Polymers electron conduction

Conducting Polymers Electronically conducting polymers (such as polypyrrole, polythiophene, and polyaniline) have attracted considerable attention due to their ability to switch reversibly between the positively charged conductive state and a neutral, essentially insulating, form and to incorporate and expel anionic species (from and to the surrounding solution), upon oxidation or reduction ... 

For a fast catalytic reaction, free access of gas, electrons, protons and water is needed. This leads to a best compromise of the volume fractions of protonconducting polymer, electron-conducting carbon, active sites and void space. 

New Engineering Thermoplastics New High Performance Thermosets Thermotropic Liquid Crystals Lyotropic Liquid Crystals Molecular Composites Advanced Composites Non-Linear Optical Polymers Electronically Conducting Polymers... 

Among the species that dope PPy and PTh and render the polymers electronically conducting are BFJ, CIOJ, CP, CF3SO3, CH3C6H4SO5, PF, and AsF Oi7,n8,i29)... 

Among the electroactive polymers, electronically conducting polymers such as polypyrrole and polythiophene and piezoelectric polymers such as polyvinylidine fluoride (PVDF) are the most promising with regard to tissue engineering applications. 

Secondary electrochromic polymer Electronically conductive traneparent film Glass or plastic substrate... 

Subsequent generations of electrocatalytically active systems use deposited three-dimensional chemical microstructures, these are the polymer modified electrodes. These multilayer polymeric structures contain redox-active groups. Typical examples of the latter include redox polymers, electronically conducting polymers, and ionomer films loaded with redox-active species or loaded ionomers. Much emphasis is placed on these second-generation systems their operational characteristics under steady-state conditions are elucidated mainly by Andrieux and Saveant and Albery and Hillman. The fundamental characteristic of these second-generation polymer-based electrocatalytic systems is that their electrochemically active centres contained within the polymer matrix exhibit a dual purpose. They must be efficient electron transporters (the layer must have reasonable electronic or redox conductivity) as well as display i.e., good inherent electrocatalytic activity. 

Polymers. Electronically conductive polymers may also be used as cathode materials in rechargeable lithium batteries. The most popular polymers are polyacetylene, polypyrrole, polyaniline, and polythiophene, which are made conductive by doping with suitable anions. The discharge-charge process is a redox reaction in the polymer. The low specific energy, high cost, and their instability, however, make these polymers less attractive. They have been used in small coin-type batteries with a lithium-aluminum alloy as the anode. 

When the conjugated polymers are oxidized or reduced, ionic sites (polarons, etc.) are formed by extracting electrons from (or injecting electrons into) the it system. These sites are mobile, particularly along the tt system, and render the polymer electronically conductive. However, they are confined to the polymer phase, i.e., they constitute bound charges that are nonexchangeable. Thus, they require counterions for charge compensa-... 

This article addresses the synthesis, properties, and appHcations of redox dopable electronically conducting polymers and presents an overview of the field, drawing on specific examples to illustrate general concepts. There have been a number of excellent review articles (1—13). Metal particle-filled polymers, where electrical conductivity is the result of percolation of conducting filler particles in an insulating matrix (14) and ionically conducting polymers, where charge-transport is the result of the motion of ions and is thus a problem of mass transport (15), are not discussed. 

The active layer consists of a polymer having electronic conductive, ionic conductive, and luminescent properties, is blended with an ionic salt [48]. The polymer with the required properties can be realized by a blend of a conjugated and an ionic conductive polymer [481 or by specially designed polymers [71-73],... 

Another model assumes that gel zones are formed by hydrated lead dioxide (PbO(OH)2) and act as bridging elements between the crystallite particles. Electrons can move along the polymer chains of this gel and so cause electronic conductivity between the crystalline zones 137],... 

Composite structures that consist of carbon particles and a polymer or plastic material are useful for bipolar separators or electrode substrates in aqueous batteries. These structures must be impermeable to the electrolyte and electrochemical reactants or products. Furthermore, they must have acceptable electronic conductivity and mechanical properties. The physicochemical properties of carbon blacks, which are commonly used, have a major effect on the desirable properties of the conductive composite structures. Physicochemical properties such as the surface... 

Rotations around torsional barriers induce changes in chain conformation. For conjugated systems like polydiacetylenes, flow-induced changes in chain conformation can have a profound influence on the photon absorption and electronic conductivity properties of the material [73]. Flow-induced changes in molecular conformation form the basis for several technically important processes, the best known examples are the production of oriented fibers by gel spinning [74], the compatibility enhancement [75] and the shear-induced modification of polymer morphology [76]. 

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