Conductivity nanotubes

Regev O, ElKati PNB, Loos J, Koning CE (2004) Preparation of conductive nanotube-polymer composites using latex technology. Adv Mater 16 248-251. 

If He or Ar is added to the vacuum chamber then metallic (electrical conducting) nanotubes are made in the majority this accounts for up to 91% of the nanotubes produced (Figure 14.8). 

Quantum Molecule r /namirc Heat Conductivity (Nanotube, Superlattice) Calculation of Various Nano- stuructures Thermal Property of Nano-structure. 

A single-electron transistor (SET) has been prepared by Cees Dekker and coworkers (Science, 293, 76, (2001)) with a conducting nanotube. The SET is prepared by putting two bends in a tube with the tip of an AFM. Bending causes two buckles that, at a distance of 20 nm, serves as a conductance barrier. When an appropriate voltage is applied to the gate below the barrier, electrons tunnel one at a time across the barrier. 

Bondavalli, E, Legagneux, E, Pribat, D., Lebarny, P and Naigle, J. (Thales) 2010. Conductive nanotube or nanowires FET transistor network and corresponding device, for detecting analytes. European Patent WO2006128828.2010, October 27. 

Inorganic nanoflllers such as clays or ceramics may improve mechanical properties and dielectric properties. An abundant literature has been devoted to layered silicates for applications in the biomedical domain, hydroxyapatite (HAp e.g., nanoparticles of 300 nm in Figure 13.1a) might be of interest. Ferroelectric ceramics are attractive for their high dielectric permittivity and electroactive properties. As an example, BaTiOa particles with d 700 nm are shown in Figure 13.1b. Conductive nanoparticles should induce electrical conductivity in polymeric matrices, but to preserve the mechanical properties, small amount should be used. Consequently, there is great interest in conductive nanotubes [i.e., carbon nanotubes (CNTs)], which exhibit the highest... 

All these wet-processing methods for nanotube films seem to share some common features, as determined by the properties of SWNTs and their networks in the coated films. It is known in the literature that the resistance at an inter-tube junction is higher when the junction is between nanotube bundles. " Therefore, the homogeneous dispersion and individualization of SWNTs are a prerequisite to the formation of more conductive nanotube films in terms of wet-processing methods. Indeed, dispersion strategies in these... 

All the HBC nanotubes and nanocoils described above are composed of helically rolled-up bilayer tapes and possess a supramolecular helical chirahty as an essential structural element. This is quite interesting, since most HBC molecules examined are devoid of stereogenic centers. Conductive nanotubes... 

Also, electrical properties of CNTs can be affected by crystallographic defects. A common result is dropped conductivity through the defective section of the tube. A defect in conductive nanotubes can cause the adjacent section to become semiconducting, and particular monatomic vacancies induce magnetic properties. 

Figure 3.4 Schematics of ORR electrocatalyst s morphologies. (A) Metal catalyst such as Pt and metal alloy catalyst such as PtPd supported on a conductive material such as carbon or metal oxide (B) core—shell catalyst such as Au Pt supported on conductive material such as carbon or metal oxide (C) metal catalyst such as Pt and metal alloy catalyst such as PtPd supported on a nanofibre such as carbon or metal-oxide nanofibre and (D) core—shell catalyst such as Au Pt supported on conductive nanotubings such as carbon nanotubings. (For color version of this figure, the reader is referred to the online version of this book.)...

Obviously, STFM is a facile and efficient approach to synthesize polymer, in particular PANI, nanostructures because it not only omits hard template and post-treatment of template removal but also simplifies reagents. However, the self-assembly mechanism of the conductive nanotubes of PANI by the STFM is not yet understood. It might be due to the formation of aniline dimer cation radicals which could act as effective surfactants to shape the polyaniline morphology. 

Gui, X., et al. (2010). Soft, Highly Conductive Nanotube Sponges and Composites with Controlled Compressibility, 4,2320-2326. 

With this in mind, a hybrid collector electrode material with CNTs was demonstrated. The highly conductive nanotubes provided sufficient current collection for pseudocapacitive [50] and EDLC devices [47]. In both cases, electrodes made of CNTs deposited on lightweight paper substrates replaced the heavy metal collectors and carbon paste additives and enhanced the specific capacitance of the overall system, compared with results from CNTs deposited on metal substrates. A CNT paper electrode of 30 Wh.kg" and 200 kW.kgr was demonstrated [47]. The downside is that CNTs offer low energy density compared to AC materials and cost more than metal collector substrates. 

Early, in situ radical polymerization was used for the synthesis of poly(methyl methacrylate) (PMMA)-CNT composites [82]. In situ polymerization was performed using the radical initiator 2,2-azobisisobutyronitrile(AIBN). In this reaction, p-bonds in CNTs were initiated by AIBN, and therefore nanotubes could participate in PMMA polymerization to form a strong interface between the CNT and the PMMA matrix. PA6/CNT composites have been prepared by in situ polymerization of e-caprolactam in the presence of pristine and carboxylated CNTs. The e-caprolactam monomer was found to form an electron-transfer complex with CNTs and result in a homogeneous, polymerizable solution. The final composites can be spun into PA6/CNT fibers (Fig. 7) with excellent mechanical and electrical properties [83].This method is also suitable for the fabrication of thermosetting polymer composites with nanofillers. Bauhofer et al. [84] dispersed CNTs in an epoxy solution system based on a bisphenol-A epoxy resin and an amine hardener During nanocomposite curing, electric fields were used to induce the formation of aligned conductive nanotube networks. Recently, the in situ polymerization method... 

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