Composite metal-polymer nanofiber

The polymer resulting from oxidation of 3,5-dimethyl aniline with palladium was also studied by transmission electron microscopy (Mallick et al. 2005). As it turned out, the polymer was formed in nanofibers. During oxidative polymerization, palladium ions were reduced and formed palladium metal. The generated metal was uniformly dispersed between the polymer nanofibers as nanoparticles of 2 mm size. So, Mallick et al. (2005) achieved a polymer- metal intimate composite material. This work should be juxtaposed to an observation by Newman and Blanchard (2006) that reaction between 4-aminophenol and hydrogen tetrachloroaurate leads to polyaniline (bearing hydroxyl groups) and metallic gold as nanoparticles. Such metal nanoparticles can well be of importance in the field of sensors, catalysis, and electronics with improved performance. 

K. MaUick, M.J. Witcomb, A. Dinsmore, and M.S. Scurrell, Fabrication of a metal nanoparticles and polymer nanofibers composite material by in situ chemical synthetic route, Langmuir, 21, 7964-7967 (2005). 

A gas-solid reaction was further introduced to the electrospiiming technique to incorporate semiconductor nanostructures into polymer nanofibers with better dispersion. The production of well-dispersed PbS nanoparticles in polymer fiber matrices has been achieved by this method (Lu et al., 2005). First, metal salt and polymer were codissolved into one solvent to make a homogeneous solution. Then the above solution was electrospun to obtain polymer/metal salt composite nanofibers. The composite nanofibers were finally exposed to HaS gas at room temperature to synthesize PbS nanoparticles in situ in polymer nanofibers. 

Recent developments in polymer nanotechnology include the exfoliated clay nanocomposites, CNTs, carbon nanofibers, exfoliated graphite, nanocrystalline metals, and a host of other filler modified composite materials. Polymer matrix-based nanocomposites with exfoliated clay are discussed in this section. Performance... 

ElectrochemicaUy active materials such as activated carbons, carbon aerogels, and carbon foams (aU derived from polymers) oxides, hydrous oxides, carbides, and nitrides are used to form composites with carbon nanofibers. Additional active materials such as oxides, hydrous oxides, and carbides can be combined to form a composite. Process requires dispersion in water with carbon nanofiber and subsequent filtralion and washing. Capacitance of 249 F /g was measured from a RuOj xHjO metal oxide and carbon nanofiber composite. 

The electrical and mechanical stability of metal oxide nanofibers fabricated on electrode substrates is one of the most important issues [42]. In order to obtain superior mechanical strength between Ti02 fiber mats and a substrate, a thermocompression step was introduced prior to the calcination step in the creation of inorganic precursor/polymer composite nanofibers. For example, as-spun Ti02 precursor/PVAc composite fibers were hot pressed at 120 °C for 10 min. 

The surfece morphology of a hemitube structure can be controlled by an additional surface treatment process [6,84,93,94]. Choi et al. recently synthesized bumpy metal oxide hemitubes using oxygen plasma-treated polymer nanofibers as a sacrificial template, followed by WO3 sputtering and a subsequent calcination step [94]. The templating nano fibers were prepared using composite nanofibers consisting of 0.5 g of PVP M = 1300 000 g moC ) and 0.5 g of PMMA... 

The following two sections discuss the effects of different solution properties and operational conditions on the stracture (especially, the diameter) of electros-pun polymer nanofibers. Many carbon, ceramic, metal and composite nanofibers are prepared from solutions that contain polymers, and hence the fundamental knowledge covered in the following sections also gives insight to the stractwe control of these nanofibers. 

It is reasonable that, in the synthesis of polymer nanocomposites, the y-ray irradiation method is convenient for growing nanofibers and nanowires of metal chalcogenides due to the shape-control of the macromolecules formed in situ. Figure 7.38 shows some of the resulting nanofiber-dispersed polymer composites,... 

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