Showing papers on "Conductive polymer published in 1982"

Ab initio effective Hamiltonian study of the electronic properties of conjugated polymers

Abstract: The valence effective Hamiltonian technique is applied to a series of polymers to compute ionization potentials, bandwidths, and band gaps. The polymers considered represent systems of interest to the conducting polymers area and include various derivatives of polyacetylene and polyphenylene, polydiacetylene, polyacene, polybenzyl, and polyyne. The theoretical results for relative ionization potentials are in excellent agreement with available experimental estimates, as well as with the observed behavior of the electrical conductivity of these systems on exposure to weak (I2) versus strong (AsF5) electron acceptors. The bandwidths of the highest occupied band show a qualitative correlation to the conductivities achieved with acceptor doping. Band gaps for the planar systems considered are also in good agreement with experiment.

Electrical Properties of Conducting Polymer, Poly-Thiophene, Prepared by Electrochemical Polymerization

Abstract: Poly-thiophene perchlorate is prepared electrochemically in an electrolyte of 0.5 M AgClO4 and 0.2 M thiophene in acetonitrile. Dark greenish film with the complex of ca. [C4H2S(ClO4)0.26]x is obtained. The electrical conductivity along the film surface is about 0.6 Ω-1cm-1.

Corrosion protection method

Abstract: Methods of preventing corrosion in which current flows between the to-be-protected substrate and a distributed electrode whose electrochemically active surface is provided by an element which is composed of a conductive polymer and which is at least 500 microns thick. In one embodiment, the electrode is a flexible strip comprising a highly conductive core, e.g. of copper, and a conductive polymer element surrounding the core. In another embodiment, the electrode is a conductive polymer layer which conforms to the surface of the substrate but is separated from it by a layer of insulation.

Poly(p-Phenylene Sulfide) Hexafluoroarsenate: A Novel Conducting Polymer.

Abstract: : Poly(p-phenylene sulfide) (PPS) is a melt and solution processible polymer which on treatment with AsF5 forms a blue-black material with a conductivity of 1 to 10/ohm cm. Thermopower measurements indicate that the resulting polymer is p-type, consistent with partial oxidation of the PPS by the AsF5. The rate and extent of this doping process prove to be particularly sensitive to the degree of crystallinity of the starting polymer. There is no evidence of crosslinking of the polymer chains during the reaction with AsF5. The details of both the chemistry and physics of the doping of PPS and several of its derivatives are presented. (Author)

Oxygen evolution on tantalum–polypyrrole–platinum anodes

Abstract: Electrically conducting polymer films of polypyrrole were previously reported1–6 to provide greatly enhanced stability against the photodegradation of semiconductor photoanodes in electrochemical photovoltaic cells. To determine the feasibility of protecting photoanodes with polypyrrole in photoelectrolysis cells where O2 is evolved some basic questions had to be answered. To achieve this we have performed experiments using polypyrrole films as protective coatings on Ta metal electrodes; Ta is known to form insulating oxides that prevent O2 evolution from aqueous solution. We found that polypyrrole is stable in the presence of O2; that while polypyrrole itself is a poor electrocatalyst for O2 evolution, metal catalysts can be deposited on its surface to enhance O2 evolution; and that Ta–polypyrrole–Pt electrode structures are electrochemically indistinguishable from naked Pt electrodes with respect to O2 evolution.

Electrically conducting polymers

Abstract: The polymers resulting from reaction of a α,α,α',α'-tetrahaloxylene with a diamine of the type H2 NANH2, where A is a divalent aromatic moiety, may be doped with a variety of materials to afford electrically conducting polymeric compositions. Both p-type and n-type conductors may be formed either by chemical or electrochemical doping procedures.

Photoelectrochemical cells for conversion of solar energy to electricity and methods of their manufacture

Abstract: A photoelectric device is disclosed which comprises first and second layers of semiconductive material, each of a different bandgap, with a layer of dry solid polymer electrolyte disposed between the two semiconductor layers. A layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte is further interposed between the dry solid polymer electrolyte and the first semiconductor layer. A method of manufacturing such devices is also disclosed.

Radiation cross-linking of PTC conductive polymers

Abstract: The higher the voltage applied to an electrical device comprising a PTC conductive polymer, the more likely it is that intermittent application of the voltage will cause the device to fail. According to the invention, the likelihood of such failure is substantially reduced by irradiating the PTC conductive polymer (1) so that it is very highly cross-linked, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, especially at least 120 Mrads. In this way, for example, it is possible to make a circuit protection device which will continue to provide effective protection even after repeated exposure to a voltage of 200 volts.

Polymer blends for use in photoelectrochemical cells for conversion of solar energy to electricity and methods for manufacturing such blends

Abstract: There is disclosed a polymer blend of a highly conductive polymer and a solid polymer electrolyte that is designed to achieve better charge transfer across the conductive film/polymer electrolyte interface of the electrochemical photovoltaic cell. The highly conductive polymer is preferably polypyrrole or poly-N-p-nitrophenylpyrrole and the solid polymer electrolyte is preferably polyethylene oxide or polypropylene oxide.

Solution of a chalcogen-containing polymer and process of forming conducting polymer articles therefrom

Abstract: A polymer solution is formed from a sulfur- or oxygen-containing aromatic polymer solute such as poly(phenylene sulfide) or poly(phenylene oxide), a Lewis Acid solute derivative (dopant) such as arsenic hexafluoride and a liquid halide solvent such as arsenic trifluoride. The solutions are especially useful for casting conductive polymer articles.

Conductive polymers formed by ion implantation

Abstract: Conductive materials are formed by implanting high energy ions (30 keV to 300 keV) into rigid backboned polymers, such as poly (p-phenylene sulfide); conductivities on the order of 10-3 (ohm-cm)-1 are demonstrated and the materials remain stable over periods as long as a year

Photoelectrochemical solar cells: Stabilization of small band GAP semiconductor in aqueous solution by surface-attached organic conducting polymer

Abstract: Surface-attached polypyrrole films have been shown to produce a marked improvement in the stability of n-type single-crystal and polycrystalline Si against oxidation in an aqueous electrolyte. The current production of n-type polycrystalline Si coated with polypyrrole deteriorates less than 30% during 122 hr of irradiation whereas the unprotected bare electrode stops producing photocurrent within 30 s. The polymer protection of the n-type single-crystal Si is significantly less than that of the polycrystalline material because of differences in the adhesion of the polymer film to the electrode surfaces. The adhesion strength is shown to depend on various surface properties of Si and other electrode materials. Moreover, the surface morphology of the electrode affects the topography of the growing surface of the polypyrrole film. Requirements are discussed for the applications of organic conducting polymers to photoelectrochemical devices utilized for solar energy conversion.

Heating Diesel fuel

Abstract: Conductive polymer compositions based on polyvinylidene fluoride have improved properties when the polyvinylidene fluoride has a very regular structure characterized by a low head-to-head content in the repeating units. The improved properties include improved electrical stability when contacted by organic fluids and/or when maintained at elevated temperatures in air. Such compositions are particularly useful in the form of self-limiting heaters, e.g. for heating diesel fuel.

The morphology and structure of highly conducting polymers

Abstract: A review on the morphology and structure of highly conducting polymers is presented. As a special case the inorganic polymer polysulfur nitride is mentioned in the introduction. The main part of the review is concerned with polyacetylene doped by diffusion of impurities or electrochemically. Applications for light weight batteries and low cost solar cells are briefly treated. The final section deals with doped polyparaphenylen polyparaphenylensulfide, and polypyrrol and the soliton type of conduction in lightly doped polyacetylene.

End seal for conductive polymer devices

Abstract: An improved end seal (220) is made at the cut end of a cut-to-length conductive polymer heater (10) by extruding the conductive polymer (14) so that it encapsulates the end of at least one of the electrodes (12).

Stabilization of conductive polymers in aqueous environments

Abstract: Polyacetylene, doped with iodine, can be stabilized against aqueous deterioration by immersion in moderately concentrated chloride solutions.

The effects of pressure on the ionic conductivity of PEO 8 -LiClO 4

Abstract: Ion conducting polymers are currently being considered for use as the solid state electrolyte in batteries. The feasibility of such an application has been shown by several workers [1-5]. They show that conductivities of the order of 10–4/ohm-cm can be obtained. This is sufficient to achieve the desired power densities of about 100 W/l, since polymers can be formed into very thin layers. The purpose of the present work is to report data concerning the effect of pressure on the ionic conductivity of these materials. The results are used to calculate the activation volume for the motion of the ions which yields new information concerning ion transport.