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Conducting Material (conducting + material)
Selected AbstractsRich Phase Behavior in a Supramolecular Conducting Material Derived from an OrganogelatorADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Josep Puigmartí-Luis Abstract Organic conducting fiber-like materials hold great promise for the development of nanowires that can act as connections in miniature electronic devices, as an alternative to inorganic nanometer scale structures. This article presents a conducting organic tetrathiafulvalene-based supramolecular material which possesses a rich phase behavior with different packing of the molecules in the different forms, evidenced by electron spin resonance (ESR) spectroscopy. The distinct phases of conducting nanofibers can be easily fabricated through the temperature control of their preparation process from a xerogel by doping with iodine vapors. A total of four conducting phases have been identified conclusively using ESR spectroscopy as the key analytical tool. Three of the phases show a good long-term stability and areas in which the I,V curves have ohmic behavior when studied by current sensing (conducting) AFM. They offer promise for applications where electrical nanometer scale connections are required. [source] Evaluation of Thin Film Titanium Nitride Electrodes for Electroanalytical ApplicationsELECTROANALYSIS, Issue 10 2007Carolina Nunes, Kirchner Abstract Titanium nitride is a hard and inert conducting material that has yet not been widely used as electrode material for electroanalytical applications although there are highly developed protocols available to produce well adherent micro and nanostructured electrodes. In this paper the possibilities of using titanium nitride thin films for electroanalytical applications is investigated. Scanning electrochemical microscope (SECM) was used for analysis of the redox kinetics of a selected fast redox couple at thin films of titanium nitride (TiN) in different thicknesses. The investigation was carried out by approaching an amperometric ultramicroelectrode (UME) to the TiN film while the soluble redox couple (ferrocenemethanol/ferrociniummethanol) served as mediator in a SECM configuration. The substrate was biased at a potential so that it rereduces the species being produced at the UME, thus controlling the feedback effect. Normalized current,distance curves were fitted to the theoretical model in order to find the apparent heterogeneous standard rate constant (k°) at the sample. The data are further supported by structural investigation of the TiN films using scanning force microscopy and X-ray photoelectron spectroscopy. It was found that the kinetics are little influenced by prolonged storage in air. The heterogeneous standard rate constants in 2,mM ferrocenemethanol were (0.73±0.05)×10,3,cm s,1 for 20,nm TiN thin layer, (1.5±0.2)×10,3,cm s,1 for 100,nm TiN thin layer and (1.3±0.2)×10,3,cm s,1 for 300,nm TiN thin layer after prolonged storage in air. Oxidative surface treatment (in order to remove organic adsorbates) decreased the kinetics in agreement with a thicker oxide layer on the material. The results suggest that their direct use for amperometric detection of reversible redox systems in particular at miniaturized configurations may be advantageous. [source] A Study of the Determination of Cu(II) by Anodic Stripping Voltammetry on a Novel Nylon/Carbon Fiber ElectrodeELECTROANALYSIS, Issue 7 2004A. Mylonakis Abstract In this work we report a new electrode material formed by injection-moulding of a conducting polymer consisting of carbon fibers in a Nylon matrix. This material is highly conductive, inexpensive, easy to mould in different shapes and requires minimal pretreatment. The electrode was tested as a mercury-free sensor for the trace determination of Cu(II) by anodic stripping voltammetry (ASV). The deposition and stripping behavior of copper on the conducting material was initially studied by cyclic voltammetry and the chemical and instrumental parameters of the determination were investigated. The electrode has been shown to be suitable for the determination of Cu(II) in the range 8,,g L,1 to 30,mg,L,1 (with deposition times ranging from 30,s to 10,min) with a relative standard deviation of 2.2% (at the 0.5,mg,L,1 level) and a limit of detection of 8,,g L,1 Cu(II) for 10,min of accumulation (at a S/N ratio of 5). The electrode was, finally, applied to the determination of copper in tap-water, pharmaceutical tablets and bovine serum with recoveries of 97.4, 94.9 and 93.4%, respectively [source] Nitrobenzene adsorption in activated carbon as observed by NMRAICHE JOURNAL, Issue 1 2003L. Pel The adsorption of nitrobenzene in activated carbon was investigated by nuclear magnetic resonance (NMR). Because of the short relaxation times and carbon is an electrically conducting material, a specially adapted NMR setup was used. It was found that during the adsorption process the nitrobenzene profiles can be scaled using the Boltzmann transformation and the overall effective diffusivity can be approximated by an exponential function of the nitrobenzene content. [source] Synthesis and characterization of epoxidized polybutadiene/polyaniline graft conducting copolymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2004F. R. De Risi Abstract In this article the synthesis and characterization of an elastomeric conducting material, obtained by grafting polyaniline (EB) on commercial cis -1,4-polybutadiene (PB), are described. PB was first partially epoxidized in chloroform solution using meta-chloroperbenzoic acid (MCPBA). The conducting polymer was then grafted to the activated polybutadiene (EPB) via the aminolysis reaction between the polyaniline NH2 terminal groups and the oxirane rings. The material so obtained (EPBPAN) and the epoxidized intermediate product were characterized by 1H NMR, 13C NMR, Fourier transform infrared, and ultraviolet,visible spectroscopy, thermal and mechanical analysis, and electrical conductivity measurements. The effect of the sample deformation on conductivity also was analyzed. The HCl doping of the EPBPAN film induced crosslinking reactions, generated by the acid cleavage of unreacted oxirane groups. The electrical conductivity of the doped material reached values of about 10,5 ,,1 cm,1. The key characteristics of our elastomeric conducting material are its simple synthesis, its starting as a commercial product, and the solubility of its undoped form in a common low-boiling organic solvent like chloroform. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3082,3090, 2004 [source] ChemInform Abstract: Reduction-Tolerant Oxygen-Permeable Perovskite-Type Oxide Sr0.7Ba0.3Fe0.9Mo0.1 O3- ,.CHEMINFORM, Issue 36 2010Xueliang Dong Abstract The title compound, a new mixed ionic-electronic conducting material, is synthesized by a combined EDTA,citrate complexing sol,gel process from Sr, Ba, and Fe nitrates, and MoO3 (calcination in air at 950 °C for 5,10 h, sintering at 1200 °C for 5,10 h). [source] Ion-Conducting Probes for Low Temperature PlasmasCONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-7 2008S. A. Meiss Abstract Probes interacting with a low temperature plasma are typically built of electron conducting materials, mostly metals. We apply yttria-stabilized zirconia (YSZ) which is oxygen ion conducting at elevated temperatures and which is a typical solid electrolyte with high ionic and negligible electronic conductivity. The processes at the plasma|YSZ interface are discussed and first results of measurements with ion-conducting single- and double-probes in oxygen containing radio frequency plasmas are presented. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Magnetic and viscous coupling at the core,mantle boundary: inferences from observations of the Earth's nutationsGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2007B. A. Buffett SUMMARY Dissipative core,mantle coupling is evident in observations of the Earth's nutations, although the source of this coupling is uncertain. Magnetic coupling occurs when conducting materials on either side of the boundary move through a magnetic field. In order to explain the nutation observations with magnetic coupling, we must assume a high (metallic) conductivity on the mantle side of the boundary and a rms radial field of 0.69 mT. Much of this field occurs at short wavelengths, which cannot be observed directly at the surface. High levels of short-wavelength field impose demands on the power needed to regenerate the field through dynamo action in the core. We use a numerical dynamo model from the study of Christensen & Aubert (2006) to assess whether the required short-wavelength field is physically plausible. By scaling the numerical solution to a model with sufficient short-wavelength field, we obtain a total ohmic dissipation of 0.7,1 TW, which is within current uncertainties. Viscous coupling is another possible explanation for the nutation observations, although the effective viscosity required for this is 0.03 m2 s,1 or higher. Such high viscosities are commonly interpreted as an eddy viscosity. However, physical considerations and laboratory experiments limit the eddy viscosity to 10,4 m2 s,1, which suggests that viscous coupling can only explain a few percent of the dissipative torque between the core and the mantle. [source] Proton conducting membranes based on poly(vinyl chloride) graft copolymer electrolytesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2008Jin Kyu Choi Abstract The direct preparation of proton conducting poly(vinyl chloride) (PVC) graft copolymer electrolyte membranes using atom transfer radical polymerization (ATRP) is demonstrated. Here, direct initiation of the secondary chlorines of PVC facilitates grafting of a sulfonated monomer. A series of proton conducting graft copolymer electrolyte membranes, i.e. poly(vinyl chloride)- g -poly(styrene sulfonic acid) (PVC- g -PSSA) were prepared by ATRP using direct initiation of the secondary chlorines of PVC. The successful syntheses of graft copolymers were confirmed by 1H-NMR and FT-IR spectroscopy. The images of transmission electron microscopy (TEM) presented the well-defined microphase-separated structure of the graft copolymer electrolyte membranes. All the properties of ion exchange capacity (IEC), water uptake, and proton conductivity for the membranes continuously increased with increasing PSSA contents. The characterization of the membranes by thermal gravimetric analysis (TGA) also demonstrated their high thermal stability up to 200°C. The membranes were further crosslinked using UV irradiation after converting chlorine atoms to azide groups, as revealed by FT-IR spectroscopy. After crosslinking, water uptake significantly decreased from 207% to 84% and the tensile strength increased from 45.2 to 71.5,MPa with a marginal change of proton conductivity from 0.093 to 0.083,S,cm,1, which indicates that the crosslinked PVC- g -PSSA membranes are promising candidates for proton conducting materials for fuel cell applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||