Dendritic nanocomposites

Very recently, a novel and versatile method has been reported for the construction of stable, zero-valent metal quantum dots, using dendrimers as well-defined nano-template/containers. The concept involves the use of dendrimers as hosts to preorganize small molecules or metal ions, followed by a simple in situ reaction, which immobilizes and incarcerates these nanodomains (Figure 17) [89]. The size, shape, size distribution, and surface functionality of the dendritic nanocomposites are determined and controlled by the architecture. Dendrimer-based nanocomposites display unique physical and chemical properties as a consequence of the atomic/molecular level interactions between the guest and host components within the dendrimer as well as the dendrimer interaction with various solvents and media. 

MEM devices, thin films, (fullerenes, nanotubes, nanofibers, integrated circuits) dendritic polymers, nanoparticles, inorganic-organic nanocomposites nanoelectronic devices)... 

Polymer-Clay Nanocomposites Dendrimers and Other Dendritic Polymers... 

Antimicrobial CS-silver nanocomposites are also potentially new and exciting antimicrobial agents against varions pathogens. CS-silver nanocomposites, either in the form of silver NP or as ionic dendritic strnctures (Ag ) can be easily synthesised by a simple and environmentally friendly in situ chemical reduction process and could be efficient antimicrobial agents. Below specific critical concentrations, the collective action of silver NP and Ag " ions facilitate enhanced and synergistic antibacterial activity. 

Besides clay-based nanocomposites, there has been huge discussion on the metallic and semiconductor-based hybrid materials. The ability of polymer materials to assemble into nanostructures describes the use of polymers providing exquisite order to nanoparticles. Finally, a discussion on potential applications of polymer—nanoparticle composites with a special focus on the use of dendrite polymers and nanoparticles for catalysis should follow (Polymer-Nanoparticle Composites Part 1 (Nanotechnology), 2010) (Figure 1.15). 

Toughened epoxy resins and epoxy nanocomposite systems were synthesized using DGEBA resin, diethylene famine hardener, octadecylammonium modified montmorillonite and epoxy functional dendritic hyperbranched polymer (Boltorn El, Perstorp Spedahty Chemicals, Sweden) with an epoxy equivalent weight of 875 g/eq and a molecular weight of 10500 g/mol. 

The nanocomposite of cross-linked ESO and supramolecular (/ )-12-hydroxystrearic acid (HSA) nanofibre was obtained by photo curing ESO/ HSA (10/1 weight ratio) at 100°C. The study revealed that dendritic clusters of HSA nanofibres are formed in the cross-linked ESO matrix. A thermal transition from the mesophase composed of supramolecular nanofibres to the isotropic state was observed at 67°C (A// = 22.6 Jg HSA), while the of crystalline HSA is 11.1°C (AH = 159 J g HSA).The tensile strength at 20°C of the ESO/HSA was 80% higher than that of photocured ESO without HSA. ... 

Fig 15.12 Schematic of silicon/carbon nanocomposite granule formation through hierarchical bottom-up assembly, (a-c). Annealed carbon-black dendritic particles (a) are coated by silicon nanoparticles (b) and then assembled into rigid spheres with open interconnected internal channels during C deposition (c) (Reprinted with permission from Magasinsld et al. [89]. Copyright 2010)... 

Thus, supermolecular liquid crystals with a cyclotriphosphazene dendritic core and polycatenar mesogenic units (144) were obtained in three steps by the conventional sequence of substitution (i), derivatization (ii and iii) methods from [N3P3CI6] (Scheme 9). Due to the microsegregation of the alkyl chains and the aromatic central cores and the space-filling properties, compounds (144) adopt a discotic conformation assembled in a columnar mesophase and illustrate the possibilities of using cyclotriphosphazenes for the design of columnar assemblies at room temperature, in the mesophase or in a vitrified solid state with interest for applications in material science. Similarly, the new family of solution processable, photoluminescent, monodisperse nanocomposite dendrimers (145) (Tg > 165 °C, > 465 °C)... 

Goodson III T (2001) Optical effects manifested by PAMAM dendiimer metal nanocomposites. In Fr6chet JMJ, Tomalia DA (eds) Dendrimers and other dendritic polymers. Wiley, Chichester, pp 515-541... 

Polyaniline/Silver Nanocomposites He and coworkers [56] employed chronopotentiometry to prepare polyaniline/silver (PANI/Ag) nanocomposite films in water-in-IL and IL-in-water microemnlsions, by simultaneous oxidative polymerization of aniline to PANI and rednction of silver nitrate to Ag nanoparticles. The PANI/ Ag prepared in water-in-IL microemulsion was nanofibrous, and the Ag nanocrystals with 5 nm diameter were dispersed homogeneously, whereas the PANI/Ag prepared in IL-in-water microemulsion exhibited dendritic structure, and the diameter of Ag nanocrystals was 50-100 nm. The special structures of the PANI/Ag nanocomposite resulted in more excellent electrochemical activity than that of the pure PANI. 

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