networks, mostly of the inorganic type. The template morphology determines the structure and morphology of the entire pore system. Furthermore, detailed investigation of the pore structure allows inferences to be dl-awn about the template, and therefore, about the self-assembly process. 

It was indicated in the previous section that the promise of nanocasting is that the template morphology will fully determine the structure of the porous system. However. certain conditions have to be fulfilled n the template-network combinations in order to make the nano-casting process work. 

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. 

To control the formation of nanoparticles with desired size, composition, structure, dispersion, and stability, a multifunction nanoagent is used. The active metals (Pd and Pt) react with the functional groups of the nanoagent, i.e., a pol5mier template. The polymer template determines the size, monodisperity, composition, and morphology of the particles (which is somewhat reminiscent of the reversed micelles technique mentioned above). 

C -CP-MAS NMR provides subtle information about the degree of solvation of the polymer chains of a CFP in a given solvent and consequently it may be qualitatively correlated with the nanometer scale morphology of the polymer matrix. In fact, the prerequisite that enables a polymer framework to develop a nanoporosity is the ability of the polymer chains and its pendants to be suitably solvated by the liquid medium [26-28]. Therefore, C -CP-MAS NMR spectra provide the basis for a first level screening of the possibility of a CFP in a given solvent to be employed as an hexo-template, able to accommodate metal nanoclusters chemically produced in its interior (see below and Ref. [29]). 

According to Ref. [12], template for synthesis of nanomaterials is defined as a central structure within which a network forms in such a way that removal of this template creates a filled cavity with morphological or stereochemical features related to those of the template. The template synthesis was applied for preparation of various nanostructures inside different three-dimensional nanoporous structures. Chemically, these materials are presented by polymers, metals, oxides, carbides and other substances. Synthetic methods include electrochemical deposition, electroless deposition, chemical polymerization, sol-gel deposition and chemical vapor deposition. These works were reviewed in Refs. [12,20]. An essential feature of this... 

By changing the ultrasound power, changes in the mesoporosity of ZnO nanoparticles (average pore sizes from 2.5 to 14.3 nm) have been observed. In addition to the changes in mesoporosity, changes in the morphology have also been noted [13]. Recently, Jia et al. [14] have used sonochemistry and prepared hollow ZnO microspheres with diameter 500 nm assembled by nanoparticles using carbon spheres as template. Such specific structure of hollow spheres has applications in nanoelectronics, nanophotonics and nanomedicine. 

Tao C, Zheng S, Mohwald H, Li J (2003) CdS crystal growth of lamellar morphology within templates of poly electrolyte/surf actant complex. Langmuir 19(21) 9039-9042... 

The most exciting challenge is probably the preparation of BN nanostructures, including nanofibers and nanotubules, using the template-assisted PDCs route. Such an approach could allow us to control the morphology and size of the nanostructured BN materials to be incorporated into the BN matrix. This should significantly enhance the mechanical performance of the resulting composites compared to composites reinforced by BN microfibers. 

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