Correlation between Electrical Conductivity

CORRELATION BETWEEN ELECTRICAL CONDUCTIVITY and MECHANICAL PROPERTIES [72,73.75,84] 

The correiations observed between the electrical conductivity and the mechanical properties (moduius and tensile strength) are general. In every case studied, the achievement of improved structurai leads to increased eiectrical conductivity and increased mechanical properties. This generality can be understood as a fundamental feature of conjugated polymers. 

Although the electrical conductivity is enhanced by the relativeiy high mobility associated with intra-chain transport, one must have the possibility of inter-chain charge transfer to avoid the iocaiization inherent to onedimensional electronic systems [1]. The eiectricai transport becomes three-dimensional (and thereby truly metallic) only if there is a high probability that an electron will have diffused to a neighboring chain between defects on a single chain. For well-ordered crystalline material in which the chains have precise phase order, the interchain diffusion is a coherent process. In this case, the condition for extended anisotropic transport is that [1,4] 

There is ample evidence, summarized in this review, that conducting polymers can be processed. We conclude that there exists a possibility of two broad categories of heavily doped conducting polymers  

Commodity Materials with Routine Properties Disordered conductors in which the electronic wavefunctions are localized (by the disorder) and in which the transport is via (thermally assisted hopping. To achieve such materials (either with pure polymers or in the form of blends) all that is required is a 

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H. Yoon, B. S. Jung, H. Lee, Correlation between electrical conductivity, thermal-conductivity, and ESR intensity of polyaniline, Synthetic Metals 1991,41,699. 

Barton [1966], Nakajima [1972], and Namikawa [1975] empirical relation, usually designated by BNN, has played a useful role for some time in the analysis of dispersed frequency response data (e.g. Dyre [1988], Macdonald [1996], Dyre and Schrpder [2000], Porto et al. [2000]). It involves a loosely defined parameter, p, expected to be of order 1, and Nakajima and Namikawa believed that it arose from correlation between electrical conduction and dielectric polarization, apparently because it involved both measured dc conductivity and a dielectric strength quantity Ae. 

T. Nakajima [1972] Correlations Between Electrical Conduction and Dielectric Polarization in Inorganic Glasses, in 1971 Annual Report, Conference on Electrical Insulation and Dielectric Phenomena (National Academy of Sciences, Washington, DC), 168-176. 

H. Namikawa [1975] Characterization of the Diffusion Process in Oxide Glasses Based on the Correlation between Electric Conduction and Dielectric Relaxation, J. Non-Cryst. Solids 18, 173-195. 

A recent NMR study indicated a clear correlation between electrical conductivity and the changes in the NMR spectrum that take place as a function of doping [206] (see Section 6.3.4). 

XPS was also used [108] to study the role of a bromine oxidant in the chemical copolymerization with respect to the amount of bromine incorporated and its interaction with the copolymer. The results of this study shows a direct correlation between electrical conductivity and the concentration of positively charged N atoms along the polymer chain. In addition, there is some bromine substitution on the ring. About 20-33% of the total Br is incorporated as covalent bromide and there is evidence to suggest that a higher Br ion content is found in more conducting polymers, which accounts for the more extensive oxidation of the nitrogen atom. 

Chang, S.C. Oxygen chemisorption on tin oxide correlation between electrical conductivity and EPR measurements. J. Vac. Sci. Technol. 1980,17, 366-369. 

There was significantly correlation between electrical conductivity and AC concentration in SAcEW(P<0.01) (Fig.4). 

Flaws in the anodic oxide film are usually the primary source of electronic conduction. These flaws are either stmctural or chemical in nature. The stmctural flaws include thermal crystalline oxide, nitrides, carbides, inclusion of foreign phases, and oxide recrystaUi2ed by an appHed electric field. The roughness of the tantalum surface affects the electronic conduction and should be classified as a stmctural flaw (58) the correlation between electronic conduction and roughness, however, was not observed (59). Chemical impurities arise from metals alloyed with the tantalum, inclusions in the oxide of material from the formation electrolyte, and impurities on the surface of the tantalum substrate that are incorporated in the oxide during formation. 

LAJs incorporating polymer films on top of the organic SAMs showed that these junctions allow for studying the correlation between electrical properties and chemical structure. Both de Boer et al. [80] (Fig. 7) and Rampi et al. [79], by spin-coating respectively PEDOT PSS and PPV on top of alkane SAMs, extracted from the electrical measurement [i = 0.57 A-1 and [j = 0.90 A-1. Rampi et al. also showed that it is possible to measure electrical properties of polyphenyl chains with a [1 0.61 A, and that the PPV polymer layer is much more conductive that... 

The electrical resistivity method of subbottom exploration/surveying is based on the relationship/correlation between the conductivity of soils and rocks and the ion concentration in their pore waters. The resistivity is, therefore, low in saturated clays, moderate in saturated sands/granular soils, and hi in dense rocks with a few voids, little moisture, and small amount of dissolved salts. 

Among many other microstructural parameters, porosity is one such physical parameter, which is generally used to describe the degree of porous nature of a PS layer. Porosity has been well researched with the fabrication methods and environment. Therefore, if this physical parameter could be correlated with electrical conductivity of the PS using any analytical way, it could serve an important role in tailoring the microstructure to obtain desired device properties. However, not much work has been done to explore this correlation. Effective medium approximation (EMA) as proposed by Bruggeman was used to some extent to determine a correlation between the effective conductivity of the PS layer and porosity of the layer ... 

Certain of these polymers have been studied as catalysts for the decomposition of hydrazine (/, 9,10) and the decomposition of hydrogen peroxide 11). The copper-containing polymers are the most active ones, whereas zinc and cadmium polymers were inactive (/, 9). The nature of the ligands attached to the metal atom was found to affect catalytic activity. The catalysis that was observed for the polymers was greater than for similar monomeric chelates or metal oxides. No correlation was observed between electrical conductivity of the chelate and its catalytic activity (9). 

Electrical properties were measured for various membranes after they were used in reverse osmosis desalination to study the possible correlation between electrical properties and membrane performance. Membranes were air-dried upon removal from the reverse osmosis cells and placed in the system used for measuring the electrical properties described above. The results of this study are given in Table IX. The tabulated values for the conductances(G) have been corrected for the 0.599M solution resistances of 16.6, 22.8, and 11.4 ohm cm for NaCl, choline chloride, and MgCl2, respectively. 

Vulcani2ed mbber is an insulator (volume resistivity is 10 Q-cm), and the static generated by mbber tires created serious problems in vehicles until the introduction of electrically conductive carbon black as a reinforcing pigment. An excellent correlation was found between the potential generated and the resistivity of the tires (127,128) (see Rubber natural). 

The Contact between Solvent and Solute Particles Molecules and Molecular Ions in Solution. Incomplete Dissociation into Free Ions. Proton Transfers in Solution. Stokes s Law. The Variation of Electrical Conductivity with Temperature. Correlation between Mobility and Its Temperature Coefficient. Electrical Conductivity in Non-aqueous Solvents. Electrical Conduction by Proton Jumps. Mobility of Ions in D20. 

Similar results were reported by Freidin et al. [568]. Moreover, a correlation was reported [360] between the particle size of tantalum powder obtained by electrolysis of fluoride - chloride melts and its electric conductivity. 

The dependence of the initial velocity of changes in the electrical conductivity of Au/ZnO being acted upon by He on the surface concentration of Au (curve 2) also has its clear maximum at some point of 2 10 atoms/cm. The fact that peaks of curves / and 2 are abscissaspaced apart almost an order of magnitude engages our attention, i.e. we see that there is no direct correlation between the secondary emission currents and the sensitivity of Au/ZnO film to metastable atoms. 

Investigations carried out on specimens of the same semiconductor, prepared by different methods, have shown that there is a correlation between the catalytic activity of a specimen in relation to the hydrogen-deuterium exchange reaction and its initial electrical conductivity. Electron... 

We see that the correlation between the electrical conductivity of a specimen and its catalytic activity established by the electronic theory (1) must show up distinctly and in fact reveals itself in the case of the hydrogen-deuterium exchange reaction. 

It has been reported that the electrical properties of single molecules incorporating redox groups (e.g. viologens [114, 119, 120, 123, 124], oligophenylene ethynylenes [122, 123], porphyrins [111, 126], oligo-anilines and thiophenes [116, 127], metal transition complexes [118,128-132], carotenes [133], ferrocenes [134,135],perylene tetracarboxylic bisimide [93, 136, 137] and redox-active proteins [138-143]), can be switched electrochemically. Such experiments, typically performed by STM on redox-active molecules tethered via Au-S bonds between a gold substrate and a tip under potential control, allow the possibility to examine directly the correlation between redox state and the conductance of individual molecules. 

The central issue which has to be addressed in any comprehensive study of electrode-surface phenomena is the determination of an unambiguous correlation between interfacial composition, interfacial structure, and interfacial reactivity. This principal concern is of course identical to the goal of fundamental studies in heterogeneous catalysis at gas-solid interfaces. However, electrochemical systems are far more complicated since a full treatment of the electrode-solution interface must incorporate not only the compact (inner) layer but also the boundary (outer) layer of the electrical double-layer. The effect of the outer layer on electrode reactions has been neglected in most surface electrochemical studies but in certain situations, such as in conducting polymers and... 

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