Showing papers on "Conductive polymer published in 1993"

Applications of electroactive polymers

Abstract: Preface. Electrical and electrochemical properties of ion conducting polymers. Electrical and electrochemical properties of electronically conducting polymers. Highly-conductive polymer electrolytes. Solvation mechanisms in low molecular weight polyethers. Lithium batteries with polymer electrodes. Lithium polymer batteries. Electrochromic devices. Laminated electrochromic displays and windows. Functionalized conductive polymer membranes/films. Electroactive polymers in chemical sensors.

Conductive polymer composition

Abstract: A conductive polymer composition which has low resistivity and good electrical stability. In one aspect the composition comprises a nonconductive filler which is a dehydrated metal oxide. In an another aspect the composition comprises a conductive filler which is metal particles in which the bulk density is less than 0.15 times the true density. Compositions of the invention are particularly useful for circuit protection devices (1).

Crystal Structure of the Polymer Electrolyte Poly(ethylene oxide)3:LiCF3SO3.

Abstract: Ionically conducting polymers (polymer electrolytes) are under intensive investigation because they form the basis of all solid-state lithium batteries, fuel cells, and electrochromic display devices, as well as being highly novel electrolytes. Little is known about the structures of the many crystalline complexes that form between poly(ethylene oxide) and a wide range of salts. The crystal structure is reported of the archetypal polymer electrolyte poly(ethylene oxide)(3):LiCF(3)SO(3), which has been determined from powder x-ray diffraction data. The poly(ethylene oxide) (PEO) chain adopts a helical conformation parallel to the crystallographic b axis. The Li(+) cation is coordinated by five oxygen atoms-three ether oxygens and one from each of two adjacent CF(3)SO(3)(-) groups. Each CF(3)SO(3)(-) in turn bridges two Li(+) ions to form chains running parallel to and intertwined with the PEO chain. There are no interchain links between PEO chains, and the electrolyte can be regarded as an infinite columnar coordination complex.

Synthesis of fusible and soluble conducting polyfluorene derivatives and their characteristics

Abstract: Conducting poly(9-alkylfluorene)s and poly(9,9-dialkylfluorene)s have been synthesized by chemical polymerization utilizing FeCl 3 as an oxidizing agent. The polymers obtained are found to be soluble in conventional organic solvents such as chloroform and have been characterized by 1 H- and 13 C-NMR. The results indicate that the fluorene moeities are mainly linked in the 2,7'-fashion to yield the straight chain polymer. The degree of polymerization is estimated (by GPC) to be of the order of 10. The polymers are found to be fusible and the thermal properties of the polymers have been characterized by DSC

Photoexcitation spectroscopy of conducting-polymer-C60 composites: Photoinduced electron transfer.

Abstract: We present a comparative study of the steady-state photoinduced absorption and photoinduced electron-spin-resonance (ESR) spectra of conducting polymers mixed with the fullerene ${\mathrm{C}}_{60}$. For conjugated polymers with nondegenerate ground states as donors, electron transfer takes place prior to either radiative or nonradiative recombination of \ensuremath{\pi}-electron photoexcitations on the conducting polymer. In the case of a conjugated polymer with a degenerate ground state as donor, the structural relaxation associated with the formation of charged solitons is faster; and no indications of photoinduced charge transfer are observed. Thus, composites using a derivative of poly(1,6-heptadyene) as donor do not exhibit long-lived charge separation, whereas charge transfer and charge separation are observed in composites using poly(p-phenylene vinylene) or polythiophene derivatives as donors. The relaxation (as a function of temperature) of the charge separated state is studied through photoinduced absorption spectroscopy (excitation spectroscopy) and photoinduced ESR. The results are discussed in terms of designing suitable donor-acceptor pairs for photoinduced electron transfer using conducting polymers and ${\mathrm{C}}_{60}$ as donor and acceptor, respectively.

Intrinsically conducting polymers : an emerging technology

Abstract: Preface. Synthesis, properties and applications of perconjugated systems H. Naarmann. Functionalizations of conducting polymers by mesoscopically structural control and by molecular combination of reactive moiety T. Shimidzu, T. Iyoda, H. Segawa, M. Fujitsuka. Characterization and application of polypyrrole-coated textiles H.H. Kuhn. Potential applications of conducting polymer colloids S.P. Armes. Processing of polyanilines V.G. Kulkarni. Inclusion of conducting polymers in inorganic hosts: towards conducting nanostructures T. Bein, P. Enzel. The separation of gases using conducting polymer films B.R. Mattes, M.R. Anderson, H. Reiss, R.B. Kaner. Intrinsically conducting polymers: from fundamental to applied research E. Genies. Conjugated polymer light-emitting diodes A.R. Brown, N.C. Greenham, R.W. Gymer, K. Pichler, D.D.C. Bradley, R.H. Friend, P.L. Burn, A. Kraft, A.B. Holmes. Molecular engineering of organic semiconductors F. Garnier, F. Deloffre, A. Yassar, G. Horowitz, R. Hajlaoui. Blue electroluminescence with polyconjugated materials G. Leising. Organic multilayer-dye electroluminescent diodes: is there any difference with polymer LED? T. Tsutsui, S. Saito. The chemical and electronic structure of metal/conjugated polymer interfaces: a joint theoretical and experimental study R. Lazzaroni, C. Fredriksson, A. Calderone, J.L. Bredas, P. Dannetun, M. Boman, S. Stafstrom, W.R. Salaneck. Application of conducting polyanilines in computer manufacturing M. Angelopoulos. Conducting polymers for molecular electronics S. Roth, J. Anders, H.J. Byrne. Polyanilines: recent advances in processing and applications to welding of plastics A.J. Epstein, J.Joo, C.-Y. Wu, A. Benatar, C.F. Faisst Jr.,j. Zegarski, A.G. MacDiarmid. Electrochemomechanical and electrochemopositioning devices: artificial muscles T.F. Otero, J. Rodriguez. A highly thermostable aluminum solid electrolytic capacitor with an electroconducting-polymer electrolyte Y. Kudoh, M. Fukuyama, T. Kojima, N. Nanai, S. Yoshimura. Polymer based xerographic photoreceptors M.A. Abkowitz. Subject index.

Synthesis and characterization of poly(aniline-co-o-anisidine) : a processable conducting copolymer

Abstract: An attempt has been made toward the chemical synthesis of poly(aniline-co-o-anisidine). It has been found that this conducting polymer is soluble in common organic solvents such as acetone, DMF, THF, and NMP at room temperature. The characterization of poly(aniline-co-o-anisidine) has been carried out using FTIR, UV-visible, DSC, and electrical conductivity measurements

Molecular recognition using conducting polymers: basis of an electrochemical sensing technology—Plenary lecture

Abstract: Molecular recognition principles are being increasingly used as the basis for analytical technologies. The combination of a molecular recognition approach with conducting polymer materials has been beneficial, particularly in the field of electrochemical sensing. The electrochemical sensing process usually consists of two steps: analyte recognition and signal generation. Conducting polymers are versatile materials in which molecular/analyte recognition can be achieved in a number of different ways, including the incorporation of counter ions that introduce selective interactions, using the inherent and unusual ion-exchange properties of the conducting polymers; the addition of functional groups to the monomers; and the codeposition of metals within the polymer. Specific examples of these approaches are provided. The molecular recognition properties of conducting polymers can be further refined by the application of appropriate electrochemical potentials, which can induce either large or small changes in the chemical interactions that occur at the polymers. This electroactivity, as well as their conducting properties, also provides the basis for the signal generation steps. A number of electronic signals relating to some chemical or electrochemical change within the polymer can be measured. These include the faradaic electron transfer typically used for electrochemical sensing, the catalysis of the analytically useful electron transfer by the polymer or the analyte, the change in capacitance signals induced by the analyte species and changes in the polymer resistance which can be measured by a recently developed technique. These features, combined with the molecular recognition properties, make conducting polymers a very promising material for electrochemical sensing technology.

Coupling of ion and electron transport during impedance measurements on a conducting polymer with similar ionic and electronic conductivities

Abstract: The ionic and electronic conductivities of poly-[1-methyl-3-(pyrrol-1-ylmethyl)pyridinium perchlorate] have been measured as a function of potential in various solvents by impedance spectroscopy. The ionic conductivity of this polymer shows a strong solvent dependence, ranging from 0.31 mS cm–1 in water to 8.0 µS cm–1 in propylene carbonate. By changing the solvent and the potential, the ionic to electronic conductivity ratio for the polymer has been varied from 1 to 1, allowing a thorough exploration of the validity of a dual resistance transmission line model of the polymer. Overall, the experimental results support the model, and reasonably accurate electronic and ionic conductivities are obtained when data are analysed according to the model. However, an anomalous dependence of ionic conductivity on oxidation state has been observed. There appears to be a direct relationship between the electronic and ionic conductivities of the polymer when they are of similar magnitude, indicating a coupling of ion and electron transport.

Mechanistic studies on the interactions between poly(pyrrole) and organic vapors

Abstract: Results relating to the application of conducting polymers as chemiresistors for the sensing of vapors are reported. In particular, we describe the use of a piezoelectric microbalance with gold electrodes on which we have electrochemically deposited a thin layer of poly(pyrrole). Uptake of a selection of common neutral organic vapors, covering a range of physical properties, is then measured at the same time as measurement of the resistance of a similar thickness of poly(pyrrole) deposited on a narrow-gap resistance probe. Mass uptake and resistance change are considered together to avoid masking the real trends caused by differences in polymer-solvent compatibilities

Electrical device comprising a conductive polymer composition

Abstract: A conductive polymer composition which has a resistivity of less than 10 ohm-cm and which exhibits PTC behavior comprises a polymeric component and a particulate conductive filler. The polymeric component comprises a first crystalline fluorinated polymer having a first melting point T m1 and a second crystalline fluorinated polymer having a second melting point T m2 which is from (T m1 +25)° C. to (T m1 +100)° C. The composition exhibits one of a number of characteristics, including a relatively high PTC anomaly. The composition is useful in circuit protection devices to be used at high ambient conditions.

Multi-layer conducting polymer gas sensor arrays for olfactory sensing

Abstract: Conductivity sensors using the conducting polymer poly(pyrrole) and its derivatives have been prepared with a novel electrode design which allows the probing of resistance changes within zones of a single sensor. It was found that the application of principal component analysis to the sensor responses allowed methanol, ethanol and propanol to be distinguished. The use of layered conducting polymers improved the discrimination of the sensor. A sensor consisting of four electrode pairs and two polymer layers is capable of separating the response of certain alcoholic beverages.

Electrical, structural and processing properties of electrically conductive adhesives

Abstract: There is growing interest in the potential of electrically conductive metal-loaded polymer adhesives. Eight commercial electrically conductive adhesive pastes for solder replacement in surface mount technology (SMT) and other microelectronic applications were selected for study, including both thermosetting and thermoplastic examples. All were silver based, except for one nickel-polymer composite. The properties on which this work was focused were the microstructure and electrical characteristics, with the specific purpose of determining the conduction mechanisms. The electrical measurements established that the primary source of electrical resistance is in the silver particles, with negligible contact effects between them. Differential scanning calorimetry results indicated that drifts in the electrical properties are not attributable to incomplete cures. Electrical measurements on simplified structures prepared in the laboratory are also reported. >

Water-based polymer thick film conductive ink

Abstract: The present invention relates to an aqueous conductive polymer thick film-forming composition comprising a water-soluble thermoplastic polymer, a polymer dispersion in water, a glycol drying-retarder agent, an electrically conductive amount of conductive metal and/or carbon particles and water. The composition in the production of a highly printable conductive thick film ink.

Electrochemistry of Conductive Polymers XIV . In Situ Spectroelectrochemical and Kinetic Studies on Poly(3‐Methylthiophene) Growth

Abstract: The growth mechanism of poly(3-methylthiophene) has been studied employing in situ spectroelectrochemical and kinetic measurements. Results indicate that: (1) the polymer film grows only when 3-methylthiophene is oxidized, suggesting that the radical-radical coupling reaction is important for the polymer growth; (2) concentrations of intermediate species, i.e., radical cations of the trimer and tetramer, are maintained at a steady-state level during the growth; and (3) both monomer and polymer concentrations appear in the rate expression, indicating that both the monomer and polymer participate in the polymer growth. The growth is not autocatalytic, and oxidation of both the monomer and polymer participate in the polymer growth. The growth is not autocatalytic, and oxidation of both the monomer and oligomer or polymer is required for further growth of the polymer. The reaction order in the rate expression depends on experimental conditions ranging 0.5 [approximately] 1 for the monomer, while it is about 0.5 for the polymer.

High ionic conductivity of new polymer electrolytes consisting of polypyridinium, pyridinium and aluminium chloride

Abstract: Polymer complexes consisting of polypyridinium, pyridinium and aluminium chloride are found to be a new class of highly conductive polymer electrolytes, which exhibit a high ionic conductivity of 10–3 S cm–1 at room temperature within range of the conductivity of electrolyte solutions, in spite of film-forming properties.

Conductive Blends of π-Conjugated Polymers and Thermoplastic Polymers in Latex Form

Abstract: By using Fe(III)-, Fe(II)-, or Cu(II)-H2O2 oxidation systems, latex form conductive blends of thermoplastic polymer with π-conjugated polymer, such as polyaniline, polypyrrole, and poly(3-methoxythiophene) were prepared via in situ polymerization in aqueous media containing latex particles. The oxidation system did not give apparent disturbance to the stability of the latex. Morphology study carried out by SEM and TEM showed that the latex polymer particles were uniformly coated by π-conjugated polymer even at relatively low π-conjugated polymer content (4 wt%). Parameters (pH, oxidant concentration, etc.) affecting the preparation and morphology of the blends were examined. The blend recovered by removing water by evaporation showed electrical conductivity of 0.02–0.92 S cm−1.