Showing papers on "Conductive polymer published in 1988"

Electrochemistry of Conductive Polymers II . Electrochemical Studies on Growth Properties of Polyaniline

Abstract: Details of the growth properties of polyaniline (PA) have been studied employing electrochemical techniques (potential cycling method) and the results are reported. The electrochemical growth may be characterized as autocatalytic, and the growth rate is first order in aniline concentration. The growth rate is also dependent on the amount of PA film on the electrode as well as the number of potential cycles. The highest oxidized PA, attacked by an aniline molecule, grows to a longer chain, and a net reduction of the PA film upon aniline addition would render the film conducting. This mechanism explains why the film continues to grow at potentials where only passivating behavior would be predicted. In addition, the growth was divided into regions of well‐defined and poorly defined (amorphous) phases; at longer oxidation times during growth, side reactions seem to play more important roles compared to the earlier phase of the growth process.

Field‐effect mobility of poly(3‐hexylthiophene)

Abstract: A field‐effect transistor structure is used to study the transport properties of the soluble conductive polymer, poly(3‐hexylthiophene). We have measured conductance, mobility, and carrier concentration in undoped polymer thin films. The field‐effect mobility was found to be 10−5–10−4 cm2/V s at room temperature. The mobility decreases with increased temperature. The change is only partly reversible. Possible transport models are discussed.

Electrochemistry of Conductive Polymers III . Some Physical and Electrochemical Properties Observed from Electrochemically Grown Polyaniline

Abstract: Some of the physical and chemical properties of electrochemically grown polyaniline (PA) films have been studied and results are reported. Physical properties determined include the density of PA sulfate (1.5 g/cm3), empirical equations relating the film thickness with electrical charges measured during the film growth, cyclic voltammetric peak potentials, or the amount of benzoquinone recovered after the degradation reaction, and spectral absorptivity of reduced PA at its absorption band maximum ( depending on the medium). Elemental analysis results as well as stability factors determined during the potential cycling in various electrolyte solutions are presented as part of some chemical properties.

Electrodeposition of platinum microparticles into polyaniline films with electrocatalytic applications

Abstract: The electrodeposition of platinum microparticles into polyaniline (PA) films on glassy carbon (gc) electrodes and their catalytic activity for the reduction of hydrogen and the oxidation of methanol are described. Electrodeposited platinum microparticles are dispersed in a three-dimensional array in fibril-type polyaniline film electrodes as evidenced by scanning electron microscope photomicrographs. These Pt/PA/gc electrodes exhibit good activity with respect to the catalytic reduction of hydrogen and the catalytic oxidation of methanol. Since polyaniline is a conducting polymer at potentials positive of 0.2 V vs Ag/AgCl, the PA films contribute a substantial amount of charge during the oxidation of methanol at 0.6 V. In addition, they also offer a protecting matrix for the Pt microparticles against particle loss and contamination from the bulk solution. The electrodes exhibited excellent long-term stability in the acidic methanol solutions.

A class of conducting polymers having nonconjugated backbones

Abstract: Avec des substituants appropries des polymeres non conjugues peuvent aussi former des complexes conducteurs

Plastics that conduct electricity

Abstract: Conducting polymers combine the electrical properties of metals with the advantages of plastics. Ordinary polymers have the electronic profile of insulators and semiconductors. To make polymers conduct electricity, small quantities of certain chemicals are incorporated into the polymer by a process called doping. In 1977, the first conducting polymer was synthesized; in 1981, the first battery with polymer electrodes was demonstrated. Last summer, conducting polymers matched the conductivity of copper. Conducting polymers also have interesting optical, mechanical, and chemical properties that taken together with their ability to conduct might make them effective in novel applications. 5 figs.

Intrinsically conductive polymer in the form of a dispersible solid, its manufacture and its use

Abstract: An intrinsically conductive polymer is in the form of a dispersible solid of primary particles with a specific surface area according to BET of > 15m2/g and with an average diameter of less than 500 nm, in which preferably not more than 20 % of aggregates with an average size > 1 mum are present in the particle size range > 500 nm. For the manufacture of the polymer the polymerisation is carried out in a solvent in which the appropriate monomer is soluble or colloidally dispersible, but in which the polymer that is formed is insoluble, whereby the temperature of the reaction mixture is not allowed to rise more than 5°C above the starting temperature.

Electrochemical Behaviors of Polypyrrole, Poly‐3‐methylthiophene, and Polyaniline Deposited on Nafion‐Coated Electrodes

Abstract: Anodic polymerization of pyrrole, 3‐methylthiophene, and aniline at Nafion‐coated electrodes gives conducting polymer‐Nafion composite films The composite films show better reversibility in the film redox process than conducting polymer films alone, owing to different charge compensation mechanisms in the redox reaction; electrolyte cations are involved in the redox process of the composite films, whereas electrolyte anions are in the ordinary conducting polymers The fast kinetics of the redox process of the composite films are effectively demonstrated by an improvement of the polypyrrole electrochromic response and by the efficient utilization of stored charge by the composite film electrodes

Poly-1,2-azepines by the photopolymerization of phenyl azides. Precursors for conducting polymer films

Abstract: Polymers with a 1,2-azepinediyl structure are the primary products in the photopolymn. of aryl azides in a N atm. The polymers are through to be formed via singlet phenylnitrene and azacycloheptatetraene. The structure elucidation of these polymers is based on both spectroscopy and chem. anal. using a series of seven (substituted) Ph azides. The initially formed poly-1,2-azepines are very susceptible to oxidn.; delocalized charge species are formed upon exposure to air, while upon oxidative doping with I2 or AsF5 the polymers become elec. conductive. Conductivities ?10-2 S/cm are found. When the photopolymn. of aryl azides is performed in air, a simultaneous photooxidn. of the poly-1,2-azepines is obsd., furnishing carbonyl contg. polymers. Thin polymer films of poly-1,2-azepines are deposited on a fused silica window when the photopolymn. is carried out with gaseous PhN3. High-resoln. patterns of poly-1,2-azepines are formed when a photomask is used in this gas-phase polymn. Upon doping these patterns become elec. conductive. [on SciFinder (R)]

Synthesis of electroactive/conductive polymer films: electrooxidation of heteroaromatic compounds

Abstract: Preparation a partir de derives du pyrrole, thiophene, carbazole, azulene, pyrene, triphenylene et aniline. Revue des caracteristiques de la polymerisation electrolytique et des proprietes des films

Production of highly conductive polymers for electronic circuits

Abstract: Processes for producing stable, radiation hard, highly conductive polymers by a combination of chemical doping and ion irradiation and microelectronics are described. The highly conductive polymers formed by these processes may contain regions of different kinds of conductivity on the same polymer. Resist coatings and masks are used in conjunction with chemical doping and ion irradiation to create specific predetermined n and p conductivity patterns and insulation areas on polymeric films of selected thicknesses for electronic circuitry applications. The resulting circuitry, besides having a conductivity approaching that of metal, is extremely light in weight, flexible, and conductively stable. Several different configurations of microelectronic junction devices fabricated from single type or multiple type conductivity polymer films used either alone or with a polymer of opposite conductivity and a suitable metal or metals are disclosed.

Conductive polymer materials and method of producing same

Abstract: Production of base-type conductive polymers, particularly from the family of conductive polyaniline, by reacting a base-type non-conductive polymer containing carbon-nitrogen linkages, e.g., polyaniline, with an anhydride, such as R-SO2-O-SO2-R', R-CO-O-CO-R', or R-CO-O-SO2R', or mixtures thereof, where R and R' are alkyl or aryl, e.g., tosylic anhydride or benzophenone tetracarboxylic dianhydride, and forming an electrically conductive polymer in which the SO2R and COR groups are covalently linked to the nitrogen atoms of the conductive polymer and the anion of the conductive polymer is the SO3R' or O2CR' group.

Conducting polymers by ion implantation

Abstract: An electrically conductive surface can be created by using the ion implantation process on nonconducting polymeric sheet. The resulting conductivity was measured and correlated to ion beam parameters, such as ion species, dose, and energy. Additionally, a reaction model, in both physical and chemical terms, was proposed, which can assist in understanding of the underlying mechanisms during the ion implantation of polymers. The surface microscopic structure of the ion-implanted polymer specimens was evaluated by X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), Rutherford backscattering spectroscopy (RBS), and infrared spectroscopy (IR). The experimental results indicated that the ion bombardment process leads to a carbon-enriched material in a manner akin to the carbonization of organic films observed upon pyrolytic processing.

Electrically heated structural composite and method of its manufacture

Abstract: An electrically conductive structural composite which can be heated by application of an electrical current The structural composite includes a plurality of layers of structural fabric which have been treated and prepreged with a laminating resin and cured into a laminate structure At least one of the layers of fabric is rendered conductive by being treated with conductive polymer produced by the steps of contacting an electrically insulating porous structural fabric with a liquid pyrrole; contacting the electrically insulating porous structural fabric with a solution of a strong oxidant capable of oxidizing pyrrole to a pyrrole polymer; and, oxidizing the pyrrole by the strong oxidant in the presence of a substantially non-nucleophilic anion and precipitating a conductive pyrrole polymer in the pores of the structural fabric Electrical conducting means in electrical contact with the conductive layer are utilized for providing passage of electrical current for joule heating of the structural composite The structural composite has been found to be particularly useful as an airplane surface which is capable of anti-icing and de-icing

Conductive polymers with immobilised dopants: ionomer composites and auto-doped polymers-a review and recent advances

Abstract: The electrodeposition of poly(pyrrole) in the presence of a polyanionic electrolyte (poly(styrenesulphonate), poly(vinylsulphate) or Nafion) leads to the formation of a film of a composite polymer at the surface of the two polymeric structures prevents the anionic dopants from being expelled during the dedoping, consequently cations are inserted. This cation-exchange behaviour is the origin of applications in the field of charge-controllable membranes such as water deionisation and the polymer battery, reported by Shimidzu and co-workers (1987). The immobilisation of the anionic dopant has also been achieved by their direct covalent binding to the conductive polymer backbone, leading to the concept of internal doping or 'auto-doping'. The poly(3-alkylsulphonate-thiophenes) (1987) reported by Wudl, Heeger and co-workers (187) are revealed to be the first water-soluble conductive polymers. A study of the poly(3-methylpyrrole-4-carboxylic acid) by Pickup (1987) shows that the formal potential of this polymer is sensitive to pH. The copoly(pyrrole+N-alkylsulphonate-pyrrole) presented by the authors in more detail exhibits a remarkable mixed behaviour as a result of the coupling of cationic membrane with conductive polymer properties. In particular, the electrochemical behaviour of this co-polymer is very sensitive to the water content of the solvent.

Water-soluble conductive polymers

Abstract: Polymers which are soluble in water and are electrically conductive. The monomer repeat unit is a thiophene or pyrrole molecule having an alkyl group substituted for the hydrogen atom located in the beta position of the thiophene or pyrrole ring and having a surfactant molecule at the end of the alkyl chain. Polymers of this class having 8 or more carbon atoms in the alkyl chain exhibit liquid crystalline behavior, resulting in high electrical anisotropy. The monomer-to-monomer bonds are located between the carbon atoms which are adjacent to the sulfur or nitrogen atoms. The number of carbon atoms in the alkyl group may vary from 1 to 20 carbon atoms. The surfactant molecule consists of a sulfonate group, or a sulfate group, or a carboxylate group, and hydrogen or an alkali metal. Negative ions from a supporting electrolyte which may be used in the electrochemical synthesis of a polymer may be incorporated into the polymer during the synthesis and serve as a dopant to increase the conductivity.

Towards chiral metals. Synthesis of chiral conducting polymers from optically active thiophene and pyrrole derivatives

Abstract: The synthesis of free standing and clay-supported chiral conducting polymer films is described.

Conductive polymer-polyimide blends and method for producing same

Abstract: A conductive polymer blend which comprises mixing a polyimide with a base-type polymer containing carbon-nitrogen linkages, such as polyaniline, having a polyimide-like group covalently linked to nitrogen atoms of the base-type polymer. The conductive polymer blend is formed by first reacting a base-type non-conductive polymer containing carbon-nitrogen linkages, such as polyaniline, with a carbonyl anhydride, such as 3,3',4,4'-benzophenone tetracarboxylic dianhydride, to form a conductive polymer containing polyimide-like groups covalently linked to nitrogen atoms of the base-type polymer, mixing such conductive polymer with non-conductive polyimide in a suitable solvent, removing the solvent, and forming a conductive continuous phase blend of the polyimide and the conductive polymer.