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Sample records for nanocrystal conducting polymer

  1. Nanocrystal: Conducting Polymer Solar Cells via a New Synthetic Route

    CERN Document Server

    Watt, A A R; Meredith, H; Watt, Andrew A. R.; Blake, David; Meredith, Halina Rubinsztein-Dunlop & Paul

    2004-01-01

    In this letter we report photovoltaic devices fabricated from PbS nanocrystals and the conducting polymer MEH-PPV. This composite material was produced via a new single-pot synthesis which solves many of the issues associated with existing methods. Our devices have white light power conversion efficiencies under AM1.5 illumination of 0.7%.

  2. Semiconductor-nanocrystal/conjugated polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2014-06-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  3. Semiconductor-nanocrystal/conjugated polymer thin films

    Science.gov (United States)

    Alivisatos, A. Paul (Oakland, CA); Dittmer, Janke J. (Munich, DE); Huynh, Wendy U. (Munich, DE); Milliron, Delia (Berkeley, CA)

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  4. Optical spectroscopic studies of composites of conducting PANI with CdSe and ZnO nanocrystals

    Science.gov (United States)

    Bhat, S. V.; Vivekchand, S. R. C.

    2006-12-01

    Composites of CdSe and ZnO nanocrystals with conducting polyaniline have been prepared and investigated by optical spectroscopic method. A decrease in nanocrystal photoluminescence has been observed with the increase in the concentration of the polymer in the composites. The study shows that polyaniline causes the quenching of the nanocrystal luminescence.

  5. Thermally conductive polymers

    Science.gov (United States)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (inventors)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  6. Polyaniline: a conducting polymer.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Trchová, Miroslava

    Busan : IUPAC, 2015. MT-P0373-MON. [World Chemistry Congress /45./. 09.08.2015-14.08.2015, Busan] R&D Projects: GA MŠk(CZ) LG13037 Institutional support: RVO:61389013 Keywords : conductivity * conducting polymers * polyaniline Subject RIV: CD - Macromolecular Chemistry

  7. Spectroscopy of conducting polymers.

    Czech Academy of Sciences Publication Activity Database

    Trchová, Miroslava; Stejskal, Jaroslav

    Busan : IUPAC, 2015. MT-P0387-MON. [World Chemistry Congress /45./. 09.08.2015-14.08.2015, Busan] R&D Projects: GA MŠk(CZ) LG13037 Institutional support: RVO:61389013 Keywords : vibration spectroscopy * conducting polymers * polyaniline Subject RIV: CD - Macromolecular Chemistry

  8. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld; Wallace, Gordon

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped...

  9. Conductive Polymer Composites

    OpenAIRE

    Pierini, Filippo

    2013-01-01

    In recent years, nanotechnologies have led to the production of materials with new and sometimes unexpected qualities through the manipulation of nanoscale components. This research aimed primarily to the study of the correlation between hierarchical structures of hybrid organic-inorganic materials such as conductive polymer composites (CPCs). Using a bottom-up methodology, we could synthesize a wide range of inorganic nanometric materials with a high degree of homogeneity and purity, ...

  10. Superstructures of PbS nanocrystals in a conjugated polymer and the aligning role of oxidation.

    OpenAIRE

    Stavrinadis, A.; Xu, S; Warner, JH; Hutchison, JL; Smith, JM; Watt, AA

    2009-01-01

    We present a method to directly align PbS nanocrystals in micron-sized superstructures within a conjugated polymer. First, lead sulfide nanocrystals are directly synthesized in a MEH-PPV suspension via a single pot, surfactant-free method. Post-synthesis precipitation of the composite solution involving mild oxidation of the nanocrystals results in the formation of nanocrystal-polymer and nanocrystal-oxide superstructures. Detailed TEM is used to study the crystallographic nature of these str...

  11. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi; Castillo, Jaime; Emnéus, Jenny; Svendsen, Winnie Edith

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence...

  12. Conductivity and superconductivity in polymers

    International Nuclear Information System (INIS)

    Most of the paper is concerned with the mechanism of conduction in organic materials, and properties of particular classes of organic conductor. The final section reviews about 20 papers on attempts to prepare superconducting organic polymers. Following the general introduction, the sections are entitled: molecular conductivity, conjugated molecules, charge-transfer complexes, radical ions, radical cations, photoconduction, organometallic polymers, superconduction, conclusions. (U.K.)

  13. Conductive polymer-based material

    Science.gov (United States)

    McDonald, William F. (Utica, OH); Koren, Amy B. (Lansing, MI); Dourado, Sunil K. (Ann Arbor, MI); Dulebohn, Joel I. (Lansing, MI); Hanchar, Robert J. (Charlotte, MI)

    2007-04-17

    Disclosed are polymer-based coatings and materials comprising (i) a polymeric composition including a polymer having side chains along a backbone forming the polymer, at least two of the side chains being substituted with a heteroatom selected from oxygen, nitrogen, sulfur, and phosphorus and combinations thereof; and (ii) a plurality of metal species distributed within the polymer. At least a portion of the heteroatoms may form part of a chelation complex with some or all of the metal species. In many embodiments, the metal species are present in a sufficient concentration to provide a conductive material, e.g., as a conductive coating on a substrate. The conductive materials may be useful as the thin film conducting or semi-conducting layers in organic electronic devices such as organic electroluminescent devices and organic thin film transistors.

  14. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  15. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  16. Culture experiments on conductive polymers

    International Nuclear Information System (INIS)

    Fibroblast L929 and myoblast C2C12 cells of the mouse connective tissue origin were sown on the surface of conductive polymer films (polypyrrole, PPy and poly(3,4-ethylenedioxythiophene), PEDOT) in the cell culture medium, and the proliferative process of these cells was observed. Without changing the form, fibroblast L929 and myoblast C2C12 cells were observed to proliferate almost similarly to the cell which cultured on a dish on the market and to maintain compatibility. In other word, it has been understood these two kinds of conductive polymers used in this study, the PEDOT films maintain the secretion function of the cell cultured on the surface of these polymers. Therefore, the PPy- and the PEDOT-coated electrode suggested the possibility usable as a nerve stimulation electrode with biocompatibility, because these polymers were effective to culture the cell.

  17. Superstructures of PbS nanocrystals in a conjugated polymer and the aligning role of oxidation

    International Nuclear Information System (INIS)

    We present a method to directly align PbS nanocrystals in micron-sized superstructures within a conjugated polymer. First, lead sulfide nanocrystals are directly synthesized in a MEH-PPV suspension via a single pot, surfactant-free method. Post-synthesis precipitation of the composite solution involving mild oxidation of the nanocrystals results in the formation of nanocrystal-polymer and nanocrystal-oxide superstructures. Detailed TEM is used to study the crystallographic nature of these structures and the roles of polymer and lead sulfate. An epitaxial relationship between lead sulfide and lead sulfate at the nanoscale is shown, giving insight into the oxidation rates of the PbS nanocrystals' facets.

  18. Nanocrystal-polymer nanocomposite electrochromic device

    Energy Technology Data Exchange (ETDEWEB)

    Milliron, Delia; Runnerstrom, Evan; Helms, Brett; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2015-12-08

    Described is an electrochromic nanocomposite film comprising a solid matrix of an oxide based material, the solid matrix comprising a plurality of transparent conducting oxide (TCO) nanostructures dispersed in the solid matrix and a lithium salt dispersed in the solid matrix. Also described is a near infrared nanostructured electrochromic device having a functional layer comprising the electrochromic nanocomposite film.

  19. Synthesis and characterization of carbon nanotubes covalently functionalized with amphiphilic polymer coated superparamagnetic nanocrystals

    OpenAIRE

    Bear, JC; McNaughter, PD; Jurkschat, K; Crossley, A.; Aldous, L; Compton, RG; Mayes, AG; Wildgoose, GG

    2012-01-01

    Herein, we report the synthesis of three covalently linked superparamagnetic nanocrystal-multi-walled carbon nanotube (MWCNT) composites. A generic strategy for amphiphilic polymer coating of nanocrystals and further functionalization for amide bond formation with the MWCNTs is discussed. This approach can in principle allow attachment of any colloidal nanocrystal to the MWCNTs. The materials were characterized at each stage of the syntheses using DLS, zeta-potential measurements, FT-IR, TEM,...

  20. Water-soluble conductive polymers

    Science.gov (United States)

    Aldissi, Mahmoud (Sante Fe, NM)

    1990-01-01

    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.

  1. Optical Gain from InAs Nanocrystal Quantum Dots in a Polymer Matrix

    CERN Document Server

    Chen, G; Fuchs, D; Vilan, S; Aharoni, A; Banin, U; Chen, Gang; Rapaport, Ronen; Fuchs, Dan; Vilan, Sahar; Aharoni, Assaf; Banin, Uri

    2005-01-01

    We report on the first observation of optical gain from InAs nanocrystal quantum dots emitting at 1.55 microns based on a three-beam, time resolved pump-probe technique. The nanocrystals were embedded into a transparent polymer matrix platform suitable for the fabrication of integrated photonic devices.

  2. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    S S Sekhon

    2003-04-01

    Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.

  3. Electrically conductive polymer concrete coatings

    Science.gov (United States)

    Fontana, Jack J. (Shirley, NY); Elling, David (Centereach, NY); Reams, Walter (Shirley, NY)

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  4. Electrically conducting polymers for aerospace applications

    Science.gov (United States)

    Meador, Mary Ann B.; Gaier, James R.; Good, Brian S.; Sharp, G. R.; Meador, Michael A.

    1991-01-01

    Current research on electrically conducting polymers from 1974 to the present is reviewed focusing on the development of materials for aeronautic and space applications. Problems discussed include extended pi-systems, pyrolytic polymers, charge-transfer systems, conductive matrix resins for composite materials, and prospects for the use of conducting polymers in space photovoltaics.

  5. Molecular and supramolecular orientation in conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Aldissi, M.

    1987-01-01

    Intrinsic anisotropy in electrical and optical properties of conducting polymers constitutes a unique aspect that derives ..pi..-electron delocalization along the polymer backbone and from the weak inter-chain interaction. To acquire such an intrinsic property, conducting polymers have to be oriented macroscopically and microscopically (at the chain level). A review of the various techniques, including stretch-alignment of the polymer and of precursor polymers, polymerization in ordered media, i.e., in a liquid crystal solvent, and synthesis of liquid crystalline conducting polymers will be given. 29 refs.

  6. Molecular and supramolecular orientation in conducting polymers

    International Nuclear Information System (INIS)

    Intrinsic anisotropy in electrical and optical properties of conducting polymers constitutes a unique aspect that derives ?-electron delocalization along the polymer backbone and from the weak inter-chain interaction. To acquire such an intrinsic property, conducting polymers have to be oriented macroscopically and microscopically (at the chain level). A review of the various techniques, including stretch-alignment of the polymer and of precursor polymers, polymerization in ordered media, i.e., in a liquid crystal solvent, and synthesis of liquid crystalline conducting polymers will be given. 29 refs

  7. A merocyanine-based conductive polymer

    OpenAIRE

    Wagner, Klaudia; Zanoni, Michele; Elliott, Anastasia B.S.; Wagner, Pawel; Byrne, Robert; Florea, Larisa; Diamond, Dermot; Gordon, Keith; Wallace, Gordon; Officer, David

    2013-01-01

    We report the first example of a conducting polymer with a merocyanine incorporated into the polymer backbone by electropolymerisation of a spiropyran moiety covalently linked between two alkoxythiophene units. Utilising the known metal coordination capabilities of merocyanines, introduction of cobalt ions into the electropolymerisation led to an enhancement of the conductivity, morphology and optical properties of the polymer films.

  8. Integration of conducting polymer network in non-conductive polymer substrates

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; West, Keld; Hassager, Ole; Larsen, Niels Bent

    2006-01-01

    Anew method for integration ofconjugated, inherently conducting polymers into non-conductive polymer substrates has been developed. Alayer of the conducting polymer is polymerised by chemical oxidation, e.g. using Fe(ID) p-toluene sulfonate (ferri tosylate) followed by washing with a solvent which simultaneously removes residual and spent oxidant and at the same time dissolves the top layer of the polymer substrate. This results in an integration of the conducting polymer into the surface layers...

  9. Nonconjugated Conductive Polymers; Nonlinear Optical Effects

    Science.gov (United States)

    Thakur, Mrinal

    2011-10-01

    Nonconjugated conductive polymers are polymers with at least one double bond per repeat unit and having a double-bond number fraction less than 1/2 along the polymer backbone. In this presentation, recent results on nonlinear optical properties of nonconjugated conductive polymers will be discussed. Exceptionally large (the largest known) quadratic electro-optic effect and two-photon absorption coefficients have been recently reported for doped nonconjugated conductive polymers including: cis-polyisoprene (natural rubber), poly(?-pinene), trans-polyisoprene, and others. These large nonlinearities have been attributed to the nanometallic-like structures with subnanometer domains which are formed upon doping and charge-transfer involving nonconjugated conductive polymers. Various applications of nonconjugated conductive polymers such as in sensors, rechargeable batteries, light emission, photovoltaics, optical limiting, electro-optic modulation and laser-writing will be briefly discussed.

  10. A Platform for Functional Conductive Polymers

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hoffmann, Christian; Lind, Johan Ulrik; Hansen, Thomas Steen; Larsen, Niels Bent; Hvilsted, Søren

    2012-01-01

    Conductive polymers have been studied extensively during recent years. In order to broaden the application field of conductive polymers different methods have been tested and recently an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3) was developed(1, 2). The azide functional conductive polymer can be postpolymerization functionalized to introduce a large number of functionalities through click chemistry(3). Through selection of reaction conditions it is possible control the depth o...

  11. Nanostructured polymer membranes for proton conduction

    Science.gov (United States)

    Balsara, Nitash Pervez; Park, Moon Jeong

    2013-06-18

    Polymers having an improved ability to entrain water are characterized, in some embodiments, by unusual humidity-induced phase transitions. The described polymers (e.g., hydrophilically functionalized block copolymers) have a disordered state and one or more ordered states (e.g., a lamellar state, a gyroid state, etc.). In one aspect, the polymers are capable of undergoing a disorder-to-order transition while the polymer is exposed to an increasing temperature at a constant relative humidity. In some aspects the polymer includes a plurality of portions, wherein a first portion forms proton-conductive channels within the membrane and wherein the channels have a width of less than about 6 nm. The described polymers are capable of entraining and preserving water at high temperature and low humidity. Surprisingly, in some embodiments, the polymers are capable of entraining greater amounts of water with the increase of temperature. The polymers can be used in Polymer Electrolyte Membranes in fuel cells.

  12. Colloidal transparent conducting oxide nanocrystals: A new infrared plasmonic material

    Indian Academy of Sciences (India)

    Bharat Tandon; Aswathi Ashok; Angshuman Nag

    2015-06-01

    Thin films of transparent conducting oxides (TCO) are technologically important for applications as a visible light transparent electrode in a wide variety of optoelectronic devices. In the last few years, researchers started to explore novel size- and shape-dependent properties of TCO, where the crystallite size is ?10 nm. So far, the localized surface plasmon resonance (LSPR) properties of TCO nanocrystals (NCs) have been found to be the most interesting. TCOs like Sn-doped In2O3, Al-doped ZnO and In-doped CdO NCs, exhibit LSPR band in near- to mid-infrared region. LSPR from a TCO NC exhibits many intrinsic differences with that of a metal NC. Carrier density in a TCO NC can easily be tuned by controlling the dopant concentration, which allows the LSPR band to be tuned over a range of ?2000 nm (?0.62 eV) in the near- to mid-infrared region. This review discusses recent advances in the understanding of plasmonic properties of various TCO NCs and highlights the potential applications of such unique plasmonic properties.

  13. A Platform for Functional Conductive Polymers

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hoffmann, Christian

    Conductive polymers have been studied extensively during recent years. In order to broaden the application field of conductive polymers different methods have been tested and recently an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3) was developed(1, 2). The azide functional conductive polymer can be postpolymerization functionalized to introduce a large number of functionalities through click chemistry(3). Through selection of reaction conditions it is possible control the depth of the reaction into the polymer film to the upper surface or the entire film(4). Thus a conductive polymer can be prepared with a subsurface layer of highly conductive polymer where only the upper surface has been grafted with functional groups to ensure selectivity of the surface layer for e.g. interaction with specific biospecies. The conductive polymer can be patterned using selective etching, which enables preparation of e.g. interdigitated electrodes or other surface structures. The electrodes have been applied in controlled localized click reactions through ”electroclick” reactions(5). This enables preparation of both highly functional electrodes as well as gradient surfaces(6). The system is very versatile in all dimensions and structures and allows for preparation of conductive polymers with very specific properties. Recent results on a grafting from method to modify the surface properties will be presented.

  14. Nanostructured conductive polymers for advanced energy storage.

    Science.gov (United States)

    Shi, Ye; Peng, Lele; Ding, Yu; Zhao, Yu; Yu, Guihua

    2015-10-01

    Conductive polymers combine the attractive properties associated with conventional polymers and unique electronic properties of metals or semiconductors. Recently, nanostructured conductive polymers have aroused considerable research interest owing to their unique properties over their bulk counterparts, such as large surface areas and shortened pathways for charge/mass transport, which make them promising candidates for broad applications in energy conversion and storage, sensors, actuators, and biomedical devices. Numerous synthetic strategies have been developed to obtain various conductive polymer nanostructures, and high-performance devices based on these nanostructured conductive polymers have been realized. This Tutorial review describes the synthesis and characteristics of different conductive polymer nanostructures; presents the representative applications of nanostructured conductive polymers as active electrode materials for electrochemical capacitors and lithium-ion batteries and new perspectives of functional materials for next-generation high-energy batteries, meanwhile discusses the general design rules, advantages, and limitations of nanostructured conductive polymers in the energy storage field; and provides new insights into future directions. PMID:26119242

  15. Kinetics of radiation conductivity of polymer dielectrics

    International Nuclear Information System (INIS)

    Peculiarity of radiation conductivity kinetics of partially crystalline polymers (PTFE, PENP, PEVP, PP) at continuous electrons action (75 eV), dose rate D>10 Gy/s, within temperature range 100-373 K is existence of two and more maxima at certain irradiation temperatures. It is determined, that radiation conductivity in examined polymers have at less three kinetically distinguishable stages, and it does not approximating with simple power function going after the dispersion transport theory. Radiation conductivity of indicated polymers is determining by competition of jump and diffusion-controlled mechanism of charge carriers. It is stated, that radiation electric conductivity in the indicated objects is determining by molecular relaxation spectrum

  16. ELECTRICALLY CONDUCTIVE POLYMER-POLYMER COMPOSITES

    OpenAIRE

    Galvin, M; Wnek, G.

    1983-01-01

    Conductive composites have been prepared by polymerization of acelene in polyethylene films followed by iodine doping. The attainment of high conductivity (5-10 S/cm) at low (CH)x concentrations (?3 wt%) is explained with a simple percolation model.

  17. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik

    An azide substituted 3,4-ethylenedioxythiophene monomer is polymerised to yield a PEDOT like polymer with available azide groups (Figure 1). The azide groups enable post polymerization functionalization of the conducting polymer using a 1,3 dipolar cycloaddition reaction – also denoted “click chemistry”. This facilitates the addition of compounds that can otherwise not withstand the polymerization conditions. Several biological active molecules have been attached and tested on the films. Furthermore conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization with high spatial resolution. Interdigitated microelectrodes prepared from the azide-containing conducting polymer were selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. “Electro-click” on conducting polymer films shows the potential for being an important platform for biological devices and sensors.

  18. Hybrid conducting polymer-silver composites.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Bober, Patrycja; Trchová, Miroslava

    Ljubljana : Centre of Excellence PoliMaT, 2013 - (Žigon, M.; Rajšp, T.), s. 228-230 ISBN 978-961-269-992-5. [Austrian - Slovenian Polymer Meeting /3./ - ASPM 2013. Bled (SI), 03.04.2013-05.04.2013] R&D Projects: GA ?R GA202/09/1626; GA TA ?R TE01020022 Institutional support: RVO:61389013 Keywords : conducting polymers * polymer-silver composites * polyaniline Subject RIV: BK - Fluid Dynamics

  19. Electronically conducting polymers with silver grains

    Science.gov (United States)

    Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor); Hodko, Dolibor (Inventor)

    1999-01-01

    The present invention provides electronically conducting polymer films formed from photosensitive formulations of pyrrole and an electron acceptor that have been selectively exposed to UV light, laser light, or electron beams. The formulations may include photoinitiators, flexibilizers, solvents and the like. These solutions can be used in applications including printed circuit boards and through-hole plating and enable direct metallization processes on non-conducting substrates. After forming the conductive polymer patterns, a printed wiring board can be formed by sensitizing the polymer with palladium and electrolytically depositing copper.

  20. Gyroid nanoporous scaffold for conductive polymers

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Schulte, Lars; Zhang, Weimin; Vigild, Martin Etchells; Ndoni, Sokol; Chen, Jun

    2011-01-01

    Conductive nanoporous polymers with interconnected large surface area have been prepared by depositing polypyrrole onto nanocavity walls of nanoporous 1,2-polybutadiene films with gyroid morphology. Vapor phase polymerization of pyrrole was used to generate ultrathin films and prevent pore blocking. The resulting nanoporous polymers exhibited a promising electroactivity.

  1. A New Approach to the Synthesis of Conjugated Polymer: Nanocrystal Composites for Heterojunction Optoelectronics

    OpenAIRE

    Watt, A.; Thomsen, E; Meredith, P; Rubinsztein-Dunlop, H.

    2004-01-01

    We report a simple one pot process for the preparation of lead sulfide (PbS) nanocrystals in the conjugated polymer poly (2-methoxy-5-(2'ethyl-hexyloxy)-p-phenylene vinylene)(MEH-PPV), and we demonstrate electronic coupling between the two components.

  2. CONDUCTIVE POLYMERS AS ELECTRODE MATERIALS

    OpenAIRE

    Armand, M.

    1983-01-01

    Polyacetylene and its related polymers are amphoteric insertion compounds accomodating both cations and anions. This property make them ideal candidates for electrochemical energy storage. However the electrochemistry of these compounds is not fully clarified and the main remaining problems are evoked here.

  3. Conducting polymer based biomolecular electronic devices

    Indian Academy of Sciences (India)

    B D Malhotra; Rahul Singhal

    2003-08-01

    Biomolecular electronics is rapidly evolving from physics, chemistry, biology, electronics and information technology. Organic materials such as proteins, pigments and conducting polymers have been considered as alternatives for carrying out the functions that are presently being performed by semiconductor silicon. Conducting polymers such as polypyrroles, polythiophenes and polyanilines have been projected for applications for a wide range of biomolecular electronic devices such as optical, electronic, drug-delivery, memory and biosensing devices. Our group has been actively working towards the application of conducting polymers to Schottky diodes, metal–insulator–semiconductor (MIS) devices and biosensors for the past 10 years. This paper is a review of some of the results obtained at our laboratory in the area of conducting polymer biomolecular electronics.

  4. Nondestructive photolithography of conducting polymer structures

    Science.gov (United States)

    Chan, J. R.; Huang, X. Q.; Song, A. M.

    2006-01-01

    We have demonstrated a nondestructive method using ultraviolet (UV) photolithography to fabricate micrometer-sized conducting polymer structures. By coating a polymer film on patterned photoresist and then performing liftoff, UV exposure to the conducting polymer film was prevented throughout the lithography processes. We created features down to 1 ?m with high yield. Such complementary metal-oxide-semiconductor-compatible microfabrication can be applied generally to various organic films, and may allow the speed of organic electronics to be improved. Organic thin-film transistors (OTFTs) were fabricated using poly(3-hexylthiophene) as the active material, and typical OTFT characteristics were obtained.

  5. Phonon dispersion and thermal conductivity of nanocrystal superlattices using three-dimensional atomistic models

    Energy Technology Data Exchange (ETDEWEB)

    Zanjani, Mehdi B.; Lukes, Jennifer R., E-mail: jrlukes@seas.upenn.edu [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2014-04-14

    A computational study of thermal conductivity and phonon dispersion of gold nanocrystal superlattices is presented. Phonon dispersion curves, reported here for the first time from combined molecular dynamics and lattice dynamics calculations, show multiple phononic band gaps and consist of many more dispersion branches than simple atomic crystals. Fully atomistic three dimensional molecular dynamics calculations of thermal conductivity using the Green Kubo method are also performed for the first time on these materials. Thermal conductivity is observed to increase for increasing nanocrystal core size and decrease for increasing surface ligand density. Our calculations predict values in the range 0.1–1?W/m K that are consistent with reported experimental results.

  6. Processing of Polymer Nanocomposites Reinforced with Polysaccharide Nanocrystals

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2010-06-01

    Full Text Available Aqueous suspensions of polysaccharide (cellulose, chitin or starch nanocrystals can be prepared by acid hydrolysis of biomass. The main problem with their practical use is related to the homogeneous dispersion of these nanoparticles within a polymeric matrix. Water is the preferred processing medium. A new and interesting way for the processing of polysaccharide nanocrystals-based nanocomposites is their transformation into a co-continuous material through long chain surface chemical modification. It involves the surface chemical modification of the nanoparticles based on the use of grafting agents bearing a reactive end group and a long compatibilizing tail.

  7. Direct synthesis of PbS nanocrystals capped with 4-fluorothiophenol in semiconducting polymer

    International Nuclear Information System (INIS)

    We report on a simple chemical route to directly synthesize PbS nanocrystals capped with 4-fluorothiophenol in poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] semiconducting polymer. An intermediate composite, which has been characterized by X-ray photoelectron spectroscopy, has been synthesized to be used as nanocrystal precursor that contains both the metal and capping agent. Transmission electron microscopy images show that good quality nanoparticles with a mean size of ?5 nm are obtained with this method. Optical absorption measurements show that the absorption band of the polymer is extended as the PbS nanoparticles are included. Photoluminescence of the polymer becomes partially quenched as the concentration of the nanoparticles is increased in the composite.

  8. Tactile Sensors Based on Conductive Polymers

    OpenAIRE

    Macicior, Haritz; Sikora, Tomasz; Ochoteco, Estíbalitz; Castellanos Ramos, Julián; Navas González, Rafael; Vidal Verdú, Fernando

    2010-01-01

    This paper presents results from a selection of tactile sensors that have been designed and fabricated. These sensors are based on a common approach that consists in placing a sheet of piezoresistive material on the top of a set of electrodes. We use a thin film of conductive polymer as the piezoresistive mate¬rial. Specifically, a conductive water-based ink of this polymer is deposited by spin coating on a flexible plastic sheet, giving it a smooth, homogeneous and conducting thin film. The ...

  9. Liquid crystal-templated conducting organic polymers

    Science.gov (United States)

    Stupp, Samuel I.; Hulvat, James F.

    2004-01-20

    A method of preparing a conductive polymeric film, includes providing a liquid crystal phase comprising a plurality of hydrophobic cores, the phase on a substrate, introducing a hydrophobic component to the phase, the component a conductive polymer precursor, and applying an electric potential across the liquid crystal phase, the potential sufficient to polymerize the said precursor.

  10. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin; Christiansen, N.O.; Christensen, A.; Boisen, Anja

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity and strain sensitivity using two- and four-point measurement method. We have found that polyaniline has a negative gauge factor of K = -4.9, which makes it a candidate for piezoresistive read-out in polymer ba...

  11. Interpenetrating networks of two conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; West, Keld

    2005-01-01

    Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings, and because its reaction products can be removed efficiently after the formation of the composite. Several combinations of polymers are demonstrated, and the versatility of the proposed method allows extensions ...

  12. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede; Hvilsted, Søren; Larsen, Niels Bent

    2010-01-01

    An azide substituted 3,4-ethylenedioxythiophene monomer is polymerised to yield a PEDOT like polymer with available azide groups (Figure 1). The azide groups enable post polymerization functionalization of the conducting polymer using a 1,3 dipolar cycloaddition reaction – also denoted “click chemistry”. This facilitates the addition of compounds that can otherwise not withstand the polymerization conditions. Several biological active molecules have been attached and tested on the films. Further...

  13. Electrodeposited metals at conducting polymer electrodes

    International Nuclear Information System (INIS)

    Conducting polymers are electrochemically polymerized at platinum electrode substrates. The thickness, porosity and surface morphology of the resulting films are controlled by the charge passing during electropolymerization step and the synthesis conditions. The polymer films are modified by electrochemically depositing platinum particles. The technique of deposition depends on applying a programmed potential pulse at the polymer film from a solution containing platinum complex that resulted in the formation of platinum particles of controlled size and distribution. The effect of changing the size of platinum particles and polymer film thickness on the voltammetric behavior of the resulting hybrid material showed noticeable changes in the electro-catalytic current in acid medium. On the other hand, the electrochemical impedance spectroscopy experiments showed that diffusion and charge-transfer rate increased in the order: unmodified polymer films, thin polymer films containing small size/amount of platinum particles and relatively thick polymer films containing larger size/amount of platinum particles. The morphology of polymer films, size and distribution of platinum particles in the film were studied by scanning electron microscopy. The presence of platinum and its distribution over the film surface was confirmed from the X-ray dispersive analysis and surface mapping. The hybrid materials are good candidates for the application in devices for exchange of hydrogen ions

  14. Enhanced luminescence in metal/ (conducting polymer) nanocomposites

    International Nuclear Information System (INIS)

    Full text: We will discuss the ELINOR effect, the Enhanced Luminescence of INorganic and ORganic origin, which we recently identified in different (noble metal)/(conducting polymer) nanocomposites. The intense fluorescence of these composites can be pinned down to a synergic interaction between the plasmonic response of the nanostructured metallic aggregate and the electronic relaxation offered by the conducting polymer chains. We have shown that by careful control of the preparation conditions we can tune both the intensity and the wavelength of the emission maximum. We will discuss possible applications of these nanocomposites as molecular biomarkers (where we exploit the electrical affinity between conducting polymer chains and DNA molecules) and in the increase of efficiency of photovoltaic devices and solid state displays. Preliminary results of the ELINOR effect as a tool for rapid diagnosis of viral diseases and genetic polymorphisms will be also presented

  15. Conducting polymers: Synthesis and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The Conducting Polymer project funded by the AIM Materials Program is developing new methods for the synthesis of electronically conducting polymers and is evaluating new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1994 are electrochemical capacitors and membranes for gas separation. As an active material in electrochemical capacitors, conducting polymers have the potential of storing large amounts of electrical energy in low cost materials. Such devices are needed in electronics for power failure back-up and peak power, in power supplies for filtering, and in electric vehicles for peak power and load leveling. As a gas electrically adapt the membrane for specific gas combinations. Potential energy savings in the US. for this application are estimated at 1 to 3 quads/yr.

  16. Conducting polymers: Synthesis and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Lab., NM (United States)

    1997-04-01

    The Conducting Polymer project funded by the AIM Program has developed new methods for the synthesis of conducting polymers and evaluated new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1996 included two ongoing efforts on membranes for gas separation and on electrochemical capacitors and a third new application: electrochemical reactors (ECRs) based on polymeric electrolytes. As a gas separation membrane, conducting polymers offer high selectivity and the potential to chemically or electrically adapt the membrane for specific gas combinations. Potential energy savings in the US for this application are estimated at 1 to 3 quads/yr. As an active material in electrochemical capacitors, electronically conducting polymers have the potential of storing large amounts of electric energy in low cost materials. Potential energy savings estimated at 1 quad/yr would result from introduction of electrochemical capacitors as energy storage devices in power trains of electric and hybrid vehicles, once such vehicles reach 20% of the total transportation market in the US. In the chlor-alkali industry, electrochemical reactors based on polymer electrolyte membranes consume around 1 % of the total electric power in the US. A new activity, started in FY 1996, is devoted to energy efficient ECRs. In the case of the chlor-alkali industry, energy savings as high as 50% seem possible with the novel ECR technology demonstrated by the author in 1996.

  17. Mechanically stiff, electrically conductive composites of polymers and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Kucheyev, Sergei O.; Baumann, Theodore F.; Kuntz, Joshua D.; Satcher, Jr., Joe H.; Hamza, Alex V.

    2015-07-21

    Using SWNT-CA as scaffolds to fabricate stiff, highly conductive polymer (PDMS) composites. The SWNT-CA is immersing in a polymer resin to produce a SWNT-CA infiltrated with a polymer resin. The SWNT-CA infiltrated with a polymer resin is cured to produce the stiff and electrically conductive composite of carbon nanotube aerogel and polymer.

  18. /?SR of conducting and non-conducting polymers

    Science.gov (United States)

    Pratt, F. L.; Blundell, S. J.; Jestädt, Th; Lovett, B. W.; Husmann, A.; Marshall, I. M.; Hayes, W.; Monkman, A.; Watanabe, I.; Nagamine, K.; Martin, R. E.; Holmes, A. B.

    2000-08-01

    ?SR has been used to study a variety of polymers with very different electronic properties. In conducting polymers, the muon-generated radical states take the form of highly mobile polarons. Muon spin relaxation has been used to study the mobility of these polarons and to measure the temperature dependence of their intra-chain and inter-chain diffusion rates. It is found that the transport properties are strongly influenced by the librational ring modes of the phenylene rings in these polymers. In contrast, the muon-generated radical states in non-conducting polymers such as polybutadiene remain localised near the site of the muon. High field muon spin rotation, avoided level crossing resonance and longitudinal relaxation studies have been made, using the muon radical state as a probe of the dynamical properties of the polymer. Dramatic changes in the ?SR signals are seen on going through the glass-rubber transition, as various dynamical degrees of freedom become frozen out. Additional information about the stability of the muon radical states on the microsecond timescale has also been obtained using RF muon spin rotation techniques. Using time-delayed RF resonance of the diamagnetic state at the RIKEN-RAL muon facility, the transition rate between paramagnetic and diamagnetic states could be studied as a function of temperature.

  19. Conductive Polymer Functionalization by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hvilsted, SØren

    2008-01-01

    Click chemistry is used to obtain new conductive polymer films based on poly(3,4-ethylenedioxythiophene) (PEDOT) from a new azide functional monomer. Postpolymerization, 1,3-dipolar cycloadditions in DMF, using a catalyst system of CUS04 and sodium ascorbate, and different alkynes are performed to functionalize films of PEDOT-N3 and copolymers prepared from EDOT-N3 and 3,4-ethylenedioxythiophene (EDOT). This approach enables new functionalities on PEDOT that could otherwise not withstand the polymerization conditions. Reactions on the thin polymer films have been optimized using an alkynated fluorophore, with reaction times of '"'-'20 h. The applicability of the method is illustrated by coupling of two other alkynes: a short chain fluorocarbon and a MPEG 5000 to the conductive polymer; this alters the advancing water contact angle of the surface by +20° and -20°/-25°, respectively. The targeted chemical surface modifications have been verified by X-ray photoelectron spectroscopy analysis.

  20. Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Jordi Puiggalí

    2013-09-01

    Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

  1. SOLID STATE BATTERIES WITH CONDUCTING POLYMERS

    OpenAIRE

    Bénière, F.; Boils, D.; Cánepa, H.; Franco, J; Le Corre, A.; Louboutin, J.

    1983-01-01

    The conducting polymers like (CH)x are very interesting materials for electrodes in electrochemical cells. We have combined such electrodes with solid electrolytes to build "all solid-state" batteries. The first prototypes using a silver anode and a silver conducting electrolyte have been working satisfactorily since two years. The performances have been tested with many batteries to study the electrical properties as well as the thermodynamical parameters. A number of cycles of charge-discha...

  2. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity and strain sensitivity using two- and four-point measurement method. We have found that polyaniline has a negative gauge factor of K = -4.9, which makes it a candidate for piezoresistive read-out in polymer based MEMS-devices. (C) 2007 Elsevier B.V. All rights reserved.

  3. Ion-Conducting Organic/Inorganic Polymers

    Science.gov (United States)

    Kinder, James D.; Meador, Mary Ann B.

    2007-01-01

    Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solid-electrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices. The synthesis of a polymer of this type (see Figure 1) starts with a reaction between an epoxide-functionalized alkoxysilane and a diamine. The product of this reaction is polymerized by hydrolysis and condensation of the alkoxysilane group, producing a molecular network that contains both organic and inorganic (silica) links. The silica in the network contributes to the ionic conductivity and to the desired thermal and mechanical properties. Examples of other diamines that have been used in the reaction sequence of Figure 1 are shown in Figure 2. One can use any of these diamines or any combination of them in proportions chosen to impart desired properties to the finished product. Alternatively or in addition, one could similarly vary the functionality of the alkoxysilane to obtain desired properties. The variety of available alkoxysilanes and diamines thus affords flexibility to optimize the organic/inorganic polymer for a given application.

  4. Potential profile in a conducting polymer strip

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld

    2002-01-01

    Many conjugated polymers show an appreciable difference in volume between their oxidized and reduced forms. This property can be utilized in soft electrochemically driven actuators, "artificial muscles". Several geometries have been proposed for the conversion of the volume expansion into useful mechanical work. In a particularly simple geometry, the length change of polymer strips is exploited. The polymer strips are connected to the driving circuit at the end of the strip that is attached to the support of the device. The other end of the strip is connected to the load. The advantage of this set-up is simplicity and that the maximum force generated in the polymer can be transferred directly to the load. There is, however, an inherent problem in this design that will be examined in this paper. If the potential of the reduced state is below that for oxygen reduction, only a finite length of the free-standing film will be fully reduced. This is due to the reduction of oxygen at the surface of the polymer competing with the reduction of the polymer. For a long strip, the potential will therefore approach the reduction potential of oxygen. This will lower the efficiency of the artificial muscles and complicate measurements on free-standing films. A model of the potential profile in a free-standing strip is derived. It is found that the active length (the length with a given potential change) of the polymer will scale as square root (d sigma /i/sub d/). (d is the thickness, sigma the conductivity of the film, and i/sub d/ the diffusion limited current density for oxygen reduction). The active length is typically of the order of millimeters. The model is compared with measurements on a strip of polypyrrole doped with dodecylbenzene sulfonate

  5. Polarons and irradiation conductivity of polymer materials

    International Nuclear Information System (INIS)

    The theoretical description of irradiation conductivity of polymer materials has for a long time lagged behind the requirements for practical applications and the theory has not developed to the point of explaining the accumulated experimental data. The only model deserving discussion is the Rose-Fowler-Waisberg model, formulated more than 30 years ago. One of the main initial assumptions of this model is that the material is uniform and isotropic. Real polymer materials, however, have a complicated heterogeneous structure, which should significantly influence their electrophysical characteristics. For example, it has been established that amorphous a tactic polystyrene contains uniform blocks (domains) up to 3 nm in size with close-range order and high density and the space between the blocks contains much more loosely packed intercallations in which the short-range order of the molecular packing is destroyed. Loosely packed intercallations are also present in crystalline polymer materials. Evidence for the existence of bipolarons in irradiated polymer material is provided mainly by the results of analysis of experimental data on the EPR and optical absorption spectra and the spectra of thermally stimulated currents in irradiated polystyrene. The analysis performed in this work still does not prove convincingly that irradiated polystyrene contains bipolarons and that bipolarons play a significant role in the formation of the irradiation conduction current. This is because the characteristic features of bipolaron formation in polymer materials have not been adequately studied. However, existing theoretical ideas and comparison of these ideas with experimental data on EPR and optical-absorption spectra as well as other effects in irradiated polystyrene are already sufficient grounds for concluding that bipolarons cannot be neglected in the construction of physical and mathematical models of irradiation conduction current

  6. Actuator device utilizing a conductive polymer gel

    Science.gov (United States)

    Chinn, Douglas A.; Irvin, David J.

    2004-02-03

    A valve actuator based on a conductive polymer gel is disclosed. A nonconductive housing is provided having two separate chambers separated by a porous frit. The conductive polymer is held in one chamber and an electrolyte solution, used as a source of charged ions, is held in the second chamber. The ends of the housing a sealed with a flexible elastomer. The polymer gel is further provide with electrodes with which to apply an electrical potential across the gel in order to initiate an oxidation reaction which in turn drives anions across the porous frit and into the polymer gel, swelling the volume of the gel and simultaneously contracting the volume of the electrolyte solution. Because the two end chambers are sealed the flexible elastomer expands or contracts with the chamber volume change. By manipulating the potential across the gel the motion of the elastomer can be controlled to act as a "gate" to open or close a fluid channel and thereby control flow through that channel.

  7. Conducting polymer-hydrogels for medical electrode applications

    OpenAIRE

    Rylie A Green, Sungchul Baek, Laura A Poole-Warren and Penny J Martens

    2010-01-01

    Conducting polymers hold significant promise as electrode coatings; however, they are characterized by inherently poor mechanical properties. Blending or producing layered conducting polymers with other polymer forms, such as hydrogels, has been proposed as an approach to improving these properties. There are many challenges to producing hybrid polymers incorporating conducting polymers and hydrogels, including the fabrication of structures based on two such dissimilar materials and evaluatio...

  8. Ion conducting organic/inorganic hybrid polymers

    Science.gov (United States)

    Meador, Maryann B. (Inventor); Kinder, James D. (Inventor)

    2010-01-01

    This invention relates to a series of organic/inorganic hybrid polymers that are easy to fabricate into dimensionally stable films with good ion-conductivity over a wide range of temperatures for use in a variety of applications. The polymers are prepared by the reaction of amines, preferably diamines and mixtures thereof with monoamines with epoxy-functionalized alkoxysilanes. The products of the reaction are polymerized by hydrolysis of the alkoxysilane groups to produce an organic-containing silica network. Suitable functionality introduced into the amine and alkoxysilane groups produce solid polymeric membranes which conduct ions for use in fuel cells, high-performance solid state batteries, chemical sensors, electrochemical capacitors, electro-chromic windows or displays, analog memory devices and the like.

  9. The Organic Chemistry of Conducting Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, Laren Malcolm [Georgia Institute of Technology

    2014-12-01

    For the last several years, we have examined the fundamental principles of conduction in one-dimensional systems, i.e., molecular “wires”. It is, of course, widely recognized that such systems, as components of electronically conductive materials, function in a two- and three-dimensional milieu. Thus interchain hopping and grain-boundary resistivity are limiting conductivity factors in highly conductive materials, and overall conductivity is a function of through-chain and boundary hopping. We have given considerable attention to the basic principles underlying charge transport (the “rules of the game”) in two-dimensional systems by using model systems which allow direct observation of such processes, including the examination of tunneling and hopping as components of charge transfer. In related work, we have spent considerable effort on the chemistry of conjugated heteropolymers, most especially polythiophens, with the aim of using these most efficient of readily available electroactive polymers in photovoltaic devices.

  10. Conductive Polymer Functionalization by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hvilsted, Søren; Hansen, Thomas Steen; Larsen, Niels Bent

    2008-01-01

    Click chemistry is used to obtain new conductive polymer films based on poly(3,4-ethylenedioxythiophene) (PEDOT) from a new azide functional monomer. Postpolymerization, 1,3-dipolar cycloadditions in DMF, using a catalyst system of CUS04 and sodium ascorbate, and different alkynes are performed to functionalize films of PEDOT-N3 and copolymers prepared from EDOT-N3 and 3,4-ethylenedioxythiophene (EDOT). This approach enables new functionalities on PEDOT that could otherwise not withstand the pol...

  11. Electrochromic window with lithium conductive polymer electrolyte

    OpenAIRE

    Baudry, Paul; Aegerter, Michel A.; Deroo, Daniel; Valla, Bruno

    1990-01-01

    An electrochromic window was built using WO3 as the electrochromic material and V2O5 as the counter-electrode. Both were deposited onto ITO coated glass panes by vacuum evaporation and were amorphous to X-ray diffraction. The electrolyte was a lithium conducting polymer constituted by a Poly (ethylene oxide) - lithium salt complex. The electrochemical characterization of electrodes was realized by cyclic voltammetry, coulometric titration, and impedance spectroscopy, which allowd the determin...

  12. Gas Sensors Based on Conducting Polymers

    OpenAIRE

    Gaoquan Shi; Hua Bai

    2007-01-01

    The gas sensors fabricated by using conducting polymers such as polyaniline (PAni), polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.

  13. Radiation-induced electric conductivity of polymers

    International Nuclear Information System (INIS)

    Radiation-induced electric conductivity of polystyrene, polyethylene and polypropylene, excited by pulses of accelerated (60 keV) electrons of 1 ms to 10 s duration with a change in electric field to prebreak down voltage (? 2x108 V/m) in vacuum at room temperature was studied. Specific features of recombination effects at increased dose rate were considered. General theoretic problems of radiation-induced electric conductivity of the polymers, especially of heminal mechanism realized in polypropylene, and for pulses of radiation shorter than 0.1 s in polyethylene, as well, are discussed

  14. Electrochemical Analysis of Conducting Polymer Thin Films

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2010-04-01

    Full Text Available Polyelectrolyte multilayers built via the layer-by-layer (LbL method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene (PPV, in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values.

  15. Conducting Polymers and Their Hybrids as Organic Thermoelectric Materials

    Science.gov (United States)

    Toshima, Naoki; Ichikawa, Shoko

    2015-01-01

    Conducting polymers have received much attention recently as organic thermoelectric materials, because of such advantages as plentiful resources, easy synthesis, easy processing, low cost, low thermal conductivity, and easy fabrication of flexible, light, and printable devices with large area. Many reports on organic thermoelectric materials have recently been published. We have studied conducting polymers as organic thermoelectric materials since 1999. During these investigations, we found that the thermal conductivity of conducting polymers did not increase even though electrical conductivity increased; this was a major advantage of conducting polymers as organic thermoelectric materials. We also observed that molecular alignment was one of the most important factors for improvement of the thermoelectric performance of conducting polymers. Stretching of conducting polymers or their precursors was one of the most common techniques used to achieve good molecular alignment. Recently, alignment of the clusters of conducting polymers by treatment with solvents has been proposed as a means of achieving high electrical conductivity. Hybridization of conducting polymers with inorganic nanoparticles has also been found to improve thermoelectric performance. Here we present a brief history and discuss recent progress of research on conducting polymers as organic thermoelectric materials, and describe the techniques used to improve thermoelectric performance by treatment of conducting polymers with solvents and hybridization of conducting polymers with Bi2Te3 and gold nanoparticles.

  16. Structural investigations and processing of electronically and protonically conducting polymers

    OpenAIRE

    Vilkman, Marja

    2010-01-01

    Various conducting polymers form a special class of materials with the potential for many applications in organic electronics and functional materials. These polymers can be electronically conducting or semiconducting due to a conjugated polymer backbone, or alternatively possess conductivity due to mobile protons or other ions. This thesis discusses such conducting polymers and shows ways how they can be processed by printing and how the nanostructure allows controlling their electrical prop...

  17. HREELS and Auger studies of conducting polymers

    Science.gov (United States)

    Jennings, W. D.; Chottiner, G. S.; Natarajan, C.; Melo, A. V.; Hoffman, R. W.; O'Grady, W. E.; Lundström, I.; Salaneck, W. R.

    1985-04-01

    High Resolution Electron Energy Loss Spectroscopy (HREELS) and Auger Spectroscopy have been used to examine the surface of conducting polymer samples. The samples were 100 nm thick films of polypyrrole doped with either BF 4 or ClO 4 negative ions. The films were made in Sweden and shipped to the USA for study. HREELS spectra could be obtaineed without difficulty in the samples' "as-is" condition. These spectra showed broad bands corresponding to known polypyrrole vibrational modes. Exposure of the polymer to oxygen had no effect, but water could be adsorbed on the samples at 130 K. In addition to vibrational excitations, broader electronic transitions were also identified. Auger studies were performed in an effort to characterize the surface. These studies indicate that considerable non-stoichiometry exists in the surface region. There were, as expected, problems due to questionable sample cleanliness, sample charging, and electron beam damage.

  18. Polymer composite material structures comprising carbon based conductive loads

    OpenAIRE

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Lucasz; Daussin, Raphaël; Saib, Aimad

    2006-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 to 6 wt% carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loads. Th...

  19. Polymer composite material structures comprising carbon based conductive loads

    OpenAIRE

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Luikasz; Daussin, Raphaël; Saib, Aimad; Baudouin, Anne-Christine; Laloyaux, Xavier

    2007-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 wt % to 6 wt % carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loa...

  20. Electrochemical characterization of aminated acrylic conducting polymer

    Science.gov (United States)

    Rashid, Norma Mohammad; Heng, Lee Yook; Ling, Tan Ling

    2015-09-01

    New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25?m particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

  1. Smart Surface Chemistries of Conducting Polymers

    DEFF Research Database (Denmark)

    Lind, Johan Ulrik

    2012-01-01

    In this thesis we investigate post-polymerization covalent modifications of poly(3,4-dioxythiophene (PEDOT)-type conducting polymers. The aim of the modifications is to gain specific control of the interaction between the material and living mammalian cells. The use of “click-chemistry” to modify an azide-modified PEDOT, poly(3,4-(1-azidomethylethylene)-dioxythiophene) (PEDOT-N3), is studied in detail, and found to be a valuable approach. This is concluded, as we are able to obtain delicate cont...

  2. Biomimetic electrochemistry from conducting polymers. A review

    International Nuclear Information System (INIS)

    Highlights: ? Composition and properties of conducting polymers change during reactions. ? These properties are being exploited to develop biomimetic reactive and soft devices. ? The state of the art for artificial muscles sensing working conditions was reviewed. ? Smart membranes, drug delivery devices and nervous interfaces were also reviewed. - Abstract: Films of conducting polymers in the presence of electrolytes can be oxidized or reduced by the flow of anodic or cathodic currents. Ions and solvent are exchanged during a reaction for charge and osmotic pressure balance. A reactive conducting polymer contains ions and solvent. Such variation of composition during a reaction is reminiscent of the biological processes in cells. Along changes to the composition of the material during a reaction, there are also changes to other properties, including: volume (electrochemomechanical), colour (electrochromic), stored charge (electrical storage), porosity or permselectivity (electroporosity), stored chemicals, wettability and so on. Most of those properties mimic similar property changes in organs during their functioning. These properties are being exploited to develop biomimetic reactive and soft devices: artificial muscles and polymeric actuators; supercapacitors and all organic batteries; smart membranes; electron-ion transducers; nervous interfaces and artificial synapses, or drug delivery devices. In this review we focus on the state of the art for artificial muscles, smart membranes and electron-ion transducers. The reactive nature of those devices provide them with a unique advantage related to the present days technologies: any changes in the surrounding physical or chemical variable acting on the electrochemical reaction rate will be sensed by the device while working. Working under constant current (driving signal), the evolution of the device potential or the evolution of the consumed electrical energy (sensing signals) senses and quantifies the variable increment. Driving and sensing signals are present, simultaneously, in the same two connecting wires. It is possible to prepare electrochemical devices based on conducting polymers in which there are several kinds of different sensors and one actuator embedded in one device. Examples of the tools and products, start-up companies, increasing evolution of scientific literature and patents are also presented. Scientific and technological challenges are also considered.

  3. Conductive inks for metalization in integrated polymer microsystems

    Science.gov (United States)

    Davidson, James Courtney (Livermore, CA); Krulevitch, Peter A. (Pleasanton, CA); Maghribi, Mariam N. (Livermore, CA); Benett, William J. (Livermore, CA); Hamilton, Julie K. (Tracy, CA); Tovar, Armando R. (San Antonio, TX)

    2006-02-28

    A system of metalization in an integrated polymer microsystem. A flexible polymer substrate is provided and conductive ink is applied to the substrate. In one embodiment the flexible polymer substrate is silicone. In another embodiment the flexible polymer substrate comprises poly(dimethylsiloxane).

  4. Light-induced instability in current conduction of aluminum nitride thin films embedded with Al nanocrystals

    International Nuclear Information System (INIS)

    Al nanocrystals (nc-Al) embedded in AlN thin films have been synthesized by rf magnetron sputtering. The influence of ultraviolet (UV) illumination on electrical characteristics of the nc-Al/AlN thin film system has been investigated. It is shown that the UV illumination could lead to a random change in the conductance of the thin film system. The change in the conductance is attributed to the charge trapping and detrapping in the nc-Al due to the UV illumination

  5. Electrical Properties of Conductive Ge Nanocrystal Thin Films Fabricated by Low Temperature In-situ Growth

    OpenAIRE

    Zhang, B.; Y. Yao; Patterson, R.; Shrestha, S; Green, M. A.; Conibeer, G.

    2011-01-01

    Thin films composed of Ge nanocrystals embedded in amorphous SiO2 matrix (Ge-NCs TFs) were prepared using a low temperature in-situ growth method. Unexpected high p-type conductivity was observed in the intrinsic Ge-NCs TFs. Unintentional doping from shallow dopants was excluded as a candidate mechanism of hole generation. Instead, the p-type characteristic was attributed to surface state induced hole accumulation in NCs, and the hole conduction was found to be a thermally a...

  6. Catalytic synthesis of metal crystals using conductive polymers

    Science.gov (United States)

    Wang, Hsing-Lin (Los Alamos, NM); Li, Wenguang (Los Alamos, NM)

    2008-01-15

    A method of forming metal nanoparticles using a polymer colloid that includes at least one conductive polymer and at least one polyelectrolyte. Metal ions are reduced in water by the conductive polymer to produce the nanoparticles, which may be then incorporated in the colloidal structure to form a colloid composite. The method can also be used to separate selected metal ions from aqueous solutions.

  7. Multi-stimulus-responsive shape-memory polymer nanocomposite network cross-linked by cellulose nanocrystals.

    Science.gov (United States)

    Liu, Ye; Li, Ying; Yang, Guang; Zheng, Xiaotong; Zhou, Shaobing

    2015-02-25

    In this study, we developed a thermoresponsive and water-responsive shape-memory polymer nanocomposite network by chemically cross-linking cellulose nanocrystals (CNCs) with polycaprolactone (PCL) and polyethylene glycol (PEG). The nanocomposite network was fully characterized, including the microstructure, cross-link density, water contact angle, water uptake, crystallinity, thermal properties, and static and dynamic mechanical properties. We found that the PEG[60]-PCL[40]-CNC[10] nanocomposite exhibited excellent thermo-induced and water-induced shape-memory effects in water at 37 °C (close to body temperature), and the introduction of CNC clearly improved the mechanical properties of the mixture of both PEG and PCL polymers with low molecular weights. In addition, Alamar blue assays based on osteoblasts indicated that the nanocomposites possessed good cytocompatibility. Therefore, this thermoresponsive and water-responsive shape-memory nanocomposite could be potentially developed into a new smart biomaterial. PMID:25647407

  8. Characterizations of proton conducting polymer electrolytes for electrochemical capacitors

    International Nuclear Information System (INIS)

    Solid polymer electrolytes containing phosphotungstic acid (PWA) and/or silicotungstic acid (SiWA) in polyvinyl alcohol (PVA) were investigated for their proton conductivities. Enhanced conductivity was obtained when mixing PWA and SiWA at equal ratio. This polymer electrolyte was found viable for electrochemical capacitors. Thermal and structural analyses were conducted with DSC, XRD, and FTIR. The polymer electrolyte exhibited a different structure and different thermal properties from its respective components. The polymer electrolyte retained its original Keggin structure but contained crystallized protonated water in the form of H5O2+. The protonated water may contribute to the proton conductivity of the polymer electrolyte.

  9. Conducting Polymer Nanostructures: Template Synthesis and Applications in Energy Storage

    OpenAIRE

    Lijia Pan; Hao Qiu; Chunmeng Dou; Yun Li; Lin Pu; Jianbin Xu; Yi Shi

    2010-01-01

    Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template met...

  10. Conducting Polymer Nanostructures: Template Synthesis and Applications in Energy Storage

    Directory of Open Access Journals (Sweden)

    Lijia Pan

    2010-07-01

    Full Text Available Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed.

  11. Hybrid solar cells based on colloidal nanocrystals and conjugated polymers

    International Nuclear Information System (INIS)

    In this study, monodispersed colloidal titanium dioxide (TiO2) was synthesized and applied with poly(3-octylthiophene-2,5-diyl) (P3OT), phenyl-C61-butyric acid methyl ester (PCBM), poly(3,4-ethylene dioxythiophene) (PEDOT), and poly(styrenesulfonate (PSS) to fabricate an aluminum/calcium/P3OT:PCBM:TiO2/PEDOT:PSS/indium tin oxide hybrid solar cell using spin coating and evaporation deposition. The effects of the TiO2 content and annealing temperature on cell performances were investigated. The results showed that optimization of the TiO2 content (15 wt.%) and annealing temperature (150 °C) effectively enhanced the performance of the hybrid solar cells. The PCBM and TiO2 absorbed more light photons in the P3OT:PCBM:TiO2 active layer. The charge transfer in the P3OT:PCBM:TiO2 active layer was more efficient, increasing the amount of photoluminescence quenching. The increased active layer surface roughness reduced the charge-transport distance and enhanced the internal light scattering and light absorption. The best values for the open circuit voltage, short-circuit current density, fill factor, and efficiency for the prepared hybrid solar cell were 0.61 V, 9.50 mA/cm2, 34.46%, and 2.09%, respectively. - Highlights: • Solar cell based on titania and conjugated polymer was fabricated. • Optimal titania content and annealing temperature were investigated. • Solar cell with 2.09% efficiency was obtained

  12. Current Trends in Sensors Based on Conducting Polymer Nanomaterials

    OpenAIRE

    Hyeonseok Yoon

    2013-01-01

    Conducting polymers represent an important class of functional organic materials for next-generation electronic and optical devices. Advances in nanotechnology allow for the fabrication of various conducting polymer nanomaterials through synthesis methods such as solid-phase template synthesis, molecular template synthesis, and template-free synthesis. Nanostructured conducting polymers featuring high surface area, small dimensions, and unique physical properties have been widely used to buil...

  13. Conducting polymers a new era in electrochemistry

    CERN Document Server

    Inzelt, György

    2012-01-01

    The 2nd edition of this successful book is thoroughy updated to include additional polymers such as polyindole and polyazines, composites of polymers with carbon nanotubes, metals, and metal oxides, as well as bending-beam techniques for characterization.

  14. Solar cells based on colloidal nanocrystals

    CERN Document Server

    Borchert, Holger

    2014-01-01

    This book presents a new system of solar cells. Colloidal nanocrystals possess many physical and chemical properties which can be manipulated by advanced control over structural features like the particle size. One application field is photovoltaics where colloidal semiconductor nanocrystals are explored as components of photo-active layers which can be produced from liquid media, often in combination with conductive polymers. The further development of this interdisciplinary field of research requires a deep understanding of the physics and chemistry of colloidal nanocrystals, conducting poly

  15. Proton Conducting Polymer Electrolyte Based on Pva-Pan

    Science.gov (United States)

    Devi, S. Siva; Selvasekarapandian, S.; Rajeswari, N.; Genova, F. Kingslin Mary; Karthikeyan, S.; Raja, C. Sanjeevi

    2013-07-01

    Proton conducting polymer electrolytes based on blend polymer using Poly Vinyl Alcohol (PVA) and Poly Acrylo Nitrile (PAN) doped with ammonium nitrate have been prepared by solution casting method. The highest conductivity at room temperature (305K) has been found to be 1.8×10-3 S cm-1 for 15 mole % NH4NO3 doped PVA-PAN system. X ray Diffraction pattern of the doped and the undoped blend polymer electrolyte confirms the amorphous nature of blend polymer, when salt is added. The complex formation between the blend polymer and the salt has been confirmed by Fourier transform infrared spectroscopy.

  16. Mechanism of actuation in conducting polymers: Osmotic expansion

    DEFF Research Database (Denmark)

    Bay, Lasse; Jacobsen, Torben; West, Keld; Skaarup, Steen

    2001-01-01

    Conducting polymers expand or contract when their redox state is changed. This expansion/contraction effect can be separated in an intrinsic part because of changes of the polymer backbone on reduction/oxidation and a part depending on the surrounding electrolyte phase, because of osmotic expansion of the polymer phase. The osmotic effect causes solvent molecules to move into the polymer in a number far in excess of those bound strongly in the solvation shell of the mobile ion, resulting in larg...

  17. Mesoscopic modelling of charge evolution in conducting polymers

    OpenAIRE

    Ramos, Marta M. D.; Stoneham, A.M.

    2000-01-01

    We address here some of the issues relating to conducting polymer based devices. We examine the effects of polymer disorder on charge injection, transport, trapping and recombination in light-emitting diodes (LEDs) using a mesoscopic model which includes specific realizations of the electroluminescent polymer network. A key point of this model is to consider both the intermolecular and the interdomain charge carrier transport which are strongly influenced by structural polymer disorder. Simul...

  18. Applications of conducting polymers: robotic fins and other devices

    Science.gov (United States)

    Tangorra, James L.; Anquetil, Patrick A.; Weideman, Nathan S.; Fofonoff, Timothy; Hunter, Ian W.

    2007-04-01

    Conducting polymers are becoming viable engineering materials and are gradually being integrated into a wide range of devices. Parallel efforts conducted to characterize their electromechanical behavior, understand the factors that affect actuation performance, mechanically process films, and address the engineering obstacles that must be overcome to generate the forces and displacements required in real-world applications have made it possible to begin using conducting polymers in devices that cannot be made optimal using traditional actuators and materials. The use of conducting polymers has allowed us to take better advantage of biological architectures for robotic applications and has enabled us to pursue the development of novel sensors, motors, and medical diagnostic technologies. This paper uses the application of conducting polymer actuators to a biorobotic fin for unmanned undersea vehicles (UUVs) as a vehicle for discussing the efforts in our laboratory to develop conducting polymers into a suite of useful actuators and engineering components.

  19. Conducting polymer supported bilayer lipid membrane reconstituted with alamethicin

    International Nuclear Information System (INIS)

    Ionic electroactive polymers and bioderived materials have been independently demonstrated as actuators, sensors and energy harvesting devices. In an electroactive polymer, the applied electric field between the cathode and anode drives ion transport between the electrodes, impregnated electrolyte and the bulk of the polymer to generate force and displacement. Similarly, in a bioderived material an input stimulus (electrical, chemoelectrical or chemical) applied across the protein in a bilayer lipid membrane (BLM) displaces ions across the membrane barrier and enables sensing and actuation functions. This paper presents a novel architecture for a device that integrates the ionic function of an electroactive polymer and a bioderived material into a thin-film laminated device combining their unique advantages. A conducting polymer (PPy(DBS)) is used as the electroactive polymer and alamethicin-bound bilayer lipid membrane is used as the bioderived material in the thin-film laminated device. Owing to the configuration of the laminated device, the protein regulates the ionic concentration in the conducting polymer and regulates the electrochemical doping/undoping process in the polymer. By electrically connecting the conducting polymer across its thickness, this arrangement provides a mechanism external to the polymer besides electrical field that can control the electrical, mechanical and/or optical properties of the conducting polymer. This paper also presents the fabrication and characterization of the integrated ionic device and presents a template for the development of a novel category of electroactive ionic devices

  20. Proton-conducting electrolyte membranes based on aromatic condensation polymers

    International Nuclear Information System (INIS)

    The results of investigations in the field of development and applications of proton-conducting electrolyte membranes based on aromatic condensation polymers are analysed and summarised. Primary attention is paid to the properties of the starting polymers, such as the thermal stability, water uptake and proton conductivity. General approaches to the preparation of aromatic condensation polymers with high proton conductivity are considered, including sulfonation, synthesis from monomers containing sulfonic acid groups, incorporation of alkylsulfonated substituents and formation of acid-basic polymer complexes. The bibliography includes 115 references.

  1. Potential profile in a conducting polymer strip

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld; Vlachopoulos, Nikolaos; Skaarup, Steen

    2002-01-01

    Many conjugated polymers show an appreciable difference in volume between their oxidized and reduced forms. This property can be utilized in soft electrochemically driven actuators, "artificial muscles". Several geometries have been proposed for the conversion of the volume expansion into useful mechanical work. In a particularly simple geometry, the length change of polymer strips is exploited. The polymer strips are connected to the driving circuit at the end of the strip that is attached to t...

  2. Nobel Prize 2000: from conducting polymers to molecular electronics

    International Nuclear Information System (INIS)

    In this paper the development of conducting organic polymers is reviewed. Poly(3-alkylthiophenes) with regioregularity exceeding 99% are especially interesting because if used as a thin semiconducting layer in the field effect transistor (FET) configuration they become superconducting at 2.35 K. This is the first example of the superconductivity of an organic polymer. Fields of use of conducting polymers are reviewed, too

  3. Solid Polymer Lithium-Ion Conducting Electrolytes for Structural Batteries

    OpenAIRE

    Willgert, Markus

    2014-01-01

    This work comprises the manufacture and characterization of solid polymer lithium ion conducting electrolytes for structural batteries. In the study, polymer films are produced in situ via a rapid versatile UV irradiation polymerization route, in which ethylene oxide methacrylates are polymerized into thermoset networks. In the first part of the study, the simplicity and efficiency of this manufacturing route is emphasized. Polymer electrolytes are pro-duced with an ionic conductivity ranging...

  4. Electrochemical Impedance Spectroscopy of Conductive Polymer Coatings

    Science.gov (United States)

    Calle, Luz Marina; MacDowell, Louis G.

    1996-01-01

    Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion protection performance of twenty nine proprietary conductive polymer coatings for cold rolled steel under immersion in 3.55 percent NaCl. Corrosion potential as well as Bode plots of the data were obtained for each coating after one hour immersion, All coatings, with the exception of one, have a corrosion potential that is higher in the positive direction than the corrosion potential of bare steel under the same conditions. Group A consisted of twenty one coatings with Bode plots indicative of the capacitive behavior characteristic of barrier coatings. An equivalent circuit consisting of a capacitor in series with a resistor simulated the experimental EIS data for these coatings very well. Group B consisted of eight coatings that exhibited EIS spectra showing an inflection point which indicates that two time constants are present. This may be caused by an electrochemical process taking place which could be indicitive of coating failing. These coatings have a lower impedance that those in Group A.

  5. Direct measurement of the microscale conductivity of conjugated polymer monolayers

    DEFF Research Database (Denmark)

    BØggild, Peter; Grey, Francois

    2000-01-01

    The in-plane conductivity of conjugated polymer monolayers is mapped here for the first time on the microscale using a novel scanning micro four-point probe (see Figure). The probe allows the source, drain, and voltage electrodes to be positioned within the same domain and the mapping results demonstrate how microscopic ordering in the polymer domains controls the conductivity.

  6. Spatially Selective Functionalization of Conducting Polymers by "Electroclick" Chemistry

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Daugaard, Anders Egede; Hvilsted, Søren; Larsen, Niels Bent

    2009-01-01

    Conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization by "click chemistry" with high spatial resolution. Interdigitated microelectrodes prepared from an azide-containing conducting polymer are selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials.

  7. Nanostructured conducting polymer hydrogels for energy storage applications

    Science.gov (United States)

    Shi, Ye; Peng, Lele; Yu, Guihua

    2015-07-01

    Conducting polymer hydrogels are emerging as a promising class of polymeric materials for various technological applications, especially for energy storage devices due to their unique combination of advantageous features of conventional polymers and organic conductors. To overcome the drawbacks of conventional synthesis, new synthetic routes in which acid molecules are adopted as both crosslinkers and dopants have been developed for conducting polymer hydrogels with unique 3D hierarchical porous nanostructures, resulting in high electrical conductivity, large surface area, structural tunability and hierarchical porosity for rapid mass/charge transport. The newly developed conducting polymer hydrogels exhibit high performance when applied as active electrode materials for electrochemical capacitors or as functional binder materials for high-energy lithium-ion batteries. This feature article summarizes the synthesis of conducting polymer hydrogels, presents their applications in energy storage, and discusses further opportunities and challenges.

  8. Electromagnetic properties of conducting polymers encapsulated in an insulating matrix

    International Nuclear Information System (INIS)

    The aim of this work is to study the electronic properties of conducting polymers encapsulated in zeolite. We studied two kinds of polymers: intrinsic conducting polymers (poly-pyrrole) and pyrolyzed polymers (polyacrylonitrile and poly-furfuryl alcohol). These systems were characterized by electron paramagnetic resonance and microwave conductivity measurements. In the first part, we present the preparation and the characterization of encapsulated poly-pyrrole. Conductivity measurements show that the encapsulated material is insulating, certainly because a strong interaction with the zeolite traps the charge carriers. In the second part, we focus on pyrolyzed encapsulated polyacrylonitrile. This system has a metal-like susceptibility at room temperature and a relatively high microwave conductivity. These results demonstrate the formation during the pyrolysis of extended aromatic clusters. Finally, we study pyrolyzed encapsulated poly-furfuryl alcohol. We show that the only effect of the pyrolysis is to fragment the polymers. We also discuss the spin relaxation and the EPR line broadening. (author)

  9. Self-assembled hybrid materials based on conjugated polymers and semiconductors nano-crystals for plastic solar cells

    International Nuclear Information System (INIS)

    This work is devoted to the elaboration of self-assembled hybrid materials based on poly(3- hexyl-thiophene) and CdSe nano-crystals for photovoltaic applications. For that, complementary molecular recognition units were introduced as side chain groups on the polymer and at the nano-crystals' surface. Diamino-pyrimidine groups were introduced by post-functionalization of a precursor copolymer, namely poly(3-hexyl-thiophene-co-3- bromo-hexyl-thiophene) whereas thymine groups were introduced at the nano-crystals' surface by a ligand exchange reaction with 1-(6-mercapto-hexyl)thymine. However, due to their different solubility, the mixing of the two components by solution processes is difficult. A 'one-pot' procedure was developed, but this method led to insoluble aggregates without control of the hybrid composition. To overcome the solubility problem, the layer-by-layer method was used to prepare the films. This method allows a precise control of the deposition process. Experimental parameters were tested in order to evaluate their impact on the resulting film. The films morphology was investigated by microscopy and X-Ray diffraction techniques. These analyses reveal an interpenetrated structure of nano-crystals within the polymer matrix rather than a multilayered structure. Electrochemical and spectro electrochemical studies were performed on the hybrid material deposited by the LBL process. Finally the materials were tested in a solar cell configuration and the I=f(V) curves reveals a clear photovoltaic behaviour. (author)

  10. Anion-conducting polymer, composition, and membrane

    Science.gov (United States)

    Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

    2011-11-22

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  11. Proton-Conducting Magnetic Coordination Polymers.

    Science.gov (United States)

    Biswas, Soumava; Jena, Himanshu Sekhar; Sanda, Suresh; Konar, Sanjit

    2015-09-21

    Three isostructural lanthanide-based two- dimensional coordination polymers (CPs) {[Ln2 (L)3 (H2 O)2 ]n ?2n?CH3 OH)?2n?H2 O} (Ln=Gd(3+) (1), Tb(3+) (2), Dy(3+) (3); H2 L=cyclobutane-1,1-dicarboxylic acid) were synthesized by using a low molecular weight dicarboxylate ligand and characterized. Single-crystal structure analysis showed that in complexes 1-3 lanthanide centers are connected by ?3 -bridging cyclobutanedicarboxylate ligands along the c axis to form a rod-shaped infinite 1D coordination chain, which is further linked with nearby chains by ?4 -connected cyclobutanedicarboxylate ligands to form 2D CPs in the bc plane. Viewing the packing of the complexes down the b axis reveals that the lattice methanol molecules are located in the interlayer space between the adjacent 2D layers and form H-bonds with lattice and coordinated water molecules to form 1D chains. Magnetic properties of complexes 1-3 were thoroughly investigated. Complex 1 exhibits dominant ferromagnetic interaction between two nearby gadolinium centers and also acts as a cryogenic magnetic refrigerant having a significant magnetic entropy change of -?Sm =32.8?J?kg(-1) ?K(-1) for ?H=7?T at 4?K (calculated from isothermal magnetization data). Complex 3 shows slow relaxation of magnetization below 10?K. Impedance analysis revealed that the complexes show humidity-dependent proton conductivity (?=1.5×10(-5) ?S?cm(-1) for 1, ?=2.07×10(-4) ?S?cm(-1) for 2, and ?=1.1×10(-3) ?S?cm(-1) for 3) at elevated temperature (>75?°C). They retain the conductivity for up to 10?h at high temperature and high humidity. Furthermore, the proton conductivity results were correlated with the number of water molecules from the water-vapor adsorption measurements. Water-vapor adsorption studies showed hysteretic and two-step water vapor adsorption (182000??L?g(-1) for 1, 184000??L?g(-1) for 2, and 1874000??L?g(-1) for 3) in the experimental pressure range. Simulation of water-vapor adsorption by the Monte Carlo method (for 1) confirmed the high density of adsorbed water molecules, preferentially in the interlayer space between the 2D layers. PMID:26274020

  12. Electrical properties of conductive Ge nanocrystal thin films fabricated by low temperature in situ growth.

    Science.gov (United States)

    Zhang, B; Yao, Y; Patterson, R; Shrestha, S; Green, M A; Conibeer, G

    2011-03-25

    Thin films composed of Ge nanocrystals embedded in an amorphous SiO(2) matrix (Ge-NC TFs) were prepared using a low temperature in situ growth method. Unexpected high p-type conductivity was observed in the intrinsic Ge-NC TFs. Unintentional doping from shallow dopants was excluded as a candidate mechanism of hole generation. Instead, the p-type characteristic was attributed to surface state induced hole accumulation in NCs, and the hole conduction was found to be a thermally activated process involving charge hopping from one NC to its nearest neighbor. Theoretical analysis has shown that the density of surface states in Ge-NCs is sufficient to induce adequate holes for measured conductivity. The film conductivity can be improved significantly by post-growth rapid thermal annealing and this effect is explained by a simple thermodynamic model. The impact of impurities on the conduction properties was also studied. Neither compensation nor enhancement in conduction was observed in the Sb- and Ga-doped Ge-NC TFs, respectively. This could be attributed to the fact that these impurities are no longer shallow dopants in NCs and are much less likely to be effectively activated. Finally, the photovoltaic effect of heterojunction diodes employing such Ge-NC TFs was characterized in order to demonstrate its functionality in device implementation. PMID:21325714

  13. Nuclear alkylated pyridine aldehyde polymers and conductive compositions thereof

    Science.gov (United States)

    Rembaum, A.; Singer, S. (inventors)

    1970-01-01

    A thermally stable, relatively conductive polymer was disclosed. The polymer was synthesized by condensing in the presence of catalyst a 2, 4, or 6 nuclear alklylated 2, 3, or 4 pyridine aldehyde or quaternary derivatives thereof to form a polymer. The pyridine groups were liked by olefinic groups between 2-4, 2-6, 2-3, 3-4, 3-6 or 4-6 positions. Conductive compositions were prepared by dissolving the quaternary polymer and an organic charge transfer complexing agent such as TCNQ in a mutual solvent such as methanol.

  14. Conductive polymers: towards a smart biomaterial for tissue engineering.

    Science.gov (United States)

    Balint, Richard; Cassidy, Nigel J; Cartmell, Sarah H

    2014-06-01

    Developing stimulus-responsive biomaterials with easy-to-tailor properties is a highly desired goal of the tissue engineering community. A novel type of electroactive biomaterial, the conductive polymer, promises to become one such material. Conductive polymers are already used in fuel cells, computer displays and microsurgical tools, and are now finding applications in the field of biomaterials. These versatile polymers can be synthesised alone, as hydrogels, combined into composites or electrospun into microfibres. They can be created to be biocompatible and biodegradable. Their physical properties can easily be optimized for a specific application through binding biologically important molecules into the polymer using one of the many available methods for their functionalization. Their conductive nature allows cells or tissue cultured upon them to be stimulated, the polymers' own physical properties to be influenced post-synthesis and the drugs bound in them released, through the application of an electrical signal. It is thus little wonder that these polymers are becoming very important materials for biosensors, neural implants, drug delivery devices and tissue engineering scaffolds. Focusing mainly on polypyrrole, polyaniline and poly(3,4-ethylenedioxythiophene), we review conductive polymers from the perspective of tissue engineering. The basic properties of conductive polymers, their chemical and electrochemical synthesis, the phenomena underlying their conductivity and the ways to tailor their properties (functionalization, composites, etc.) are discussed. PMID:24556448

  15. White light generation tuned by dual hybridization of nanocrystals and conjugated polymers

    International Nuclear Information System (INIS)

    Dual hybridization of highly fluorescent conjugated polymers and highly luminescent nanocrystals (NCs) is developed and demonstrated in multiple combinations for controlled white light generation with high color rendering index (CRI) (> 80) for the first time. The generated white light is tuned using layer-by-layer assembly of CdSe/ZnS core-shell NCs closely packed on polyfluorene, hybridized on near-UV emitting nitride-based light emitting diodes (LEDs). The design, synthesis, growth, fabrication and characterization of these hybrid inorganic-organic white LEDs are presented. The following experimental realizations are reported: (i) layer-by-layer hybridization of yellow NCs (?PL=580 nm) and blue polyfluorene (?PL=439 nm) with tristimulus coordinates of (x, y)=(0.31, 0.27), correlated color temperature of Tc=6962 K and CRI of Ra=53.4; (ii) layer-by-layer assembly of yellow and green NCs (?PL=580 and 540 nm) and blue polyfluorene (?PL=439 nm) with (x, y)=(0.23, 0.30), Tc=14395 K and Ra=65.7; and (iii) layer-by-layer deposition of yellow, green and red NCs (?PL=580, 540 and 620 nm) and blue polyfluorene (?PL=439 nm) with (x, y)=(0.38, 0.39), Tc=4052 K and Ra= 83.0. The CRI is demonstrated to be well controlled and significantly improved by increasing multi-chromaticity of the NC and polymer emitters

  16. Anisotropic polymer composites synthesized by immobilizing cellulose nanocrystal suspensions specifically oriented under magnetic fields.

    Science.gov (United States)

    Tatsumi, Mio; Kimura, Fumiko; Kimura, Tsunehisa; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2014-12-01

    Novel polymer composites reinforced with an oriented cellulose nanocrystal (CNC) assembly were prepared from suspensions of CNC in aqueous 2-hydroxyethyl methacrylate (HEMA) via magnetic field application to the suspensions followed by polymerization treatment. The starting suspensions used at ?6 wt % CNC separated into an upper isotropic phase and a lower anisotropic (chiral nematic) one in the course of quiescent standing. A static or rotational magnetic field was applied to the isolated isotropic and anisotropic phases. UV-induced polymerization of HEMA perpetuated the respective states of magnetic orientation invested for the CNC dispersions to yield variously oriented CNC/poly(2-hydroxyethyl methacrylate) composites. The structural characterization was carried out by use of X-ray diffractometry and optical and scanning electron microscopy. The result indicated that CNCs were aligned in the composites distinctively according to the static or rotational magnetic application when the anisotropic phases were used, whereas such a specific CNC orientation was not appreciable when the isotropic phases were sampled. This marks out effectiveness of a coherent response of CNCs in the mesomorphic assembly. In dynamic mechanical experiments in tensile or compressive mode, we observed a clear mechanical anisotropy for the polymer composites synthesized from wholly anisotropic suspensions under static or rotational magnetization. The higher modulus (in compression) was detected for a composite reinforced by locking-in the uniaxial CNC alignment attainable through conversion of the initial chiral nematic phase into a nematic phase in the rotational magnetic field. PMID:25390070

  17. Thermophysical Properties of Polymer Materials with High Thermal Conductivity

    Science.gov (United States)

    Lebedev, S. M.; Gefle, O. S.; Dneprovskii, S. N.; Amitov, E. T.

    2015-06-01

    Results of studies on the main thermophysical properties of new thermally conductive polymer materials are presented. It is shown that modification of polymer dielectrics by micron-sized fillers allows thermally conductive materials with thermal conductivity not less than 2 W/(m K) to be produced, which makes it possible to use such materials as cooling elements of various electrical engineering and semiconductor equipment and devices.

  18. Colloidal infrared reflective and transparent conductive aluminum-doped zinc oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Buonsanti, Raffaella; Milliron, Delia J

    2015-02-24

    The present invention provides a method of preparing aluminum-doped zinc oxide (AZO) nanocrystals. In an exemplary embodiment, the method includes (1) injecting a precursor mixture of a zinc precursor, an aluminum precursor, an amine, and a fatty acid in a solution of a vicinal diol in a non-coordinating solvent, thereby resulting in a reaction mixture, (2) precipitating the nanocrystals from the reaction mixture, thereby resulting in a final precipitate, and (3) dissolving the final precipitate in an apolar solvent. The present invention also provides a dispersion. In an exemplary embodiment, the dispersion includes (1) nanocrystals that are well separated from each other, where the nanocrystals are coated with surfactants and (2) an apolar solvent where the nanocrystals are suspended in the apolar solvent. The present invention also provides a film. In an exemplary embodiment, the film includes (1) a substrate and (2) nanocrystals that are evenly distributed on the substrate.

  19. Ionic liquids as conducting additives for polymer nanocomposites.

    Czech Academy of Sciences Publication Activity Database

    Schrekker, H. S.; Donato, Ricardo Keitel; Mat?jka, Libor

    Prague : Institute of Macromolecular Chemistry AS CR, 2011. s. 87. ISBN 978-80-85009-69-9. [Prague Meeting on Macromolecules /75./ - Conducting Polymers - Formation, Structure, Properties, and Applications. 10.07.2011-14.07.2011, Prague] Institutional research plan: CEZ:AV0Z40500505 Keywords : ionic liquids * polymer nanocomposites Subject RIV: CD - Macromolecular Chemistry

  20. Making Conductive Polymers By Arc Tracking

    Science.gov (United States)

    Daech, Alfred F.

    1992-01-01

    Experimental technique for fabrication of electrically conductive polymeric filaments based on arc tracking, in which electrical arc creates conductive carbon track in material that initially was insulator. Electrically conductive polymeric structures made by arc tracking aligned along wire on which formed. Alignment particularly suited to high conductivity and desirable in materials intended for testing as candidate superconductors.

  1. Current Trends in Sensors Based on Conducting Polymer Nanomaterials

    Directory of Open Access Journals (Sweden)

    Hyeonseok Yoon

    2013-08-01

    Full Text Available Conducting polymers represent an important class of functional organic materials for next-generation electronic and optical devices. Advances in nanotechnology allow for the fabrication of various conducting polymer nanomaterials through synthesis methods such as solid-phase template synthesis, molecular template synthesis, and template-free synthesis. Nanostructured conducting polymers featuring high surface area, small dimensions, and unique physical properties have been widely used to build various sensor devices. Many remarkable examples have been reported over the past decade. The enhanced sensitivity of conducting polymer nanomaterials toward various chemical/biological species and external stimuli has made them ideal candidates for incorporation into the design of sensors. However, the selectivity and stability still leave room for improvement.

  2. Recent developments in intrinsically conductive polymer coatings for corrosion protection

    OpenAIRE

    M. Z. Iqbal; M. K. Zahoor; Hashim, S; Ali Usman Chaudhry; Khan, M.I.

    2010-01-01

    Intrinsically conductive polymers have achieved demanding interest in the field of corrosion control coatings owing to their conductive ability and also due to the strict environmental regulations on conventional heavy metals coatings. This multipurpose class of polymers has shown to be effective and proven themselves as a potential alternate for these hazardous heavy metal coatings in order to control the corrosion properties of metals or alloys. The basic purpose of this paper is only to hi...

  3. Conducting Polymers Functionalized with Phthalocyanine as Nitrogen Dioxide Sensors

    Directory of Open Access Journals (Sweden)

    S. D. Deshpande

    2002-05-01

    Full Text Available The conducting polymers such as polyaniline, polypyrrole and polythiophene were functionalized with copper phthalocyanine using chemical oxidation method. The obtained polymers viz. PANI-CuPc, PPy-CuPc and PT-CuPc were studied as chemical sensors by their response characteristics after exposure to various chemical vapors such as methanol, ammonia and nitrogen dioxide. The results obtained showed that these polymers have moderate sensitivity towards the methanol as well as ammonia vapors whereas they show tremendous sensitivity towards nitrogen dioxide vapors. The sensitivity factor of as high as 50,000 was obtained for PT-CuPc polymers in nitrogen dioxide. In comparison to this, the sensitivity factors of about 100 and 40 were obtained, when these polymers were exposed to ammonia and methanol vapors. The very high selectivity towards the nitrogen dioxide was explained on the basis of charge transfer complex formed between, the phthalocyanine donor and nitrogen dioxide acceptor molecules. On the other hand, ammonia becomes a competing electron donor in CuPc containing conducting polymers. The very low response towards the methanol may be explained on the basis very little charge transfer / interaction between CuPc containing polymers and methanol. Thus, CuPc incorporated conducting polymers have much higher selectivity than their original homopolymer.

  4. Characterisation of Proton Conducting Polymer Electrolyte Based on Pan

    Science.gov (United States)

    Nithya, S.; Selvasekarapandian, S.; Rajeswari, N.; Sikkanthar, S.; Karthikeyan, S.; Sanjeeviraja, C.

    2013-07-01

    The polymer electrolytes composed of polyacrylonitrile (PAN) with various concentration of ammonium nitrare (NH4NO3) salt have been prepared by solution casting method, using DMF as solvent. The increase in amorphous nature of the polymer electrolytes has been confirmed by Xray diffraction analysis. The complex formation between polymer and dissociated salt has been confirmed by Fourier transform infrared spectroscopy. From the Ac impedance spectroscopic analysis, the ionic conductivity of 20 mol% NH4NO3 doped polymer complex has been found to be 2.742 × 10-6 S cm-1 at room temperature. The conductivity has been increased when the temperature is increased. The activation energy of 20 mol% NH4NO3 doped polymer electrolyte was calculated using Arrhenius plot and it has been found to be 0.58 eV. The dielectric permitivitty (?*) and electric modulus (m*) have been discussed.

  5. Electrochemical characterization of ionically conductive polymer membranes.

    Czech Academy of Sciences Publication Activity Database

    Richau, K.; K?dela, Vlastimil; Schauer, Jan; Mohr, R.

    2002-01-01

    Ro?. 188, - (2002), s. 73-89. ISSN 1022-1360. [Microsymposium: Polymer Membranes /41./. Praha, 16.07.2001-19.07.2001] R&D Projects: GA AV ?R KSK4050111; GA MŠk ME 366 Institutional research plan: CEZ:AV0Z4050913 Keywords : fuel cell membrane * poly(phenylene oxide) Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.758, year: 2002

  6. Conducting polymers a new era in electrochemistry

    CERN Document Server

    Inzelt, György

    2008-01-01

    This book is a systematic survey of the knowledge accumulated in this field in the last thirty years. It includes material on the thermodynamic aspects of the polymers, the theory of the mechanism of charge transport processes, and the chemical and physical properties of these compounds. Also covered are the techniques of characterization, the electrochemical methods of synthesis, and the application of these systems. Inzelt's book is a must-read for electrochemists and others.

  7. Conducting Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2007-01-01

    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1-5 V), . Taking status after about 15 years of research efforts, most of these predictions have come true, the main exception being the much lower speeds actually realized in actuators.

  8. Conducting Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen Technical University of Denmark,

    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1-5 V), . Taking status after about 15 years of research efforts, most of these predictions have come true, the main exception being the much lower speeds actually realized in actuators.

  9. Conducting Polymer Electrodes for Gel Electrophoresis

    OpenAIRE

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel ...

  10. Radiation-induced electric conductivity of polymers under continuous irradiation

    International Nuclear Information System (INIS)

    Rdaiation-induced electyric conductivity of 15 polymers under continuous irradiation by electrons (60 and 75 keV energy) and by protons (7.7 MeV) within 1-104 Gr/s dose rate range at room temperature is studied. Parameters of all studied polymers, that is, Am, ? and ? are determined. Both free-charge (in PETPh, PS, PENPh, PPMI) and heminal (in PP, PTFE, PMMA etc.) mechanism of radiation electric conductivity is shown to occur. Mixed type of conductivity is observed in HPPE. Rouse-Fouler-Weisberg theory is modified for heminal electric conductivity case

  11. Top-down prepared silicon nanocrystals and a conjugated polymer-based bulk heterojunction: Optoelectronic and photovoltaic applications

    International Nuclear Information System (INIS)

    Blends consisting of doped silicon nanocrystals (Si-ncs) and two conjugated polymers (poly(3-hexylthiophene) (P3HT) and poly(methoxy ethylexyloxy phenylenevinilene) (MEH PPV)) with improved photostability were fabricated. We show that a top-down approach by electrochemical etching is suitable for preparing doped (boron and phosphorus) freestanding and surfactant-free Si-ncs. The doping of Si-ncs was confirmed by low temperature photoluminescence and electron spin resonance analysis. It is demonstrated that such Si-ncs can be successfully used for the fabrication of room temperature photoluminescent and photosensitive blends. We argue that the luminescence and transport properties of the blends are controlled by the Si-ncs properties and could be assigned to quantum confinement of excitons in nanocrystalites with an energy band gap of ?2 eV. Furthermore, the blending of doped Si-ncs in both conjugated polymers led to the establishment of a bulk heterojunction between the Si-ncs and polymer. The difference in electron affinity and ionization potential between nanocrystals and polymer dissociated the excitons. Those blends showed increased carrier transport and photoconductivity under ambient conditions. It was found that introduction of less defective p-type doped Si-ncs significantly improved overall photostability of the blend. The Si-ncs non-toxicity and easy integration into well-established silicon technologies might bring considerable benefit for hybrid optoelectronic and photovoltaic device development.

  12. Tuning Glass Transition in Polymer Nanocomposites with Functionalized Cellulose Nanocrystals through Nanoconfinement.

    Science.gov (United States)

    Qin, Xin; Xia, Wenjie; Sinko, Robert; Keten, Sinan

    2015-10-14

    Cellulose nanocrystals (CNCs) exhibit impressive interfacial and mechanical properties that make them promising candidates to be used as fillers within nanocomposites. While glass-transition temperature (Tg) is a common metric for describing thermomechanical properties, its prediction is extremely difficult as it depends on filler surface chemistry, volume fraction, and size. Here, taking CNC-reinforced poly(methyl-methacrylate) (PMMA) nanocomposites as a relevant model system, we present a multiscale analysis that combines atomistic molecular dynamics (MD) surface energy calculations with coarse-grained (CG) simulations of relaxation dynamics near filler-polymer interfaces to predict composite properties. We discover that increasing the volume fraction of CNCs results in nanoconfinement effects that lead to an appreciation of the composite Tg provided that strong interfacial interactions are achieved, as in the case of TEMPO-mediated surface modifications that promote hydrogen bonding. The upper and lower bounds of shifts in Tg are predicted by fully accounting for nanoconfinement and interfacial properties, providing new insight into tuning these aspects in nanocomposite design. Our multiscale, materials-by-design framework is validated by recent experiments and breaks new ground in predicting, without any empirical parameters, key structure-property relationships for nanocomposites. PMID:26340693

  13. FTIR AND IONIC CONDUCTIVITY STUDIES ON BLEND POLYMER ELECTROLYTES

    Directory of Open Access Journals (Sweden)

    J. Senthil

    2011-08-01

    Full Text Available Investigations on structural and conductivity properties of solid polymer complexes have attracted a high degree of attention. The main applications of solid polymer electrolytes (SPEs are found in varioussecondary batteries and energy conversion units. In view of the abundant resources, low costs and relatively low reactivity of magnesium, solid-state batteries using magnesium metal are worthy of investigations. The polymer electrolytes were prepared using poly methyl methacrylate (PMMA, poly vinyl chloride (PVC and magnesium chloride (MgCl2 by solvent casting technique. The complex formation and ionic conductivity were characterized by Fourier Transform Infra Red spectroscopy (FTIR and impedance spectroscopy respectively.The FTIR studies provide the evidence of interaction of cation Mg2+ with the polymers. The maximum conductivity found for PMMA-MgCl2 is 0.57 x 10-7 Scm-1 at room temperature.

  14. Synthesis, characterization and femtosecond nonlinear saturable absorption behavior of copper phthalocyanine nanocrystals doped-PMMA polymer thin films

    Science.gov (United States)

    Zongo, S.; Dhlamini, M. S.; Neethling, P. H.; Yao, A.; Maaza, M.; Sahraoui, B.

    2015-12-01

    In this work, we report the femtosecond nonlinear saturable absorption response of synthesized copper phthalocyanine nanocrystals (CPc-NCs)-doped PMMA polymer thin films. The samples were initially characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV-Vis and scanning electron microscopy (SEM) techniques. The crystalline phase and morphological analysis revealed nanocrystals of monoclinic structure with an average crystallite size between 31.38 nm and 42.5 nm. The femtosecond Z-scan study at 800 nm central wavelength indicated a saturable absorption behavior of which the mechanism is closely related to the surface plasmon resonance (SPR) of the particles. This nonlinear effect could potentially make the CPc-NCs useful in nonlinear optical devices.

  15. Intercalation of ionically conductive polymers into Lithium Hectorite

    Science.gov (United States)

    Saada, Iskandar

    Renewable energy sources such as wind and solar have become appealing sources of energy with low environmental impact. However, the challenge with using these energy sources is their intermittent and unpredictable power generation. In order to overcome this challenge, energy storage mechanisms such as lithium-ion batteries are dependable systems for such applications. The purpose of this project is intended to synthesize environmentally benign and safe materials which can be used as electrolytes in lithium-ion batteries. The ionically conductive polymers POEGO, POMOE, and MEEP were successfully intercalated into the two-dimensional layered structure Lithium Hectorite. The goal of the project was to synthesize a series of nanocomposites with increasing polymer molar ratios to Lithium Hectorite, and investigate the thermal and ionic conductivity properties of the synthesized nanocomposites. A second series of nanocomposites using the same polymer molar ratio to Lithium Hectorite were synthesized after the polymers were complexed with lithium triflate. The salt-complexed nanocomposites were compared to the pristine nanocomposites based on thermal stability, polymer flexibility, as well as their ionic conductivity. The synthesized polymers, nanocomposites, and salt-complexed materials were characterized using powder X-ray diffraction, attenuated total reflectance spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. Ionic conductivity data was investigated using AC impedance spectroscopy.

  16. Mediating conducting polymer growth within hydrogels by controlling nucleation

    Directory of Open Access Journals (Sweden)

    A. J. Patton

    2015-01-01

    Full Text Available This study examines the efficacy of primary and secondary nucleation for electrochemical polymerisation of conductive polymers within poly(vinyl alcohol methacrylate hydrogels. The two methods of nucleation investigated were a primary heterogeneous mechanism via introduction of conductive bulk metallic glass (Mg64Zn30Ca5Na1 particles and a secondary mechanism via introduction of “pre-polymerised” conducting polymer within the hydrogel (PEDOT:PSS. Evidence of nucleation was not seen in the bulk metallic glass loaded gels, however, the PEDOT:PSS loaded gels produced charge storage capacities over 15 mC/cm2 when sufficient polymer was loaded. These studies support the hypothesis that secondary nucleation is an efficient approach to producing stand-alone conducting hydrogels.

  17. A computer simulation study of ionic conductivity in polymer electrolytes

    CERN Document Server

    Bhattacharya, A J; Tarafdar, S; Bhattacharyya, Aninda Jiban

    1997-01-01

    In this paper we present a computer simulation study of ionic conductivity in solid polymeric electrolytes. The multiphase nature of the material is taken into account. The polymer is represented by a regular lattice whose sites represent either crystalline or amorphous regions with the charge carrier performing a random walk. Different waiting times are assigned to sites corresponding to the different phases. A random walk (RW) is used to calculate the conductivity through the Nernst-Einstein relation. Our walk algorithm takes into account the reorganisation of the different phases over time scales comparable to time scales for the conduction process. This is a characteristic feature of the polymer network. The qualitative nature of the variation of conductivity with salt concentration agrees with the experimental values for PEO-NH$_{4}$I and PEO-NH$_{4}$SCN. The average jump distance estimated from our work is consistent with the reported bond lengths for such polymers.

  18. Mediating conducting polymer growth within hydrogels by controlling nucleation

    Science.gov (United States)

    Patton, A. J.; Green, R. A.; Poole-Warren, L. A.

    2015-01-01

    This study examines the efficacy of primary and secondary nucleation for electrochemical polymerisation of conductive polymers within poly(vinyl alcohol) methacrylate hydrogels. The two methods of nucleation investigated were a primary heterogeneous mechanism via introduction of conductive bulk metallic glass (Mg64Zn30Ca5Na1) particles and a secondary mechanism via introduction of "pre-polymerised" conducting polymer within the hydrogel (PEDOT:PSS). Evidence of nucleation was not seen in the bulk metallic glass loaded gels, however, the PEDOT:PSS loaded gels produced charge storage capacities over 15 mC/cm2 when sufficient polymer was loaded. These studies support the hypothesis that secondary nucleation is an efficient approach to producing stand-alone conducting hydrogels.

  19. Lithium ion conducting solid polymer blend electrolyte based on bio-degradable polymers

    Indian Academy of Sciences (India)

    Natarajan Rajeswari; Subramanian Selvasekarapandian; Moni Prabu; Shunmugavel Karthikeyan; C Sanjeeviraja

    2013-04-01

    Lithium ion conducting polymer blend electrolyte films based on poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) with different Mwt% of lithium nitrate (LiNO3) salt, using a solution cast technique, have been prepared. The polymer blend electrolyte has been characterized by XRD, FTIR, DSC and impedance analyses. The XRD study reveals the amorphous nature of the polymer electrolyte. The FTIR study confirms the complex formation between the polymer and salt. The shifts in g values of 70 PVA–30 PVP blend and 70 PVA–30 PVP with different Mwt% of LiNO3 electrolytes shown by DSC thermograms indicate an interaction between the polymer and the salt. The dependence of g and conductivity upon salt concentration has been discussed. The ion conductivity of the prepared polymer electrolyte has been found by a.c. impedance spectroscopic analysis. The PVA–PVP blend system with a composition of 70 wt% PVA: 30 wt% PVP exhibits the highest conductivity of 1.58 × 10-6 Scm-1 at room temperature. Polymer samples of 70 wt% PVA–30 wt% PVP blend with different molecular weight percentage of lithium nitrate with DMSO as solvent have been prepared and studied. High conductivity of 6.828 × 10-4 Scm-1 has been observed for the composition of 70 PVA:30 PVP:25 Mwt% of LiNO3 with low activation energy 0.2673 eV. The conductivity is found to increase with increase in temperature. The temperature dependent conductivity of the polymer electrolyte follows the Arrhenius relationship which shows hopping of ions in the polymer matrix. The relaxation parameters () and () of the complexes have been calculated by using loss tangent spectra. The mechanical properties of polymer blend electrolyte such as tensile strength, elongation and degree of swelling have been measured and the results are presented.

  20. Stochastic System Identification of the Compliance of Conducting Polymers

    OpenAIRE

    Hunter, Ian; Pillai, Priam Vasudevan

    2008-01-01

    Conducting polymers such as polypyrrole, polythiophene and polyaniline are currently studied as novel biologically inspired actuators. The actuation mechanism of these materials depends upon the motion of ions in and out of the polymer film during electrochemical cycling. The diffusion of ions into the bulk of the film causes the dynamic mechanical compliance (or modulus) of the material to change during the actuation process. The mechanism of this change in compliance is not fully understood...

  1. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.; Larsen, Niels Bent; Hvilsted, Søren

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface. By use of an alkyne modified fluorescein derivative the reaction conditions have been optimized in a conventional MW oven, enabling the use of different sizes of substrates. The optimization resulted in a...

  2. Ionic motion in PEDOT and PPy conducting polymer bilayers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.

    2006-01-01

    Conducting polymer bilayers with poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), each containing dodecyl benzenesulfonate (DBS) as immobile dopant species, were synthesized galvanostatically. The electrochemical behaviour of the bilayers was investigated using cyclic voltammetry, optical absorption spectroscopy and electrochemical quartz crystal microbalance (EQCM) techniques. Two important conclusions of relevance for actuator performance were reached: It is possible to make a bilayer film that does not delaminate – the two polymers are compatible; and both polymers are active in the redox process as ions are able to move through the PEDOT layer and penetrate into PPy.

  3. Study of PEDOT conductive polymer films by admittance measurements

    International Nuclear Information System (INIS)

    Research highlights: ? Microwave technique to measure the conductivity of PEDOT films. ? PEDOT conductivity depends on its mesoscopic scale structure and oxidation level. ? Raman spectroscopy and SEM analysis to study structure and morphology of PEDOT. ? Microwave measurements allow determination of the macroscopic scale conductivity. ? Microwave measurements overcome problems related to the local structural defects and inhomogeneities of PEDOT. - Abstract: In this paper we propose the use of a microwave technique to measure the conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) films. The PEDOT layers were prepared by electropolymerization from aqueous solutions using both poly(sodium 4-styrene sulphonate) (NaPSS) and sodium dodecyl sulphate (NaDS) acting as monomer solubilizer and dopant for the polymer. The conductive properties of a series of samples produced under different synthesis conditions and characterized by different structures have been investigated by microwave measurements in the frequency range from 40 MHz to 40 GHz by using a Corbino disc geometry. Such technique allows to estimate the mean conductivity of the polymer samples overcoming the limitations of the measuring configurations typically imposed by the conventional d.c. measurements. The morphology of PEDOT films and the structure of polymer chains were studied by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The correlated morphological, structural and microwave analysis enabled us to evidence several factors that affect the macroscopic scale conductivity of the polymer sample films and to identify the conditions for preparation of PEDOT films with functional properties relevant to technological applications.

  4. Study of PEDOT conductive polymer films by admittance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tamburri, Emanuela, E-mail: Emanuela.Tamburri@uniroma2.it [Dip.to di Scienze e Tecnologie Chimiche and Interdisciplinary Micro and NAno-structured Systems laboratory (MINAS), Universita di Roma ' Tor Vergata' , Via Della Ricerca Scientifica, 00133 Roma (Italy); Sarti, Stefano [Dip.to di Fisica, Universita di Roma ' Sapienza' , P.le Aldo Moro 2, 00185 Roma (Italy); Orlanducci, Silvia; Terranova, Maria Letizia [Dip.to di Scienze e Tecnologie Chimiche and Interdisciplinary Micro and NAno-structured Systems laboratory (MINAS), Universita di Roma ' Tor Vergata' , Via Della Ricerca Scientifica, 00133 Roma (Italy); Rossi, Marco [Dip. di Scienze di Base e Applicate per l' Ingegneria, Universita di Roma ' Sapienza' , Via A. Scarpa 16, 00161 Roma (Italy)

    2011-02-15

    Research highlights: {yields} Microwave technique to measure the conductivity of PEDOT films. {yields} PEDOT conductivity depends on its mesoscopic scale structure and oxidation level. {yields} Raman spectroscopy and SEM analysis to study structure and morphology of PEDOT. {yields} Microwave measurements allow determination of the macroscopic scale conductivity. {yields} Microwave measurements overcome problems related to the local structural defects and inhomogeneities of PEDOT. - Abstract: In this paper we propose the use of a microwave technique to measure the conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) films. The PEDOT layers were prepared by electropolymerization from aqueous solutions using both poly(sodium 4-styrene sulphonate) (NaPSS) and sodium dodecyl sulphate (NaDS) acting as monomer solubilizer and dopant for the polymer. The conductive properties of a series of samples produced under different synthesis conditions and characterized by different structures have been investigated by microwave measurements in the frequency range from 40 MHz to 40 GHz by using a Corbino disc geometry. Such technique allows to estimate the mean conductivity of the polymer samples overcoming the limitations of the measuring configurations typically imposed by the conventional d.c. measurements. The morphology of PEDOT films and the structure of polymer chains were studied by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The correlated morphological, structural and microwave analysis enabled us to evidence several factors that affect the macroscopic scale conductivity of the polymer sample films and to identify the conditions for preparation of PEDOT films with functional properties relevant to technological applications.

  5. Preparation of Conducting Polymers by Electrochemical Methods and Demonstration of a Polymer Battery

    Science.gov (United States)

    Goto, Hiromasa; Yoneyama, Hiroyuki; Togashi, Fumihiro; Ohta, Reina; Tsujimoto, Akitsu; Kita, Eiji; Ohshima, Ken-ichi

    2008-01-01

    The electrochemical polymerization of aniline and pyrrole, and demonstrations of electrochromism and the polymer battery effect, are presented as demonstrations suitable for high school and introductory chemistry at the university level. These demonstrations promote student interest in the electrochemical preparation of conducting polymers, where…

  6. Light harvesting by dye linked conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Troensegaard Nielsen, K.

    2006-06-15

    The fact that the fossil fuel is finite and that the detrimental long-term effects of letting CO2 into our atmosphere exist, have created an enormous interest in developing new, cheap, renewable and less polluting energy resources. One of the most obvious abundant sources of energy in the solar system is the sun. Unfortunately the well developed silicon solar cells are very costly to produce. In an attempt to produce cheap and flexible solar cells, plastic solar cells have received a lot of attention in the last decades. There are still a lot of parameters to optimize if the plastic solar cell shall be able to compete with the silicon solar cells. One of the parameters is to ensure a high degree of charge carrier separation. Charge carrier separation can only happen at heterojunctions, which cover for example the interfaces between the polymers and the electrodes or the interface between an n-conductor and a p-conductor. The facts that the charge carrier separation only happens at the heterojunctions limits the thickness of the active layer in solar cells and thereby the effectiveness of the solar cells. In this project the charge carrier separation is attempted optimized by making plastic solar cells with a molecular heterojunction. The molecular heterojunction has been obtained by synthesizing a three domain super molecular assembly termed NPN. NPN consists of two poly[1-(2,5-dioctyltolanyl)ethynylene] chains (N-domains) coupled to the [10,20-bis(3,5-bistert-butylphenyl]-5,15-dibromoporphinato]zinc(II) (P-domain). It is shown that the N domains in NPN work as effective light harvesting antennas for the P domain and effectively transfer electrically generated excitons in the N domain to the P domain. Unfortunately the P domain does not separate the charge carriers but instead works as a charge carrier trap. This results in a performance of solar cells made of NPN that is much lower than the performance of solar cells made of pure poly[1-(2,5-dioctyltolanyl)- ethynylene], Nn. On the other hand light emitting diodes, LEDs, made of Nn and NPN works very well. The LEDs made of Nn emits greenish blue light while LEDs made of NPN emits light in the near-infrared region. During the synthesis of Nn and NPN it was found that remnants of the palladium catalysts caused problems in the control of the polymers and further made the resistance in the solar cells and LEDs so low that they did not work. A large effort has been made during the project to develop a method to remove remnants of metal catalysts from organic compounds and in particular polymers so that functional solar cells and LEDs could be made. It was succeeded to find a very effective method to remove remnants of metal catalysts from organic compounds by the discovery of the fact that azothioformamides are capable of dissolving metal nanoparticles by forming electron transfer complexes. Even metal wires of some metals can be dissolved by the azothioformamides within a reasonable time range. (au)

  7. Light harvesting by dye linked conducting polymers

    DEFF Research Database (Denmark)

    Nielsen, Kim Troensegaard

    2006-01-01

    The fact that the fossil fuel is finite and that the detrimental long-term effects of letting CO2 into our atmosphere exist, have created an enormous interest in developing new, cheap, renewable and less polluting energy resources. One of the most obviousabundant sources of energy in the solar system is the sun. Unfortunately the well developed silicon solar cells are very costly to produce. In an attempt to produce cheap and flexible solar cells, plastic solar cells have received a lot of attention inthe last decades. There are still a lot of parameters to optimize if the plastic solar cell shall be able to compete with the silicon solar cells. One of the parameters is to ensure a high degree of charge carrier separation. Charge carrier separationcan only happen at heterojunctions, which cover for example the interfaces between the polymers and the electrodes or the interface between an nconductor and a pconductor. The facts that the charge carrier separation only happens at the heterojunctionslimits the thickness of the active layer in solar cells and thereby the effectiveness of the solar cells. In this project the charge carrier separation is attempted optimized by making plastic solar cells with a molecular heterojunction. The molecularheterojunction has been obtained by synthesizing a three domain super molecular assembly termed NPN. NPN consists of two poly[1-(2,5- dioctyltolanyl)ethynylene] chains (N-domains) coupled to the [10,20- bis(3,5-bistert-butylphenyl]-5,15-dibromoporphinato]zinc(II) (P-domain). It is shown that the N domains in NPN work as effective light harvesting antennas for the P domain and effectively transfer electrically generated excitons in the N domain to the P domain.Unfortunately the P domain does not separate the charge carriers but instead works as a charge carrier trap. This results in a performance of solar cells made of NPN that is much lower than the performance of solar cells made of pure poly[1-(2,5-dioctyltolanyl)- ethynylene], Nn. On the other hand light emitting diodes, LEDs, made of Nn and NPN works very well. The LEDs made of Nn emits greenish blue light while LEDs made of NPN emits light in the nearinfrared region. During the synthesis of Nnand NPN it was found that remnants of the palladium catalysts caused problems in the control of the polymers and further made the resistance in the solar cells and LEDs so low that they did not work. A large effort has been made during the project todevelop a method to remove remnants of metal catalysts from organic compounds and in particular polymers so that functional solar cells and LEDs could be made. It was succeeded to find a very effective method to remove remnants of metal catalysts fromorganic compounds by the discovery of the fact that azothioformamides are capable of dissolving metal nanoparticles by forming electron transfer complexes. Even metal wires of some metals can be dissolved by the azothioformamides within a reasonable timerange.

  8. Conductivity of oriented bis-azo polymer films

    DEFF Research Database (Denmark)

    Apitz, D.; Bertram, R.P.; Benter, N.; Sommer-Larsen, P.; Johansen, P.M.; Buse, K.

    2006-01-01

    The conductivity properties of electro-optic photoaddressable, dense bis-ozo chromophore polymer films are investigated by using samples corona poled at various temperatures. A dielectric spectrometer is applied to measure the frequency dependence of the conductivity at different temperatures before and after heating the material to above the glass transition temperature. The results show that the orientation of the chromophores changes the charge-carrier mobility. Ionic conductivity dominates i...

  9. Exciton Dynamics in Alternative Solar Cell Materials: Polymers, Nanocrystals, and Small Molecules

    Science.gov (United States)

    Pundsack, Thomas J.

    To keep fossil fuel usage in 2040 even with 2010 usage, 50% of global energy will need to come from alternative sources such as solar cells. While the photovoltaic market is currently dominated by crystalline silicon, there are many low-cost solar cell materials such as conjugated polymers, semiconductor nanocrystals, and organic small molecules which could compete with fossil fuels. To create cost-competitive devices, understanding the excited state dynamics of these materials is necessary. The first section of this thesis looks at aggregation in poly(3-hexylthiophene) (P3HT) which is commonly used in organic photovoltaics. The amount of aggregation in P3HT thin films was controlled by using a mixture of regioregular and regiorandom P3HT. Even with few aggregates present, excited states were found to transfer from amorphous to aggregate domains in CZTS NCs) was measured using pump-probe spectroscopy and found to be in agreement with theoretical results. The density of states shifted and dilated for smaller NCs indicative of quantum confinement. The excited state lifetime was found to be short (CZTS photovoltaic devices. Finally, triplet-triplet annihilation (TTA) was studied in platinum octaethylporphyrin (PtOEP) thin films. By analyzing pump-probe spectra, the product of TTA in PtOEP thin films was assigned to a long-lived metal-centered state. To elucidate the mechanism of TTA, the annihilation dynamics were modeled using second order kinetics as well as Forster and Dexter energy transfer. Dexter energy transfer provided the best fits and the most reasonable fitting parameters.

  10. Ionic conductivity enhancement of polymer electrolytes with ceramic nanowire fillers.

    Science.gov (United States)

    Liu, Wei; Liu, Nian; Sun, Jie; Hsu, Po-Chun; Li, Yuzhang; Lee, Hyun-Wook; Cui, Yi

    2015-04-01

    Solid-state electrolytes provide substantial improvements to safety and electrochemical stability in lithium-ion batteries when compared with conventional liquid electrolytes, which makes them a promising alternative technology for next-generation high-energy batteries. Currently, the low mobility of lithium ions in solid electrolytes limits their practical application. The ongoing research over the past few decades on dispersing of ceramic nanoparticles into polymer matrix has been proved effective to enhance ionic conductivity although it is challenging to form the efficiency networks of ionic conduction with nanoparticles. In this work, we first report that ceramic nanowire fillers can facilitate formation of such ionic conduction networks in polymer-based solid electrolyte to enhance its ionic conductivity by three orders of magnitude. Polyacrylonitrile-LiClO4 incorporated with 15 wt % Li0.33La0.557TiO3 nanowire composite electrolyte exhibits an unprecedented ionic conductivity of 2.4 × 10(-4) S cm(-1) at room temperature, which is attributed to the fast ion transport on the surfaces of ceramic nanowires acting as conductive network in the polymer matrix. In addition, the ceramic-nanowire filled composite polymer electrolyte shows an enlarged electrochemical stability window in comparison to the one without fillers. The discovery in the present work paves the way for the design of solid ion electrolytes with superior performance. PMID:25782069

  11. Homogeneous Cu2ZnSnSe4 nanocrystals/graphene oxide nanocomposites as hole transport layer for polymer solar cells

    Science.gov (United States)

    Tan, Licheng; Zhang, Yan; Chen, Yiwang; Chen, Yufeng

    2015-02-01

    Homogeneous Cu2ZnSnSe4 nanocrystals/graphene oxide (CZTSe@GO) nanocomposite as hole transport layer (HTL) applied in polymer solar cells has been fabricated through a simple and solution-processed strategy, which not only arrests the aggregation of nanoparticles caused by ligand-exchanging, but also guarantees the intimate interfacial contact between graphene oxide and semiconductor nanocrystals. Comparing with Cu2ZnSnSe4 nanocrystals, the optimization of interfacial charge carrier transfer pathways for CZTSe@GO nanocomposites makes it more suitable as HTL which shows enhanced charge carrier transport and electron-blocking capacity, and well-matched work function facilitating collection of charges to anode. Besides, it also affords an efficient way to manufacture multifunctional nanocomposites based on nanocrystals.

  12. Corrosion-protective coatings from electrically conducting polymers

    Science.gov (United States)

    Thompson, Karen Gebert; Bryan, Coleman J.; Benicewicz, Brian C.; Wrobleski, Debra A.

    1991-01-01

    In a joint effort between NASA Kennedy and LANL, electrically conductive polymer coatings were developed as corrosion protective coatings for metal surfaces. At NASA Kennedy, the launch environment consist of marine, severe solar, and intermittent high acid and/or elevated temperature conditions. Electrically conductive polymer coatings were developed which impart corrosion resistance to mild steel when exposed to saline and acidic environments. Such coatings also seem to promote corrosion resistance in areas of mild steel where scratches exist in the protective coating. Such coatings appear promising for many commercial applications.

  13. Effects of preparation temperature on the conductivity of polypyrrole conducting polymer

    Indian Academy of Sciences (India)

    Anuar Kassim; Zarina Bte Basar; H N M Ekramul Mahmud

    2002-04-01

    An attempt has been made to investigate the effect of temperature on the conductivity of polypyrrole conducting polymer films prepared by an electrochemical method in an aqueous medium using camphor sulfonate as the dopant. The polymer was grown from aqueous solutions employing a range of temperatures (1-60°C). It was found that with increase in temperature the conductivity decreased and the optimum temperature was found to be between 10 and 30°C. The results show that the polymer formed at low temperature has higher conductivity and is stronger than that formed at higher temperatures. Characterization by X-ray scattering shows that interlayer distance, $d_{\\text{Bragg}}$ (Å), increases with increasing temperature. The morphology of the films formed was studied by using a scanning electron microscope (SEM). The changes in conductivity and physical appearance were interpreted as being due to compactness in the molecular packing and formation of $\\alpha \\beta$ linkages in the film.

  14. Decoupled ion conduction mechanism of poly(vinyl alcohol) based Mg-conducting solid polymer electrolyte

    International Nuclear Information System (INIS)

    Investigation on solid state rechargeable magnesium batteries are considered important similar to lithium batteries. In view of negligible hazard and less reactivity of the magnesium, in comparison with lithium, studies on rechargeable magnesium batteries are expected to have a wide scope in future. In the present investigations, decoupled ion conduction of poly(vinyl alcohol) (PVA)-based Mg-conducting solid polymer electrolytes (SPEs) is essential component of the studies. In common SPEs, ion transport has mostly been associated with the segmental motion of the polymer, so significant conductivity is only observed above the glass transition temperature of the system. But the results of ac impedance spectroscopy, FT-IR, XRD and AFM indicated that prepared PVA-based Mg-conducting SPE shows ionic transport decoupled from polymer segmental motion and high ionic conductivity at room temperature

  15. Proton Ion Conducting Polymer Electrolyte Pan: NH4PF6

    Science.gov (United States)

    Sikkanthar, S.; Karthikeyan, S.; Rajeswari, N.; Selvasekarapandian, S.; Sanjeeviraja, C.

    2013-07-01

    Polymer electrolytes are an important class of materials and have been used in high energy batteries, fuel cells, gas sensors, display devices etc. PAN based polymer electrolyte films doped with ammonium hexafluorophosphate (NH4PF6) has been prepared by the solution casting method. The prepared films have been investigated by different techniques such as XRD, FTIR and AC Impedance spectroscopy. XRD studies reveal the amorphous nature of the polymer blend-salt complexes. The FTIR analysis confirms the complex formation of the polymer with salt. From the AC Impedance spectroscopy, the maximum proton conductivity at room temperature has been found to be 3.98×10-4 S cm-1 for 20 mol% salt doped electrolyte.

  16. Thin film conductive polymer for microactuator and micromuscle applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.P.; Hong, K.; Trevino, J.; Northrup, M.A.

    1994-04-14

    Conductive polymer/polyimide bimorphic microcantilevers have been actuated vertically (out-of-plane) upon the volumetric changes induced by electrochemical doping of the polymer. The microcantilevers that are 200-500 {mu}m in length and 50-100 {mu}m in width can be fully extended from a circularly-curled geometry, and thus generate more than 100 {mu}m displacement. Dynamically the microcantilevers have been driven as fast as 1.2 Hz and the polymer was stable for over a week stored in air and light. Residual stresses in the polymer film is estimated to be as high as 254 MPa, and actuation stresses are as high as 50 MPa.

  17. Maximum conductivity of packed nanoparticles and their polymer composites.

    Science.gov (United States)

    Untereker, Darrel; Lyu, Suping; Schley, James; Martinez, Gonzalo; Lohstreter, Lance

    2009-01-01

    Adding conductive fillers to nonconductive polymers is a common way to make soft conductive materials such as conductive adhesives. An important issue is how to achieve high volume conductivity with acceptable mechanical performance. Two questions pertaining to this issue were studied in this paper. One question was whether the maximum conductivity benefits from larger or smaller particle sizes. The second was what is the maximum achievable conductivity. One incentive for this work is the recent availability of nanomaterials that provide opportunities to make conductive composites using much smaller particles than in the past. We found that the conductivity of platinum, carbon black, and silver particles in their polyurethane composites did not vary greatly with particle size (from micrometer to nanometer range). What was unexpected was that in all the composite examples, the highest conductivity achieved was only on the order of 1% of that of the pure bulk conductive materials. Further experiments to emulate these conductive composites with platinum, carbon black, copper, and nickel particles without polymer matrix showed similar results, indicating the issue is not simply dispersion homogeneity, nano versus macro particles, particle connectivity/percolation, or the presence of the matrix materials. We interpret this to mean that the composite systems are intrinsically limited by the contact between filler particles. PMID:20355760

  18. Radiation induced synthesis of conducting polymer nanocomposite

    International Nuclear Information System (INIS)

    In this work, we prepared a series of Ag/PVA and Ag/PANI nano composites were prepared successfully using a modern and new method. Our synthetic route did not need complicated apparatus, expensive surfactants or additional reducing agents. The prepared nano composite developed optically functional material that does not exist for metal or polymer alone. The present work contains five chapters in addition to the list of figures, tables, abbreviations and references. The first two chapters are concerned with the introduction and reviews of previous studies. Chapter 3 describes the preparation methodology, experimental setup and techniques used in the Ag/PVA and Ag/PANI nano composites processing and analysis. Ag nanoparticles with different particle sizes were prepared via chemical method and gamma- irradiation method. Several techniques were used to detect the structural changes of the nano composites as UV-Visible spectrophotometer, Transmission Electron microscope (TEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectrometer, and thermogravimetric analysis (TGA). Chapter 4 includes the obtained results and their discussions: Part I: Synthesis of Ag/PVA nano composite via gamma irradiation From UV/VIS spectroscopy the surface plasmon bands appearing in the visible region (406-422 nm) for Ag/PVA nano composite films are characteristic of the noble metal nanoparticles. The obtained data regarding the change of the absorption intensity and wavelength at maximum absorption and the size of Ag nanoparticles as a function of either irradiation dose or Ag+ concentration pointed the following remark: The particle size of Ag nanoparticles in the as-prepared Ag/PVA nano composite films decreases with increasing either irradiation dose or Ag+ ion concentration. Transmission electron microscope images illustrated that the average diameter of the Ag nanoparticles is indicated as the peak position of the Gaussian curves of the histogram to be from 40-16 nm. The nano structured Ag/PVA films were found to be dispersed spherical nanoparticles with good structural homogeneity and polydispersity. The XRD pattern of irradiated Ag/PVA nano composite samples show four new diffraction peaks which reveal that the Ag nanoparticles are formed in the PVA matrix and their crystal structure is face center cubic (fcc) structure. Also, it can be seen that, with increasing irradiation dose, the particle size decreases, whereas the particle size increase gradually with increasing AgNO3 concentration. FTIR spectra illustrate that the formation of Ag/PVA nano composites leads to disappearance and/or weakening of some characteristic peaks followed by the change in peak position, peak shape and peak intensity due to incorporation of various content of Ag nanoparticles and irradiation doses. Decrease in the transmittance of some bands reveals that there is an interaction between Ag and PVA. Thermal gravimetric analysis (TGA) showed that, pure PVA sample proceed in three main weight loss stages. The appearance of the fourth stage with incorporation of Ag nanoparticles; confirm the coordination between AgNPs and OH groups. Finally, from the thermal parameters of Ag/PVA degradation reaction, thermal stability of Ag/PVA nano composites is higher than in pure PVA. The antifungal and antibacterial activities of AgNPs were tested against some of pathogenic clinical isolates and some of gram-positive S. aureus and some gram-negative E. coli, respectively. AgNPs exhibited a potent antifungal and antibacterial activity against some of fungal and bacterial strains tested. The antifungal and antibacterial activity increases (according to increase the high specific surface area) with either increasing irradiation dose or decreasing AgNO3 concentration. Part II: Synthesis of Ag/PANI nano composite via gamma irradiation UV/VIS absorption shows the formation and growth of Ag nanoparticles through absorption band at (398-406). For a given samples, as the irradiation dose is increased, a gradual red shift in was observed. This indicates formation of larger par

  19. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface. By use of an alkyne modified fluorescein derivative the reaction conditions have been optimized in a conventional MW oven, enabling the use of different sizes of substrates. The optimization resulted in a reduction of reaction times of approximately 20h to only 2min for bulk film functionalization. The method has been applied for anchoring of the chelating agent nitrilotriacetic acid (NTA) on the conductive polymer. The chelating linkage ability of NTA on the surface was investigated through a sandwich ELISA study confirming the selective bonding of a histidine tagged protein.

  20. Synthesis of proton conducting polymer based on poly(silamine)

    Energy Technology Data Exchange (ETDEWEB)

    Tsuruhara, Koji; Rikukawa, Masahiro; Sanui, Kohei; Ogata, Naoya; Kato, Masao [Sophia Univ., Tokyo (Japan). Dept. of Chemistry; Nagasaki, Yukio [Science Univ. of Tokyo, Chiba (Japan). Dept, of Materials Science and Technology

    2000-07-01

    New proton conducting polymers based on poly(silamine) (PSA) were synthesized by complexing the polymer and H{sub 3}PO{sub 4}, and the proton conduction of these materials was investigated. The PSA/H{sub 3}PO{sub 4} complex was thermally stable up to 200{sup o}C, as indicated by TG/DTA analysis. The conductivity of 10{sup -5} S cm{sup -1} was observed at 160{sup o}C for anhydrous PSA/H{sub 3}PO{sub 4} complexes with a concentration of 0.8 H{sub 3}PO{sub 4} per repeat unit. The carrier ion was proven to be proton on the basis of the H/D isotope effect on conductivity for PSA/H{sub 3}PO{sub 4} and PSA/D{sub 3}PO{sub 4} complexes. (Author)

  1. Conducting polymer based materials for the fuel cell applications.

    Czech Academy of Sciences Publication Activity Database

    Sapurina, I. Yu.; Stejskal, Jaroslav; Kompan, M.

    Sankt Peterburg : Fiziko-techni?eskij Institut im. A. F. Ioffe, 2005. s. 39. [Meždunarodnyj Seminar: Rossijskie technologii dlja industrii /9./. 30.5.2005-1.6.2005, Sankt Peterburg] Institutional research plan: CEZ:AV0Z40500505 Keywords : fuel cell * conducting polymers Subject RIV: CD - Macromolecular Chemistry

  2. Ionic motion in PEDOT and PPy conducting polymer bilayers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

    2006-01-01

    Conducting polymer bilayers with poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), each containing dodecyl benzenesulfonate (DBS) as immobile dopant species, were synthesized galvanostatically. The electrochemical behaviour of the bilayers was investigated using cyclic voltammetry, optical absorption spectroscopy and electrochemical quartz crystal microbalance (EQCM) techniques. Two important conclusions of relevance for actuator performance were reached: It is possible to make a b...

  3. The conversion of conducting polymers to nitrogen-containing carbons.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Trchová, Miroslava

    Riva del Garda : Elsevier, 2013. P1.011. [International Conference on Diamond and Carbon Materials 2013. 02.09.2013-05.09.2013, Riva del Garda] R&D Projects: GA ?R GAP205/12/0911 Institutional support: RVO:61389013 Keywords : conducting polymer * polyaniline * carbon Subject RIV: CD - Macromolecular Chemistry

  4. Purification of a conducting polymer, polyaniline, for biomedical applications.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Hajná, Milena; Kašpárková, V.; Humpolí?ek, P.; Zhigunov, Alexander; Trchová, Miroslava

    2014-01-01

    Ro?. 195, September (2014), s. 286-293. ISSN 0379-6779 R&D Projects: GA ?R(CZ) GA13-08944S Institutional support: RVO:61389013 Keywords : biocompatibility * conducting polymer * polyaniline Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.252, year: 2014

  5. Soft capacitor fibers using conductive polymers for electronic textiles

    OpenAIRE

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-01-01

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its crossection the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometres of fibers can be obtained from a si...

  6. Thiophene in Conducting Polymers: Synthesis of Poly(thiophene)s and Other Conjugated Polymers Containing Thiophenes, for Application in Polymer Solar Cells

    DEFF Research Database (Denmark)

    Livi, Francesco; Carlé, Jon Eggert; Bundgaard, Eva

    2015-01-01

    Conducting polymers based on thiophene are described. The polymers include poly(thiophene) with and without side-chains and other conjugated polymers in general, based on thiophene. The synthesis and characteristics of the polymers are described along with the application of these as light-absorbing materials in polymer solar cells.

  7. New secondary batteries utilizing electronically conductive polymer cathodes

    Science.gov (United States)

    Martin, Charles R.; White, Ralph E.

    1989-01-01

    The objectives of this project are to characterize the transport properties in electronically conductive polymers and to assess the utility of these films as cathodes in lithium/polymer secondary batteries. During this research period, progress has been made in a literature survey of the historical background, methods of preparation, the physical and chemical properties, and potential technological applications of polythiophene. Progress has also been made in the characterization of polypyrrole flat films and fibrillar films. Cyclic voltammetry and potential step chronocoulometry were used to gain information on peak currents and potentials switching reaction rates, charge capacity, and charge retention. Battery charge/discharge studies were also performed.

  8. Conduction mechanisms in silicon-polymer-metal heterostructures

    International Nuclear Information System (INIS)

    Conduction mechanisms in thin films of wide-gap polymers in silicon-based heterostructures have been experimentally studied. Measuring the temperature dependence of the current-voltage characteristics of samples in the temperature range 80-300 K was used as the basic method. Multilayer Si-SiO2-polymer-metal structures were prepared for measurements. Films of poly(diphenylene phthalide), in which a transition from the insulating to a highly conducting state is observed, were used as polymeric layers. The results obtained were used to explain the features of the charge transport in the samples in terms of the hopping conductivity via trap levels, Schottky emission, and field-assisted tunneling emission

  9. Carboxy-Endcapped Conductive Polypyrrole: Biomimetic Conducting Polymer for Cell Scaffolds and Electrodes

    OpenAIRE

    Lee, Joo-Woon; Serna, Francisco; Schmidt, Christine E

    2006-01-01

    Numerous regenerating tissues respond favorably to electrical stimulation, creating a need for a bioactive conducting platform for tissue engineering applications. The drive for biosensors and electrode coatings further requires control of the surface properties of promising conductive materials such as polypyrrole. Here we present carboxy-endcapped polypyrrole (PPy-?-COOH), a unique bioactive conducting polymer with a carboxylic acid layer, composed of a polypyrrole (PPy) surface modified wi...

  10. Confinement-induced nanocrystal alignment of conjugated polymer by the soft-stamped nanoimprint lithography

    Science.gov (United States)

    Li, Xiao-Hui; Yu, Ji-Cheng; Lu, Nai-Yan; Zhang, Wei-Dong; Weng, Yu-Yan; Gu, Zhen

    2015-10-01

    Soft-stamped nanoimprint lithography (NIL) is considered as one of the most effective processes of nanoscale patterning because of its low cost and high throughput. In this work, this method is used to emboss the poly (9, 9-dioctylfluorene) film. By reducing the linewidth of the nanogratings on the stamp, the orientations of nanocrystals are confined along the grating vector in the nanoimprint process, where the confinement linewidth is comparable to the geometrical size of the nanocrystal. When the linewidth is about 400 nm, the poly (9, 9-dioctylfluorene) (PFO) nanocrystals could be orderly arranged in the nanogratings, so that both pattern transfer and well-aligned nanocrystal arrangement could be achieved in a single step by the soft-stamped NIL. The relevant mechanism of the nanocrystalline alignment in these nanogratings is fully discussed. The modulation of nanocrystal alignment is of benefit to the charge mobilities and other performances of PFO-based devices for the future applications. Project supported by the National Natural Science Foundation of China (Grant No. 21204058).

  11. Luminescence quenching of conductive Si nanocrystals via “Linkage emission”: Hopping-like propagation of infrared-excited Auger electrons

    International Nuclear Information System (INIS)

    Phosphorus (P) is an n-type dopant for conductive silicon nanocrystals (Si-nc's), the electrical activation of which may be monitored through a non-radiative Auger recombination process that quenches the Si-nc luminescence. We investigated this quenching mechanism through electrical measurements of Si-nc's. Infrared-excited Auger electron emission as the non-radiative process was directly probed and the dynamics of the process are determined from a frequency response analysis. To explain the dynamics, we propose a model in which Auger electrons with a low kinetic energy establish a local inter-nanocrystal conductance and the repetition of this local conductance results in a constant photocurrent (“linkage emission”). This emission becomes significant by electron filling in the Si-nc's owing to the electrical activation of P, which is consistent with observed luminescence quenching behavior. We found that the IR photo-excited emission is distinct from the thermally induced hopping conduction and show that confined, rather than trapped, charges are the source of the Auger electrons. Thus, the process consumes both confined charges and the recombination energy for Auger emission, which explains the luminescence quenching mechanism of Si-nc:P

  12. Investigations of proton conducting polymers and gas diffusion electrodes in the polymer electrolyte fuel cell

    OpenAIRE

    Gode, Peter

    2005-01-01

    Polymer electrolyte fuel cells (PEFC) convert the chemically bound energy in a fuel, e.g. hydrogen, directly into electricity by an electrochemical process. Examples of future applications are energy conversion such as combined heat and power generation (CHP), zero emission vehicles (ZEV) and consumer electronics. One of the key components in the PEFC is the membrane / electrode assembly (MEA). Both the membrane and the electrodes consist of proton conducting polymers (ionomers). In the membr...

  13. Kinetic features of radiation-induced electric conductivity in polymers

    International Nuclear Information System (INIS)

    Dependence of radiation-induced electric conductivity (EC) of certain polymers on the time of irradiation by accelerated electrons (75 keV in the range of dose rate D = 20-500 Gy/s) with varying irradiation temperature, dose rate and electric field intensity has been studied. Existence of three stages of EC increase has been revealed in all the polymers studied: 'instant' (time of increment t << 1 s), 'fast' (t = 1-10 s) and 'decelerated' (t = 10-1000 s). It is shown that kinetic regularities of polymer EC can not be coordinated in the framework of the model of multiple capture of charges. The conclusion is made on determining role of molecular mobility in transfer of charge carriers generated by ionizing radiation. 12 refs., 4 figs., 1 tab

  14. Electrically conductive, optically transparent polymer/carbon nanotube composites

    Science.gov (United States)

    Connell, John W. (Inventor); Smith, Jr., Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor); Park, Cheol (Inventor); Watson, Kent A. (Inventor); Ounaies, Zoubeida (Inventor)

    2011-01-01

    The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

  15. Synthesis of polymer nanostructures with conductance switching properties

    Science.gov (United States)

    Su, Kai; Nuraje, Nurxat; Zhang, Lingzhi; Matsui, Hiroshi; Yang, Nan Loh

    2015-03-03

    The present invention is directed to crystalline organic polymer nanoparticles comprising a conductive organic polymer; wherein the crystalline organic polymer nanoparticles have a size of from 10 nm to 200 nm and exhibits two current-voltage states: (1) a high resistance current-voltage state, and (2) a low resistance current-voltage state, wherein when a first positive threshold voltage (V.sub.th1) or higher positive voltage, or a second negative threshold voltage (V.sub.th2) or higher negative voltage is applied to the nanoparticle, the nanoparticle exhibits the low-resistance current-voltage state, and when a voltage less positive than the first positive threshold voltage or a voltage less negative than the second negative threshold voltage is applied to the nanoparticle, the nanoparticle exhibits the high-resistance current-voltage state. The present invention is also directed methods of manufacturing the nanoparticles using novel interfacial oxidative polymerization techniques.

  16. Stably Doped Conducting Polymer Nanoshells by Surface Initiated Polymerization.

    Science.gov (United States)

    Li, Junwei; Yoon, Soon Joon; Hsieh, Bao-Yu; Tai, Wanyi; O'Donnell, Matthew; Gao, Xiaohu

    2015-12-01

    Despite broad applications ranging from electronics to biomedical sensing and imaging, a long-standing problem of conducting polymers is the poor resistance to dedoping, which directly affects their signature electrical and optical properties. This problem is particularly significant for biomedical uses because of fast leaching of dopant ions in physiological environments. Here, we describe a new approach to engineer multimodal core-shell nanoparticles with a stably doped conductive polymer shell in biological environments. It was achieved by making a densely packed polymer brush rather than changing its molecular structure. Polyaniline (PANI) was used as a model compound due to its concentrated near-infrared (NIR) absorption. It was grafted onto a magnetic nanoparticle via a polydopamine intermediate layer. Remarkably, at pH 7 its conductivity is ca. 2000× higher than conventional PANI nanoshells. Similarly, its NIR absorption is enhanced by 2 orders of magnitude, ideal for photothermal imaging and therapy. Another surprising finding is its nonfouling property, even outperforming polyethylene glycol. This platform technology is also expected to open exciting opportunities in engineering stable conductive materials for electronics, imaging, and sensing. PMID:26588215

  17. Interdiffusion and Spinodal Decomposition in Electrically Conducting Polymer Blends

    Directory of Open Access Journals (Sweden)

    Antti Takala

    2015-08-01

    Full Text Available The impact of phase morphology in electrically conducting polymer composites has become essential for the efficiency of the various functional applications, in which the continuity of the electroactive paths in multicomponent systems is essential. For instance in bulk heterojunction organic solar cells, where the light-induced electron transfer through photon absorption creating excitons (electron-hole pairs, the control of diffusion of the spatially localized excitons and their dissociation at the interface and the effective collection of holes and electrons, all depend on the surface area, domain sizes, and connectivity in these organic semiconductor blends. We have used a model semiconductor polymer blend with defined miscibility to investigate the phase separation kinetics and the formation of connected pathways. Temperature jump experiments were applied from a miscible region of semiconducting poly(alkylthiophene (PAT blends with ethylenevinylacetate-elastomers (EVA and the kinetics at the early stages of phase separation were evaluated in order to establish bicontinuous phase morphology via spinodal decomposition. The diffusion in the blend was followed by two methods: first during a miscible phase separating into two phases: from the measurement of the spinodal decomposition. Secondly the diffusion was measured by monitoring the interdiffusion of PAT film into the EVA film at elected temperatures and eventually compared the temperature dependent diffusion characteristics. With this first quantitative evaluation of the spinodal decomposition as well as the interdiffusion in conducting polymer blends, we show that a systematic control of the phase separation kinetics in a polymer blend with one of the components being electrically conducting polymer can be used to optimize the morphology.

  18. Conducting polymer/carbon nanocoil composite electrodes for efficient supercapacitors

    KAUST Repository

    Baby, Rakhi Raghavan

    2012-01-01

    Herein, we report for the first time, conducting polymer (polyaniline (PANI) and polypyrrole (PPY)) coated carbon nanocoils (CNCs) as efficient binder-free electrode materials for supercapacitors. CNCs act as a perfect backbone for the uniform distribution of the conducting polymers in the composites. In two electrode configuration, the samples exhibited high specific capacitance with the values reaching up to 360 and 202 F g -1 for PANI/CNCs and PPY/CNCs respectively. The values obtained for specific capacitance and maximum storage energy per unit mass of the composites were found to be comparable to one of the best reported values for polymer coated multi-walled carbon nanotubes. In addition, the fabricated PANI/CNC based supercapacitors exhibited a high value of 44.61 Wh kg -1 for maximum storage energy per unit mass. Although the devices exhibit an initial capacitance loss due to the instability of the polymer, the specific capacitance stabilizes at a fixed value after 500 charge-discharge cycles. © 2012 The Royal Society of Chemistry.

  19. Sub-Micrometer Size Structure Fabrication Using a Conductive Polymer

    Directory of Open Access Journals (Sweden)

    Junji Sone

    2014-12-01

    Full Text Available Stereolithography that uses a femtosecond laser was employed as a method for multiphoton-sensitized polymerization. We studied the stereolithography method, which produces duplicate solid shapes corresponding to the trajectory of the laser focus point and can be used to build a three-dimensional (3D structure using a conductive polymer. To achieve this, we first considered a suitable polymerization condition for line stereolithography. However, this introduced a problem of irregular polymerization. To overcome this, we constructed a support in the polymerized part using a protein material. This method can stabilize polymerization, but it is not suited for building 3D shapes. Therefore, we considered whether heat accumulation causes the irregular polymerization; consequently, the reduction method of the repetition rate of the femtosecond laser was used to reduce the heating process. This method enabled stabilization and building of a 3D shape using photo-polymerization of a conductive polymer.

  20. Electroless deposition of conducting polymers using the scanning electrochemical microscope

    Energy Technology Data Exchange (ETDEWEB)

    Borgwarth, K.; Ricken, C.; Heinze, J. [Freiburg Univ. (Germany). Inst. fuer Physikalische Chemie; Rohde, N.; Hallensleben, M.L.; Mandler, D.

    1999-10-01

    Micropatterning of organic substances using scanning electrochemical microscopy (SECM) is presented as a versatile, reproducible method for obtaining patterned materials of mesoscopic resolution-between that of conventional lithography and scanning tunneling microscopy or atomic force microscopy. In this technique, conducting polymer is electrolessly deposited on different substrates. It is reported that both flat layers and sets of thin needles protruding from the surface may be formed simply by varying the nature of the redox mediator. (orig.)

  1. Coating of zinc ferrite particles with a conducting polymer, polyaniline.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Trchová, Miroslava; Brodinová, J.; Kalenda, P.; Fedorova, S.; Prokeš, J.; Zemek, Josef

    2006-01-01

    Ro?. 298, ?. 1 (2006), s. 87-93. ISSN 0021-9797 R&D Projects: GA AV ?R IAA4050313; GA AV ?R IAA400500504; GA ?R GA202/06/0419; GA ?R GA202/06/0459 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z10100521 Keywords : conducting polymers * polyaniline Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.233, year: 2006

  2. Electrofragmentation modeling of conductive coatings on polymer substrates

    OpenAIRE

    Leterrier, Yves; Pinyol, Albert; Rougier, Luc; Waller, Judith H.; Månson, Jan-Anders E.

    2009-01-01

    Damage occurring under tensile loading and the resulting increase of electrical resistance of indium-doped tin oxide and amorphous graphite coatings on various polymer substrates are investigated, using an electro-fragmentation method in situ in an optical microscope. The electrical resistance is modeled as a function of damage state assuming that the resistance of coating cracks is proportional to their opening, and that there exists a conducting path of constant thickness at the coating/sub...

  3. Pedot and PPy Conducting Polymer Bilayer and Trilayer Actuators

    DEFF Research Database (Denmark)

    Zainudeen, Umer Lebbe; Careem, Mohamed Abdul; Skaarup, Steen

    2008-01-01

    Actuators based on conducting polymers are attracting increasing interest due to their desirable features such as large mechanical stress generated, sufficient maximum strain values, high reversibility, good safety properties and the possibility of precise control using small voltages. Many attempts have been made to improve the actuator performance. We report electromechanical measurements on actuators of bilayer and trilayer free standing films prepared with polypyrrole (PPy) and poly(3,4-ethy...

  4. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

    OpenAIRE

    Tsukada, Shingo; Nakashima, Hiroshi; Torimitsu, Keiichi

    2012-01-01

    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in bot...

  5. Pedot and PPy Conducting Polymer Bilayer and Trilayer Actuators

    DEFF Research Database (Denmark)

    Zainudeen, Umer Lebbe; Careem, Mohamed Abdul

    2008-01-01

    Actuators based on conducting polymers are attracting increasing interest due to their desirable features such as large mechanical stress generated, sufficient maximum strain values, high reversibility, good safety properties and the possibility of precise control using small voltages. Many attempts have been made to improve the actuator performance. We report electromechanical measurements on actuators of bilayer and trilayer free standing films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers. Both types of conducting polymer are pre-doped during synthesis with dodecyl benzenesulfonate (DBS). These multilayer films were prepared electrochemically so that the PEDOT layer is very thin compared to that of the PPy layer. In the trilayer film, the PEDOT layer is sandwiched between two PPy layers.The films were characterized electromechanically and the results compared with those of PPy single layer film. Bilayer films show a significant increase in the strain measured at higher scan rates (>100mVs?1). The force difference generated between the reduced and oxidized states is much higher for trilayer films and higher for bilayer films than that in a single layer of PPy. Trilayer films are both stronger and faster than a single layer PPy film of half the thickness.

  6. Feasibility and benefits of using interdigitated electrodes for conductivity measurements on conducting polymers.

    Czech Academy of Sciences Publication Activity Database

    Varga, M.; Prokeš, J.; Konyushenko, Elena; Stejskal, Jaroslav

    Atlanta : Center for Organic Photonics and Electronics - Georgia Institute of Technology, 2012. s. 324. [International Conference on Science and Technology of Synthetic Metals 2012 - ICSM 2012. 08.07.2012-13.07.2012, Atlanta] Institutional support: RVO:61389013 Keywords : conducting polymers * interdigitated electrodes Subject RIV: CD - Macromolecular Chemistry

  7. Critical Dependence of Polarization Phenomena on Conductivity in Ferroelectric Polymers

    Directory of Open Access Journals (Sweden)

    S.N. Fedosov

    2014-01-01

    Full Text Available Experimentally obtained data on the polarization dynamics in polyvinylidene fluoride, a typical ferroe-lectric polymer, are analyzed during initial poling, short circuiting and polarization switching. Considering a two-component structure of the samples, namely, presence of ferroelectric and non-ferroelectric phases, it is shown that value and stability of the ferroelectric polarization significantly depend on conductivity and space charges. Application of a simple two-layer theoretical model with an explicit conductivity allowed ex-plaining such important features, as slow development and switching of the ferroelectric polarization and a partial back-switching of the already formed polarization after short-circuiting of the sample.

  8. Na+ Ion Conducting Hot-pressed Nano Composite Polymer Electrolytes

    OpenAIRE

    Angesh Chandra; Archan Chandra; Kiran Thakurb

    2012-01-01

    Synthesis, characterization and polymeric battery studies of Na+ ion conducting Nano- Composite Polymer Electrolyte (NCPE) membranes: (1-x) [75PEO: 25NaPO3]: x SiO2, where x = 0 - 15 wt. (%), has been reported. NCPE membranes have been casted using a novel hot-press technique in place of the traditional solution cast method. The dispersal of SiO2 in SPE host: (75PEO: 25NaPO3), a conductivity enhancement of an order of magnitude achieved in NCPE film: [93 (75PEO: 25NaPO3): 7 SiO2]. This has be...

  9. Electronically conductive polymer binder for lithium-ion battery electrode

    Science.gov (United States)

    Liu, Gao; Xun, Shidi; Battaglia, Vincent S; Zheng, Honghe

    2014-10-07

    A family of carboxylic acid group containing fluorene/fluorenon copolymers is disclosed as binders of silicon particles in the fabrication of negative electrodes for use with lithium ion batteries. These binders enable the use of silicon as an electrode material as they significantly improve the cycle-ability of silicon by preventing electrode degradation over time. In particular, these polymers, which become conductive on first charge, bind to the silicon particles of the electrode, are flexible so as to better accommodate the expansion and contraction of the electrode during charge/discharge, and being conductive promote the flow battery current.

  10. Self-assembly of CdTe nanocrystals at the water/oil interface by amphiphilic hyperbranched polymers

    International Nuclear Information System (INIS)

    A general strategy for realizing the self-assembly of aqueous CdTe nanocrystals (NCs) at the water/oil interface by means of an amphiphilic core-shell hyperbranched polymer has been proposed. Aqueous CdTe NCs were firstly transferred into the chloroform phase in the presence of palmityl chloride functionalized hyperbranched poly(amidoamine) (HPAMAM-PC), and then self-assembled at the water/chloroform interface by decreasing the pH value of the aqueous phase or introducing ?-CDs to the aqueous phase. The resulting CdTe/HPAMAM-PC self-assembly film was characterized by fluorescence microscopy, UV-vis, PL, TEM, EDS, FT-IR, DSC and TGA.

  11. Conductivity of oriented bis-azo polymer films

    DEFF Research Database (Denmark)

    Apitz, D.; Bertram, R.P.

    2006-01-01

    The conductivity properties of electro-optic photoaddressable, dense bis-ozo chromophore polymer films are investigated by using samples corona poled at various temperatures. A dielectric spectrometer is applied to measure the frequency dependence of the conductivity at different temperatures before and after heating the material to above the glass transition temperature. The results show that the orientation of the chromophores changes the charge-carrier mobility. Ionic conductivity dominates in a more disordered configuration of the material, while the competing process of hole hopping takes over as a transition to a liquid-crystalline phase occurs when the material is heated to much higher than the gloss transition temperature. Such micro-crystallization strongly enhances the conductivity.

  12. Better Proton-Conducting Polymers for Fuel-Cell Membranes

    Science.gov (United States)

    Narayan, Sri; Reddy, Prakash

    2012-01-01

    Polyoxyphenylene triazole sulfonic acid has been proposed as a basis for development of improved proton-conducting polymeric materials for solid-electrolyte membranes in hydrogen/air fuel cells. Heretofore, the proton-conducting membrane materials of choice have been exemplified by a family of perfluorosulfonic acid-based polymers (Nafion7 or equivalent). These materials are suitable for operation in the temperature of 75 to 85 C, but in order to reduce the sizes and/or increase the energy-conversion efficiencies of fuel-cell systems, it would be desirable to increase temperatures to as high as 120 C for transportation applications, and to as high as 180 C for stationary applications. However, at 120 C and at relative humidity values below 50 percent, the loss of water from perfluorosulfonic acid-based polymer membranes results in fuel-cell power densities too low to be of practical value. Therefore, membrane electrolyte materials that have usefully high proton conductivity in the temperature range of 180 C at low relative humidity and that do not rely on water for proton conduction at 180 C would be desirable. The proposed polyoxyphenylene triazole sulfonic acid-based materials have been conjectured to have these desirable properties. These materials would be free of volatile or mobile acid constituents. The generic molecular structure of these materials is intended to exploit the fact, demonstrated in previous research, that materials that contain ionizable acid and base groups covalently attached to thermally stable polymer backbones exhibit proton conduction even in the anhydrous state.

  13. Smart conducting polymer composites having zero temperature coefficient of resistance.

    Science.gov (United States)

    Chu, Kunmo; Lee, Sung-Chul; Lee, Sangeui; Kim, Dongearn; Moon, Changyoul; Park, Sung-Hoon

    2015-01-14

    Zero temperature coefficient of resistance (TCR) is essential for the precise control of temperature in heating element and sensor applications. Many studies have focused on developing zero-TCR systems with inorganic compounds; however, very few have dealt with developing zero-TCR systems with polymeric materials. Composite systems with a polymer matrix and a conducting filler show either a negative (NTC) or a positive temperature coefficient (PTC) of resistance, depending on several factors, e.g., the polymer nature and the filler shape. In this study, we developed a hybrid conducting zero-TCR composite having self-heating properties for thermal stability and reliable temperature control. The bi-layer composites consisted of a carbon nanotube (CNT)-based layer having an NTC of resistance and a carbon black (CB)-based layer having a PTC of resistance which was in direct contact with electrodes to stabilize the electrical resistance change during electric Joule heating. The composite showed nearly constant resistance values with less than 2% deviation of the normalized resistance until 200 °C. The CB layer worked both as a buffer and as a distributor layer against the current flow from an applied voltage. This behavior, which was confirmed both experimentally and theoretically, has been rarely reported for polymer-based composite systems. PMID:25351278

  14. Preparation and Characterization of Lithium Ion Conducting Solid Polymer Electrolytes from Biodegradable Polymers Starch And PVA

    Directory of Open Access Journals (Sweden)

    B. Chatterjee,

    2015-06-01

    Full Text Available Solid Polymer electrolyte films have been prepared from Starch-Poly vinyl alcohol (PVA blend a well acknowledged biodegradable material. Solution cast technique was employed for the preparation of solid polymer electrolyte films added with Lithium Bromide (LiBr salt. X-ray diffraction (XRD studies of the prepared films portrayed the evolution of an amorphous structure with increasing content of salt which is an important factor that leads to the augmentation of conductivity. Electrochemical impedance spectroscopic analysis revealed noticeable ionic conductivity ~ 5x 10-3 S/cm for 20 wt% of salt at ambient conditions. Ionic conductivity showed an increasing trend with salt content at ambient conditions. Transference number measurements confirmed the ionic nature of the prepared solid polymer electrolyte films. Dielectric studies revealed a sharp increase in the number of charge carriers which contributed to enhancement in conductivity. Low values of activation energy extracted from temperature dependent conductivity measurements could be favorable for device applications. For the composition with highest conductivity a temperature independent relaxation mechanism was confirmed by electric modulus scaling.

  15. Multifunctional and biomimicking electrochemical properties of conducting polymers

    Science.gov (United States)

    Otero, Toribio

    2005-06-01

    Electrochemical oxidation and reduction taking place in films of a conducting polymer involve: generation and annihilation of positive charges on the polymeric chains, conformational changes along the polymeric chains, coulombic repulsions and generation of free volume with interchange of ions and water molecules between the polymer and the solution. So, electric pulses, conformational changes, ionic and aqueous interchanges are involved, as it occurs during most of the biological functions. Those changes induce, simultaneously, different electrochemical properties: electrochemomechanical by swelling and shrinking processes, electrochromic by change of the molecular orbitals, charge storage by accumulation of positive or negative charges, electron-ion transduction between an electronic conductor and an electrolyte. All those properties mimic biological functions: muscles, mimicking skins, electric organs or nervous pulses. Some of the developed devices as sensing actuators (muscles), or smart membranes are presented.

  16. Photoelectron studies of electrochemical diffusion of conducting polymer/transparent conductive metal oxide film interfaces

    Science.gov (United States)

    Takemura, S.; Kato, H.; Nakajima, Y.

    1999-04-01

    X-ray photoelectron spectroscopy (XPS) investigations of conducting polymer polythiophene (PT)/indium tin oxide (ITO) and PT/SnO 2 interfaces have been conducted. Interfacial electrochemical diffusion of the metal oxide substrate species has been observed in both cases through electrochemical reduction process. XPS investigation has focused on the core-level energies and spectral profiles of the diffused substrate species into polymer matrix. A larger part of the diffused species is metal oxides in both cases determined by measuring chemical shifts of core-levels of In 3d 5/2 and Sn 3d 5/2. However, increase in lower binding energy components of In 3d 5/2 and Sn 3d 5/2 spectra of the diffused species indicates that the diffused species in polymer matrix are a mixture of metallic and oxide states of In and Sn. Furthermore, with regard to PT backbone-originated S 2p lines, a large splitting was observed indicating the large interaction between diffused metal oxides and sulfur sites of the polymer backbone.

  17. Mechanisms of proton conductance in polymer electrolyte membranes

    DEFF Research Database (Denmark)

    Eikerling, M.; Kornyshev, A. A.

    2001-01-01

    We provide a phenomenological description of proton conductance in polymer electrolyte membranes, based on contemporary views of proton transfer processes in condensed media and a model for heterogeneous polymer electrolyte membrane structure. The description combines the proton transfer events in a single pore with the total pore-network performance and, thereby, relates structural and kinetic characteristics of the membrane. The theory addresses specific experimentally studied issues such as the effect of the density of proton localization sites (equivalent weight) of the membrane material and the water content of the pores. The effect of the average distance between the sulfonate groups, which changes during membrane swelling, is analyzed in particular, and the factors which determine the temperature dependence of the macroscopic membrane conductance are disclosed. Numerical estimates of the specific membrane conductivity obtained from the theory agree very well with typical experimental data, thereby confirming the appropriateness of the theoretical concepts. Moreover, the versatility of the models offers a useful and transparent frame for combining the analysis of both experimental data and the results of molecular dynamics simulations.

  18. Synthesis and applications of electrically conducting polymer nanocomposites

    Science.gov (United States)

    Ku, Bon-Cheol

    This research focuses on the synthesis and applications of electrically conducting polymer nanocomposites through molecular self-assembly. Two different classes of polymers, polyaniline (PANI) and polyacetylenes have been synthesized by biomimetic catalysis and spontaneous polymerization method. For gas barrier materials, commercially available polymers, poly(allylamine hydrochloride) (PAH) and poly (acrylic acid) (PAA), have also been used and thermally cross-linked. The morphological, optical and electrical properties of amphiphilic polyacetylenes have been studied. Furthermore, barrier properties, permselectivity, pervaporation properties of polyacetylenes/aluminosilicate nanocomposites have been investigated. For processability and electrical properties of carbon nanotube and conducting polymers, substituted ionic polyacetylenes (SIPA) have been covalently incorporated onto single-walled carbon nanotubes (SWNT) using the "grafting-from" technique. In the first study, a nanocomposite film catalyst has been prepared by electrostatic layer-by-layer (ELBL) self-assembly of a polyelectrolyte and a biomimetic catalyst for synthesis of polyaniline. Poly(dimethyl diallylammonium chloride) (PDAC) and hematin have been used as polycation and counter anions, respectively. The absorption spectra by UV-vis-NIR spectroscopy showed that conductive form polyaniline was formed not only as a coating on the surface of the ELBL composites but was also formed in solution. Furthermore, it was found that the reaction rate was affected by pH and concentration of hematin in the multilayers. The feasibility of controlled desorption of hematin molecules from the LBL assembly was explored and demonstrated by changing the pH and hematin concentration. The polymerization rate of aniline in solution was enhanced with decreasing pH of the solutions due to increased desorption of hematin nanoparticles from the multilayers. These ELBL hematin assemblies demonstrated both a way to functionalize surfaces with conductive polyaniline and a potential method of reusability of the catalyst for improved cost effectiveness. For fabrication of multifunctional nanocomposite membranes, (P2EPy-R/Saponite) n on NafionRTM substrate was demonstrated by electrostatic layer-by layer assembly technique. (Abstract shortened by UMI.)

  19. Relaxation model of radiation-induced conductivity in polymers

    International Nuclear Information System (INIS)

    The paper suggests a relaxation model of radiation-induced conductivity (RIC) in polymers. According to the model, the transfer of charges generated in the polymer volume by ionizing radiation takes place with the participation of molecular relaxation processes. The mechanism of electron transport consists in the transfer of the charge directly between traps when they draw close to one another due to the rotation of macromolecule segments. The numerical solutions of the corresponding kinetic equations for different distribution functions Q(?) of the times of molecular relaxation and for different functions of the probability P(?, ?') of charge transfer in the 'overlapping' regions of the diffusion spheres of the segments are analyzed. The relaxation model provides an explanation of the non-Arrhenius behavior of the RIC temperature dependence, the power dependence of RIC on the dose rate with a power index in the interval 0.5-1.0, the appearance of maxima in the curves of the RIC temporal dependence and their irreversible character in the region of large dose rates (more than 1 Gy/s). The model can be used for interpreting polymer RIC in conditions of kinetic mobility of macromolecules

  20. Smart conducting polymer composites having zero temperature coefficient of resistance

    Science.gov (United States)

    Chu, Kunmo; Lee, Sung-Chul; Lee, Sangeui; Kim, Dongearn; Moon, Changyoul; Park, Sung-Hoon

    2014-12-01

    Zero temperature coefficient of resistance (TCR) is essential for the precise control of temperature in heating element and sensor applications. Many studies have focused on developing zero-TCR systems with inorganic compounds; however, very few have dealt with developing zero-TCR systems with polymeric materials. Composite systems with a polymer matrix and a conducting filler show either a negative (NTC) or a positive temperature coefficient (PTC) of resistance, depending on several factors, e.g., the polymer nature and the filler shape. In this study, we developed a hybrid conducting zero-TCR composite having self-heating properties for thermal stability and reliable temperature control. The bi-layer composites consisted of a carbon nanotube (CNT)-based layer having an NTC of resistance and a carbon black (CB)-based layer having a PTC of resistance which was in direct contact with electrodes to stabilize the electrical resistance change during electric Joule heating. The composite showed nearly constant resistance values with less than 2% deviation of the normalized resistance until 200 °C. The CB layer worked both as a buffer and as a distributor layer against the current flow from an applied voltage. This behavior, which was confirmed both experimentally and theoretically, has been rarely reported for polymer-based composite systems.Zero temperature coefficient of resistance (TCR) is essential for the precise control of temperature in heating element and sensor applications. Many studies have focused on developing zero-TCR systems with inorganic compounds; however, very few have dealt with developing zero-TCR systems with polymeric materials. Composite systems with a polymer matrix and a conducting filler show either a negative (NTC) or a positive temperature coefficient (PTC) of resistance, depending on several factors, e.g., the polymer nature and the filler shape. In this study, we developed a hybrid conducting zero-TCR composite having self-heating properties for thermal stability and reliable temperature control. The bi-layer composites consisted of a carbon nanotube (CNT)-based layer having an NTC of resistance and a carbon black (CB)-based layer having a PTC of resistance which was in direct contact with electrodes to stabilize the electrical resistance change during electric Joule heating. The composite showed nearly constant resistance values with less than 2% deviation of the normalized resistance until 200 °C. The CB layer worked both as a buffer and as a distributor layer against the current flow from an applied voltage. This behavior, which was confirmed both experimentally and theoretically, has been rarely reported for polymer-based composite systems. Electronic supplementary information (ESI) available: Normalized resistance as a function of increasing temperature for CNTs with different aspect ratios, other configurations of the bi-layered composite with the corresponding circuit diagrams, an SEM image of the CNT/PDMS composite with low resolution and dependence of DC conductivity on the number of three roll passes, numerically calculated normalized resistance of the bi-layer composite with different thickness ratios, streamlines and arrow plots of the current densities of the bi-layer composites with other configurations. See DOI: 10.1039/c4nr04489d

  1. Na+ Ion Conducting Hot-pressed Nano Composite Polymer Electrolytes

    Directory of Open Access Journals (Sweden)

    Angesh Chandra

    2012-03-01

    Full Text Available Synthesis, characterization and polymeric battery studies of Na+ ion conducting Nano- Composite Polymer Electrolyte (NCPE membranes: (1-x [75PEO: 25NaPO3]: x SiO2, where x = 0 - 15 wt. (%, has been reported. NCPE membranes have been casted using a novel hot-press technique in place of the traditional solution cast method. The dispersal of SiO2 in SPE host: (75PEO: 25NaPO3, a conductivity enhancement of an order of magnitude achieved in NCPE film: [93 (75PEO: 25NaPO3: 7 SiO2]. This has been referred to as Optimum Conducting Composition (OCC. Material characterizations have been done with the help of XRD, SEM and DSC techniques. The ion transport behaviour in hot-pressed NCPEs has been discussed on the basis of experimental measurements on some basic ionic parameters viz. conductivity (?, ionic mobility (?, mobile ion concentration (n and ionic transference number (t ion. The temperature dependent conductivity studies have been done to compute the activation energy (Ea values from the 'log s - 1/T' Arrhenius plots. The ion conducting solid state polymeric battery was fabricated and cell-potential discharge characteristics have been studied at different load conditions.

  2. Na+ Ion Conducting Hot-pressed Nano Composite Polymer Electrolytes

    Scientific Electronic Library Online (English)

    Angesh, Chandra; Archan, Chandra; Kiran, Thakurb.

    2012-03-01

    Full Text Available Synthesis, characterization and polymeric battery studies of Na+ ion conducting Nano- Composite Polymer Electrolyte (NCPE) membranes: (1-x) [75PEO: 25NaPO3]: x SiO2, where x = 0 - 15 wt. (%), has been reported. NCPE membranes have been casted using a novel hot-press technique in place of the traditi [...] onal solution cast method. The dispersal of SiO2 in SPE host: (75PEO: 25NaPO3), a conductivity enhancement of an order of magnitude achieved in NCPE film: [93 (75PEO: 25NaPO3): 7 SiO2]. This has been referred to as Optimum Conducting Composition (OCC). Material characterizations have been done with the help of XRD, SEM and DSC techniques. The ion transport behaviour in hot-pressed NCPEs has been discussed on the basis of experimental measurements on some basic ionic parameters viz. conductivity (?), ionic mobility (?), mobile ion concentration (n) and ionic transference number (t ion). The temperature dependent conductivity studies have been done to compute the activation energy (Ea) values from the 'log s - 1/T' Arrhenius plots. The ion conducting solid state polymeric battery was fabricated and cell-potential discharge characteristics have been studied at different load conditions.

  3. Effect of thermal treatment on electrical conductivities of poly pyrrole conducting polymers

    International Nuclear Information System (INIS)

    Some poly pyrrole free standing films or membranes doped with different electrolytes (aromatic sulphonated) were prepared from aqueous monomer solution in order to investigate the effect of thermal treatment on their electrical conductivity. It was found that the nature of count erion has the most important effect on determining the electrical conductivity and stability of conductivity when the polymer is exposed to high temperatures. However, mild heating can improve conductivity of poly pyrrole conducting polymers. In order to carry out thermal effect studies on conductivity and measure the thermal stability of the P Py film, a variety of anions were examined. It was found that when poly pyrrole is being doped with aromatic sulphonates (mainly benzene or naphthalene sulphonates) as counterions, it produces flexible and smooth films that can be readily detached from working electrode as membrane and they have good mechanical properties. Other counterions such as inorganic s (e. g., Cl-, So42-), aliphatic surfactants (e. g., Ds), and polymeric s (Pvs) produce films that are either impossible to remove from working electrode, or give brittle, and rough films

  4. Electrofragmentation modeling of conductive coatings on polymer substrates

    Science.gov (United States)

    Leterrier, Yves; Pinyol, Albert; Rougier, Luc; Waller, Judith H.; Mânson, Jan-Anders E.

    2009-12-01

    Damage occurring under tensile loading and the resulting increase in electrical resistance of tin-doped indium oxide and amorphous graphite coatings on various polymer substrates are investigated, using an electrofragmentation method in situ in an optical microscope. The electrical resistance is modeled as a function of damage state assuming that the resistance of coating cracks is proportional to their opening, and that there exists a conducting path of constant thickness at the coating/substrate interface across the crack. The model reproduces the experimental data with good accuracy apart from the damage initiation and saturation stages where it underestimates the measured coating resistance. This is due to the presence of stable cracks of finite length in the initiation stage and delamination in the saturation stage. Impedance spectroscopy measurements confirm the purely resistive nature of the conducting path, whose resistivity is found to be three to four orders of magnitude higher than that of the uncracked coating.

  5. Electronically conductive polymer binder for lithium-ion battery electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gao; Battaglia, Vincent S.; Park, Sang -Jae

    2015-10-06

    A family of carboxylic acid groups containing fluorene/fluorenon copolymers is disclosed as binders of silicon particles in the fabrication of negative electrodes for use with lithium ion batteries. Triethyleneoxide side chains provide improved adhesion to materials such as, graphite, silicon, silicon alloy, tin, tin alloy. These binders enable the use of silicon as an electrode material as they significantly improve the cycle-ability of silicon by preventing electrode degradation over time. In particular, these polymers, which become conductive on first charge, bind to the silicon particles of the electrode, are flexible so as to better accommodate the expansion and contraction of the electrode during charge/discharge, and being conductive promote the flow battery current.

  6. Multiscale Modeling of Thermal Conductivity of Polymer/Carbon Nanocomposites

    Science.gov (United States)

    Clancy, Thomas C.; Frankland, Sarah-Jane V.; Hinkley, Jeffrey A.; Gates, Thomas S.

    2010-01-01

    Molecular dynamics simulation was used to estimate the interfacial thermal (Kapitza) resistance between nanoparticles and amorphous and crystalline polymer matrices. Bulk thermal conductivities of the nanocomposites were then estimated using an established effective medium approach. To study functionalization, oligomeric ethylene-vinyl alcohol copolymers were chemically bonded to a single wall carbon nanotube. The results, in a poly(ethylene-vinyl acetate) matrix, are similar to those obtained previously for grafted linear hydrocarbon chains. To study the effect of noncovalent functionalization, two types of polyethylene matrices. -- aligned (extended-chain crystalline) vs. amorphous (random coils) were modeled. Both matrices produced the same interfacial thermal resistance values. Finally, functionalization of edges and faces of plate-like graphite nanoparticles was found to be only modestly effective in reducing the interfacial thermal resistance and improving the composite thermal conductivity

  7. Electronically conductive polymer binder for lithium-ion battery electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gao; Xun, Shidi; Battaglia, Vincent S.; Zheng, Honghe; Wu, Mingyan

    2015-07-07

    A family of carboxylic acid groups containing fluorene/fluorenon copolymers is disclosed as binders of silicon particles in the fabrication of negative electrodes for use with lithium ion batteries. Triethyleneoxide side chains provide improved adhesion to materials such as, graphite, silicon, silicon alloy, tin, tin alloy. These binders enable the use of silicon as an electrode material as they significantly improve the cycle-ability of silicon by preventing electrode degradation over time. In particular, these polymers, which become conductive on first charge, bind to the silicon particles of the electrode, are flexible so as to better accommodate the expansion and contraction of the electrode during charge/discharge, and being conductive promote the flow battery current.

  8. Electrical Conductivity in Polymer Blends/ Multiwall Carbon Nanotubes

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNT) based polymer composites have emerged as the future multifunctional materials in view of its exceptional mechanical, thermal and electrical properties. One of the major interests is to develop conductive polymer composites preferably at low concentration of CNT utilizing their high aspect ratio (L/D) for numerous applications, which include antistatic devices, capacitors and materials for EMI shielding. In this context, polymer blends have emerged as a potential candidate in lowering the percolation thresholds further by the utilization of 'double-percolation' which arises from the synergistic improvements in blend properties associated with the co-continuous morphology. Due to strong inter-tube van der Waals' forces, they often tend to aggregate and uniform dispersion remains a challenge. To overcome this challenge, we exploited sodium salt of 6-aminohexanoic acid (Na-AHA) which was able to assist in debundlling the multiwall carbon nanotubes (MWNT) through 'cation-?' interactions during melt-mixing leading to percolative 'network-like' structure of MWNT within polyamide6 (PA6) phase in co-continuous PA6/acrylonitrile butadiene styrene (ABS) blends. The composite exhibited low electrical percolation thresholds of 0.25 wt% of MWNT, the lowest reported value in this system so far. Retention of 'network-like structure' in the solid state with significant refinement was observed even at lower MWNT concentration in presence Na-AHA, which was assessed through AC electrical conductivity measurements. Reactive coupling was found to be a dominant factor besides 'cation-?' interactions in achieving low electrical percolation in PA6/ABS+MWNT composites.

  9. Drastic modification of the piezoresistive behavior of polymer nanocomposites by using conductive polymer coatings

    KAUST Repository

    Ventura, Isaac Aguilar

    2015-07-21

    We obtained highly conductive nanocomposites by adding conductive polymer poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS)-coated carbon nanotubes (CNTs) to pristine insulating Polycarbonate. Because the PEDOT/PSS ensures efficient charge transfer both along and between the CNTs, we could attribute the improvement in electrical conductivity to coating. In addition to improving the electrical conductivity, the coating also modified the piezoresistive behavior of the nanocomposites compared to the material with pristine uncoated CNTs: whereas CNT/Polycarbonate samples exhibited a very strong piezoresistive effect, PEDOT/PSS-coated MWCNT/Polycarbonate samples exhibited very little piezoresistivity. We studied this change in piezoresistive behavior in detail by investigating various configurations of filler content. We investigated how this observation could be explained by changes in the microstructure and in the conduction mechanism in the interfacial regions between the nanofillers. Our study suggests that tailoring the piezoresistive response to specific application requirements is possible.

  10. All conducting polymer electrodes for asymmetric solid-state supercapacitors

    KAUST Repository

    Kurra, Narendra

    2015-01-01

    In this study, we report the fabrication of solid-state asymmetric supercapacitors (ASCs) based on conducting polymer electrodes on a plastic substrate. Nanostructured conducting polymers of poly(3,4-ethylenedioxythiophene), PEDOT, and polyaniline (PANI) are deposited electrochemically over Au-coated polyethylene naphthalate (PEN) plastic substrates. Due to the electron donating nature of the oxygen groups in the PEDOT, reduction potentials are higher, allowing it to be used as a negative electrode material. In addition, the high stability of PEDOT in its oxidised state makes it capable to exhibit electrochemical activity in a wide potential window. This can qualify PEDOT to be used as a negative electrode in fabricating asymmetric solid state supercapacitors with PANI as a positive electrode while employing polyvinyl alcohol (PVA)/H2SO4 gel electrolyte. The ASCs exhibit a maximum power density of 2.8 W cm-3 at an energy density of 9 mW h cm-3, which is superior to the carbonaceous and metal oxide based ASC solid state devices. Furthermore, the tandem configuration of asymmetric supercapacitors is shown to be capable of powering a red light emitting diode for about 1 minute after charging for 10 seconds. © The Royal Society of Chemistry 2015.

  11. All conducting polymer electrodes for asymmetric solid-state supercapacitors

    KAUST Repository

    Kurra, Narendra

    2015-02-16

    In this study, we report the fabrication of solid-state asymmetric supercapacitors (ASCs) based on conducting polymer electrodes on a plastic substrate. Nanostructured conducting polymers of poly(3,4-ethylenedioxythiophene), PEDOT, and polyaniline (PANI) are deposited electrochemically over Au-coated polyethylene naphthalate (PEN) plastic substrates. Due to the electron donating nature of the oxygen groups in the PEDOT, reduction potentials are higher, allowing it to be used as a negative electrode material. In addition, the high stability of PEDOT in its oxidised state makes it capable to exhibit electrochemical activity in a wide potential window. This can qualify PEDOT to be used as a negative electrode in fabricating asymmetric solid state supercapacitors with PANI as a positive electrode while employing polyvinyl alcohol (PVA)/H2SO4 gel electrolyte. The ASCs exhibit a maximum power density of 2.8 W cm?3 at an energy density of 9 mW h cm?3, which is superior to the carbonaceous and metal oxide based ASC solid state devices. Furthermore, the tandem configuration of asymmetric supercapacitors is shown to be capable of powering a red light emitting diode for about 1 minute after charging for 10 seconds.

  12. Abnormal temperature dependence of mobility in conjugated polymer / nanocrystal composite: experiment and theory

    OpenAIRE

    Zhang, Yating; Yao, Jianquan; Kwok, Hoi Sing

    2013-01-01

    Instead of normal non-Arrhenius relationship, the carrier mobility $ln({\\mu})$ v.s. $1/T^2$ showed abnormal dependence in an MEH-PPV / InP nanocrystal composite system that a critical temperature $(T_c)$ behavior is prominent in temperature range of 233 K to 333 K. Here, in the model of variable range hopping theory, an analytical model is developed within a Gaussian trap distribution, which is successfully implemented on that phenomenon. The results show that Tc becomes the...

  13. Conductivity of microfibrillar polymer-polymer composites with CNT-loaded microfibrils or compatibilizer: A comparative study

    OpenAIRE

    S. Fakirov; S. M. Panamoottil; P. Potschke; R. J. T. Lin; Bhattacharyya, D.

    2013-01-01

    Conductive polymer composites have wide ranging applications, but when they are produced by conventional melt blending, high conductive filler loadings are normally required, hindering their processability and reducing mechanical properties. In this study, two types of polymer-polymer composites were studied: i) microfibrillar composites (MFC) of polypropylene (PP) and 5 wt% carbon nanotube (CNT) loaded poly(butylene terephthalate) (PBT) as reinforcement, and ii) maleic anhydride-grafted poly...

  14. Moving beyond mass-based parameters for conductivity analysis of sulfonated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Seung [Los Alamos National Laboratory; Pivovar, Bryan [NREL

    2009-01-01

    Proton conductivity of polymer electrolytes is critical for fuel cells and has therefore been studied in significant detail. The conductivity of sulfonated polymers has been linked to material characteristics in order to elucidate trends. Mass based measurements based on water uptake and ion exchange capacity are two of the most common material characteristics used to make comparisons between polymer electrolytes, but have significant limitations when correlated to proton conductivity. These limitations arise in part because different polymers can have significantly different densities and conduction happens over length scales more appropriately represented by volume measurements rather than mass. Herein, we establish and review volume related parameters that can be used to compare proton conductivity of different polymer electrolytes. Morphological effects on proton conductivity are also considered. Finally, the impact of these phenomena on designing next generation sulfonated polymers for polymer electrolyte membrane fuel cells is discussed.

  15. Thermal Conductivity of Carbon Nanotubes and their Polymer Nanocomposites: A Review

    OpenAIRE

    Han, Zhidong; Fina, Alberto

    2011-01-01

    Thermally conductive polymer composites offer new possibilities for replacing metal parts in several applications, including power electronics, electric motors and generators, heat exchangers, etc., thanks to the polymer advantages such as light weight, corrosion resistance and ease of processing. Current interest to improve the thermal conductivity of polymers is focused on the selective addition of nanofillers with high thermal conductivity. Unusually high thermal conductivity makes carbon ...

  16. Conductivity enhancement of conjugated polymer after HCl-methanol treatment

    International Nuclear Information System (INIS)

    Polymer conductivity is key factor to improve the performance of the electronic and photonic devices. Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) films were soaked into 0.03, 0.14, 0.41, and 1.13 M concentrations of HCl-methanol solution for 10, 20, 30, 40, 50, 60, and 70 min. The resulting films were investigated using Fourier transform infrared (FTIR) spectrometry, conductivity measurements, and field emission scanning electron microscopy. The characteristic FTIR absorption peaks of poly(4-styrenesulfonate) (PSS) of the films decreased as the soaking time increased. While PSS absorption peaks appeared in the HCl-methanol soaking solution and increased with the soaking time. The conductivity of PEDOT:PSS film was approximately 1.20 x 10-6 S/cm before soaking in the HCl-methanol solution. The conductivity of PEDOT:PSS was enhanced nearly three orders of magnitude after soaking the films into the HCl-methanol solvent. The surface of PEDOT:PSS film was initially very smooth. However, numerous humps appeared on the surface of the films after soaking PEDOT:PSS film into the HCl-methanol solution for 10, 20, and 30 min. The number of humps was reduced and disappeared thereafter.

  17. Conductive paper from lignocellulose wood microfibers coated with a nanocomposite of carbon nanotubes and conductive polymers.

    Science.gov (United States)

    Agarwal, Mangilal; Xing, Qi; Shim, Bong Sup; Kotov, Nicholas; Varahramyan, Kody; Lvov, Yuri

    2009-05-27

    Composite nanocoating of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) and aqueous dispersion of carbon nanotubes (CNT-PSS) on lignocellulose wood microfibers has been developed to make conductive microfibers and paper sheets. To construct the multilayers on wood microfibers, cationic poly(ethyleneimine) (PEI) has been used in alternate deposition with anionic conductive PEDOT-PSS and solubilized CNT-PSS. Using a Keithley microprobe measurement system, current-voltage measurements have been carried out on single composite microfibers after deposition of each layer to optimize the electrical properties of the coated microfibers. The conductivity of the resultant wood microfibers was in the range of 10(-2)-2 S cm(-1) depending on the architecture of the coated layer. Further, the conductivity of the coated wood microfibers increased up to 20 S cm(-1) by sandwiching multilayers of conductive co-polymer PEDOT-PSS with CNT-PSS through a polycation (PEI) interlayer. Moreover, paper hand sheets were manufactured from these coated wood microfibers with conductivity ranging from 1 to 20 S cm(-1). A paper composite structure consisting of conductive/dielectric/conductive layers that acts as a capacitor has also been fabricated and is reported. PMID:19423933

  18. Conductive paper from lignocellulose wood microfibers coated with a nanocomposite of carbon nanotubes and conductive polymers

    International Nuclear Information System (INIS)

    Composite nanocoating of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) and aqueous dispersion of carbon nanotubes (CNT-PSS) on lignocellulose wood microfibers has been developed to make conductive microfibers and paper sheets. To construct the multilayers on wood microfibers, cationic poly(ethyleneimine) (PEI) has been used in alternate deposition with anionic conductive PEDOT-PSS and solubilized CNT-PSS. Using a Keithley microprobe measurement system, current-voltage measurements have been carried out on single composite microfibers after deposition of each layer to optimize the electrical properties of the coated microfibers. The conductivity of the resultant wood microfibers was in the range of 10-2-2 S cm-1 depending on the architecture of the coated layer. Further, the conductivity of the coated wood microfibers increased up to 20 S cm-1 by sandwiching multilayers of conductive co-polymer PEDOT-PSS with CNT-PSS through a polycation (PEI) interlayer. Moreover, paper hand sheets were manufactured from these coated wood microfibers with conductivity ranging from 1 to 20 S cm-1. A paper composite structure consisting of conductive/dielectric/conductive layers that acts as a capacitor has also been fabricated and is reported.

  19. Encapsulation of novel fluorescent nanocrystals (quantum dots) with a nanocomposite polymer and their assessment by in-vitro and in-vivo studies

    Science.gov (United States)

    Iga, Arthur M.

    Advance in nanotechnology has led to the development of novel fluorescent probes called quantum dots which are being exploited for potential new methods of early cancer detection spread and therapeutic management. Concerns regarding the release of potentially toxic inorganic core atoms into their surrounding environment and possession of hydrophobic surfaces are hindering the development of quantum dots. In order to abrogate their toxicity and solubilise the nanocrystals in aqueous solution a novel polyhedral oligomeric silsesquioxanes (POSS) poly(carbonate-urea)urethane (PCU), a silica nanocomposite (NC) polymer has been used to coat them. Physical and chemical analysis of the coated quantum dots with UV-Visible spectrometry, Photoluminescence, transmission electron microscopy, X-ray microanalysis and diffraction. Atomic force microscope and FTIR Spectrophotometry has enabled us ascertain the characteristics of these unique nanocrystals. The biocompatibility of the nanocomposite coated quantum dots (NCCQD) was assessed by using Alamar blue metabolic assay, Pico green assay and by measuring lactate dehydrogenase release on endothelial cell damage. Potential interference of NCCQD with a rat's normal physiology and systemic tissue distribution were assessed in an in-vivo animal model. Results demonstrated that the nanocrystals retained their unique optical properties, had a mean hydrodynamic diameter of 10.5 nm, excellent monodispersivity, large absorption spectrum with a narrow emission band at 790 nm and were highly photostable after polymer coating. NCCQD were compatible with endothelial cells as viable cells were demonstrated to be present after 14 days of growing cells in cell culture medium exposed to NCCQD at concentrations of 2.25 X 10"2 nM. There was no significant disturbance in the physiological parameters on injecting the NCCQD in an in-vivo rat model over a 2 hour period. NCCQD were seen to be deposited in the spleen and thymus as they are reticuloendothelial organs. In conclusion polymer encapsulated CdTe nanocrystals have tremendous potential to be exploited as a medical device in in-vivo imaging.

  20. Refractive Indices of Specific Nonconjugated Conductive Polymers: Organic Nanometallic Systems

    Science.gov (United States)

    Dubey, Prashant; Shrivastava, Sapana; Thakur, Mrinal

    2011-03-01

    Exceptionally large quadratic electro-optic effect and two-photon absorption coefficients have been recently reported for nonconjugated conductive polymers after doping. These polymers include: cis- and trans- polyisoprene, poly(? -pinene) and others. The large optical nonlinearities observed in these materials have been attributed to the nanometallic state with subnanometer dimensions that is formed upon doping and charge-transfer. Measurement and calculation of linear refractive indices of these novel nonlinear optical systems before and after doping are important. Linear absorption coefficients (UV-Visible) of trans-1,4-polyisoprene have been measured for different doping levels of iodine. Refractive indices have been calculated using Kramers-Kronig transformation of absorption data for different doping levels. Numerical integration using MATLAB software was used for these calculations. Refractive indices at specific wavelengths have been determined by measuring reflectivity at normal incidence. The calculated and measured values of refractive indices have been compared. Results on calculations and measurements on these novel systems will be discussed.

  1. Electrically Conductive Metal Polymer Nanocomposites for Electronics Applications

    Science.gov (United States)

    Karttunen, Mikko; Ruuskanen, Pekka; Pitkänen, Ville; Albers, Willem M.

    2008-07-01

    An electrically conductive nanocomposite composed of thermoplastic elastomer and nanosized silver particles was developed. Nanosized silver particles were produced by the liquid flame spraying method. Nanocomposites were produced employing a batch mixing process in the melt state. The percolation curve and the minimum resistivity as a function of silver content were defined. A plasticized styrene block-copolymer was used as the matrix polymer. The results showed that the agglomeration of the silver particles has a major influence on the percolation threshold and the resistivity of the compound. With slightly agglomerated silver particles a percolation threshold with a silver content of 13 16 vol.% was achieved. The corresponding resistivity was 2.0 × 10-1 ? cm. With heavily agglomerated particles the resistivity is high (2.9 × 103 ? cm), even with a silver content of 20 vol.%. With a low primary silver particle size (under 100 nm), the resistivity of the compound was high (5.6 × 105 ? cm).

  2. Conductive Polymer Porous Film with Tunable Wettability and Adhesion

    Directory of Open Access Journals (Sweden)

    Yuqi Teng

    2015-04-01

    Full Text Available A conductive polymer porous film with tunable wettability and adhesion was fabricated by the chloroform solution of poly(3-hexylthiophene (P3HT and [6,6]-phenyl-C61-butyricacid-methyl-ester (PCBM via the freeze drying method. The porous film could be obtained from the solution of 0.8 wt%, whose pore diameters ranged from 50 nm to 500 nm. The hydrophobic porous surface with a water contact angle (CA of 144.7° could be transferred into a hydrophilic surface with CA of 25° by applying a voltage. The water adhesive force on the porous film increased with the increase of the external voltage. The electro-controllable wettability and adhesion of the porous film have potential application in manipulating liquid collection and transportation.

  3. Porous palladium coated conducting polymer nanoparticles for ultrasensitive hydrogen sensors.

    Science.gov (United States)

    Lee, Jun Seop; Kim, Sung Gun; Cho, Sunghun; Jang, Jyongsik

    2015-12-28

    Hydrogen, a clean-burning fuel, is of key importance to various industrial applications, including fuel cells and in the aerospace and automotive industries. However, hydrogen gas is odorless, colorless, and highly flammable; thus appropriate safety protocol implementation and monitoring are essential. Highly sensitive hydrogen leak detection and surveillance sensor systems are needed; additionally, the ability to maintain uniformity through repetitive hydrogen sensing is becoming increasingly important. In this report, we detail the fabrication of porous palladium coated conducting polymer (3-carboxylate polypyrrole) nanoparticles (Pd@CPPys) to detect hydrogen gas. The Pd@CPPys are produced by means of facile alkyl functionalization and chemical reduction of a pristine 3-carboxylate polypyrrole nanoparticle-contained palladium precursor (PdCl2) solution. The resulting Pd@CPPy-based sensor electrode exhibits ultrahigh sensitivity (0.1 ppm) and stability toward hydrogen gas at room temperature due to the palladium sensing layer. PMID:26598964

  4. Functionalised inherently conducting polymers as low biofouling materials.

    Science.gov (United States)

    Zhang, Binbin; Nagle, Alex R; Wallace, Gordon G; Hanks, Timothy W; Molino, Paul J

    2015-01-01

    Diatoms are a major component of microbial biofouling layers that develop on man-made surfaces placed in aquatic environments, resulting in significant economic and environmental impacts. This paper describes surface functionalisation of the inherently conducting polymers (ICPs) polypyrrole (PPy) and polyaniline (PANI) with poly(ethylene glycol) (PEG) and their efficacy as fouling resistant materials. Their ability to resist interactions with the model protein bovine serum albumin (BSA) was tested using a quartz crystal microbalance with dissipation monitoring (QCM-D). The capacity of the ICP-PEG materials to prevent settlement and colonisation of the fouling diatom Amphora coffeaeformis (Cleve) was also assayed. Variations were demonstrated in the dopants used during ICP polymerisation, along with the PEG molecular weight, and the ICP-PEG reaction conditions, all playing a role in guiding the eventual fouling resistant properties of the materials. Optimised ICP-PEG materials resulted in a significant reduction in BSA adsorption, and > 98% reduction in diatom adhesion. PMID:26218247

  5. Quantum soliton conductivity in polymers: a field theory approach

    International Nuclear Information System (INIS)

    Full text: The discovery of a tremendous increase in the electrical conductivity of polyacetylene, the simplest linear conjugated polymer, when doped with either halogens or alkalis, was a breakthrough of far reaching consequences in physics and chemistry. The fact that the trans-isomer occurs in two degenerate species opens the possibility of occurrence of soliton defects interconnecting them. Indeed, quantum solitons or polarons are supposed to play a crucial role in the electric conductivity of polyacetylene, in the intermediate doping regime. In this work, we present an exact fully quantized calculation of the quantum soliton conductivity in polyacetylene and show that it vanishes exactly. This strongly suggests that dynamic solitons are not the charge carriers in polyacetylene. Rather, polarons, which are basically soliton-anti soliton bound states should be responsible for the transport of charge in the intermediate doping regime of polyacetylene. This result is obtained by applying a general method of soliton quantization, based on order-disorder duality, to a Z(2)-symmetric complex extension of the TLM (Takayama, Lin-Liu and Maki) dimerization effective field theory. We show that, in this theory, polyacetylene solitons are sine-Gordon solitons in the phase of the complex field. (author)

  6. Understanding hopping transport and thermoelectric properties of conducting polymers

    Science.gov (United States)

    Ihnatsenka, S.; Crispin, X.; Zozoulenko, I. V.

    2015-07-01

    We calculate the conductivity ? and the Seebeck coefficient S for the phonon-assisted hopping transport in conducting polymers poly(3,4-ethylenedioxythiophene) or PEDOT, experimentally studied by Bubnova et al. [J. Am. Chem. Soc. 134, 16456 (2012)], 10.1021/ja305188r. We use the Monte Carlo technique as well as the semianalytical approach based on the transport energy concept. We demonstrate that both approaches show a good qualitative agreement for the concentration dependence of ? and S . At the same time, we find that the semianalytical approach is not in a position to describe the temperature dependence of the conductivity. We find that both Gaussian and exponential density of states (DOS) reproduce rather well the experimental data for the concentration dependence of ? and S giving similar fitting parameters of the theory. The obtained parameters correspond to a hopping model of localized quasiparticles extending over 2-3 monomer units with typical jumps over a distance of 3-4 units. The energetic disorder (broadening of the DOS) is estimated to be 0.1 eV. Using the Monte Carlo calculation we reproduce the activation behavior of the conductivity with the calculated activation energy close to the experimentally observed one. We find that for a low carrier concentration a number of free carriers contributing to the transport deviates strongly from the measured oxidation level. Possible reasons for this behavior are discussed. We also study the effect of the dimensionality on the charge transport by calculating the Seebeck coefficient and the conductivity for the cases of three-, two-, and one-dimensional motion.

  7. Structure-conductivity studies in polymer electrolytes containing multivalent cations

    International Nuclear Information System (INIS)

    Understanding the structure - conductivity relationship is of paramount importance for the development of polymer electrolytes. The present studies present the techniques found useful in the elucidation of structure - conductivity relationship in PEOn:ZnBr2 (n = 8, 1000, 2000, 3000, 4000 and 5000) and PEOn:FeBrx (n= 8, 20 and 50; x = 2 and 3). Local structural studies have been undertaken using X-ray absorption fine structures (XAFS) which includes extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). EXAFS provides interatomic distance and coordination numbers of the nearest neighbours and results from the EXAFS studies showed that high conductivity is associated with stretched M - O interatomic distance. In the studies on ultra dilute Zn samples it was found that the cation is highly solvated by the heteroatom forming a tightly bound environment which inhibits local segmental motion thus impeding ion migration. XANES studies on the PEO and modified PEO complexes of NiBr2 revealed the sensitivity of XANES to the structural differences. XANES on Zn and Fe samples also revealed the sensitivity to changes in interatomic distances reflected in shifts of the white line. The complementary nature of EXAFS and XANES was reflected in the studies conducted. Morphological studies were undertaken employing differential scanning calorimetry (DSC), variable temperature polarising microscopy (VTPM) and atomic force microscopy (AFM). DSC evidences helped to explain the texture of the iron samples during the drying process, and showed transitions between low melting, PEO and high melting spherulites, and VTPM is able to visualise the spherulites present in the samples. AFM has successfully imaged the as cast PEO8:FeBr2 sample and the surface effect causing extra resistance in the impedance spectra could be seen. Conductivity studies were carried out using a.c. impedance spectra. Fe(ll) samples exhibit the typical semicircle-spike plot but the Fe(lll) samples displayed an extra semicircle before the spike reflecting a surface effect. This is also manifested in the Arrhenius plots of the same samples where a dip was shown at 100 deg C. From the conductivity studies on the iron systems it was found that for the dry samples the optimum conductivity was observed in PEO8:FeBrx irrespective of the valence state of the cation. For the air-cast samples the optimum conductivity composition depends on the valence state and were shown to be at more dilute compositions. (author)

  8. A Route for Polymer Nanocomposites with Engineered Electrical Conductivity and Percolation Threshold

    OpenAIRE

    Lawrence T. Drzal; Hiroyuki Fukushima; Kyriaki Kalaitzidou

    2010-01-01

    Polymer nanocomposites with engineered electrical properties can be made by tuning the fabrication method, processing conditions and filler’s geometric and physical properties. This work focuses on investigating the effect of filler’s geometry (aspect ratio and shape), intrinsic electrical conductivity, alignment and dispersion within the polymer, and polymer crystallinity, on the percolation threshold and electrical conductivity of polypropylene based nanocomposites. The conductive reinforce...

  9. A New Conducting Polymer Electrode for Organic Electroluminescence Devices

    International Nuclear Information System (INIS)

    Conducting polymer polydimethylsiloxane (PDMS) is studied for the high performance electrode of organic electroluminescence devices. A method to prepare the electrode consisting of a SiC thin film and PDMS is investigated. By using ultra thin SiC films with different thicknesses, the organic electroluminescence devices are obtained in an ultra vacuum system with the model device PDMS/SiC/PPV/Alq3, where PPV is poly para-phenylene vinylene and Alq3 is tris(8-hydroxyquinoline) aluminium. The capacitance-voltage (C - V), capacitance-frequency (C - F), current-voltage (I - V), radiation intensity-voltage (R - V) and luminance efficiency-voltage (E - V) measurements are systematically studied to investigate the conductivity, Fermi alignment and devices properties in organic semiconductors. Scanning Kelvin probe measurement shows that the work function ofPDMS/SiC anode with a 2.5-nm SiC over layer can be increased by as much as 0.28 eV, compared to the conventional ITO anode. The result is attributed to the charge transfer effect and ohmic contacts at the interface. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. Soft capacitor fibers using conductive polymers for electronic textiles

    International Nuclear Information System (INIS)

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its cross section the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using the fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometers of fibers can be obtained from a single preform with fiber diameters ranging between 500 and 1000 µm. A typical measured capacitance of our fibers is 60–100 nF m?1 and it is independent of the fiber diameter. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 k? m L?1, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, the absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage

  11. Soft capacitor fibers using conductive polymers for electronic textiles

    CERN Document Server

    Gu, Jian Feng; Skorobogatiy, Maksim

    2010-01-01

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its crossection the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometres of fibers can be obtained from a single preform with fiber diameters ranging between 500um -1000um. A typical measured capacitance of our fibers is 60-100 nF/m and it is independent of the fiber diameter. For comparison, a coaxial cable of the comparable dimensions would have only ~0.06nF/m capacitance. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kOhm/L, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials...

  12. Crystalline polymers with exceptionally low thermal conductivity studied using molecular dynamics

    Science.gov (United States)

    Robbins, Andrew B.; Minnich, Austin J.

    2015-11-01

    Semi-crystalline polymers have been shown to have greatly increased thermal conductivity compared to amorphous bulk polymers due to effective heat conduction along the covalent bonds of the backbone. However, the mechanisms governing the intrinsic thermal conductivity of polymers remain largely unexplored as thermal transport has been studied in relatively few polymers. Here, we use molecular dynamics simulations to study heat transport in polynorbornene, a polymer that can be synthesized in semi-crystalline form using solution processing. We find that even perfectly crystalline polynorbornene has an exceptionally low thermal conductivity near the amorphous limit due to extremely strong anharmonic scattering. Our calculations show that this scattering is sufficiently strong to prevent the formation of propagating phonons, with heat being instead carried by non-propagating, delocalized vibrational modes known as diffusons. Our results demonstrate a mechanism for achieving intrinsically low thermal conductivity even in crystalline polymers that may be useful for organic thermoelectrics.

  13. In situ synthesis and characterization of silver/polymer nanocomposites by thermal cationic polymerization processes at room temperature: initiating systems based on organosilanes and starch nanocrystals.

    Science.gov (United States)

    Tehfe, Mohamad-Ali; Jamois, Romain; Cousin, Patrice; Elkoun, Saïd; Robert, Mathieu

    2015-04-14

    New methods for the preparation of silver nanoparticles/polymer nanocomposite materials by thermal cationic polymerization of ?-caprolactone (?-CL) or ?-pinene oxide (?-PO) at room temperature (RT) and under air were developed. The new initiating systems were based on silanes (Si), starch nanocrystals (StN) and metal salts. Excellent polymerization profiles were revealed. It was shown that silver nanoparticles (Ag(0) NPs) were in situ formed and that the addition of StN improves the polymerization efficiency. The as-synthesized nanocomposite materials contained spherical nanoparticles homogeneously dispersed in the polymer matrices. Polymers and nanoparticles were characterized by gel permeation chromatography (GPC), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy. A coherent picture of the involved chemical mechanisms is presented. PMID:25793620

  14. A conducting polymer artificial muscle with 12% linear strain

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld; Sommer-Larsen, P.; Skaarup, Steen; Benslimane, M.

    2003-01-01

    The efforts given to optimize the linear strain response of polypyrrole (PPy) doped with alkyl benzene sulfonate (ABS) as these systems show particularly good chemical stability in aqueous systems and little toxicity are presented. The aims of the optimization is to obtain maximum length changes in a freely suspended polymer foil in response to a potential change and it includes attention to the composition of the polymer, to the synthesis conditions, and involves microstructuring of the polymer...

  15. Influence of Conducting Polymers Based on Carboxylated Polyaniline on In Vitro CaCO3 Crystallization

    OpenAIRE

    Neira-Carrillo, Andronico; Acevedo, Diego F.; Miras, Maria C.; Barbero, Cesar A.; Gebauer, Denis; Cölfen, Helmut; Arias, Jose L.

    2008-01-01

    Conducting polymers are interesting materials of technological applications, while the use of polymers as additives controlling crystal nucleation and growth is a fast growing research field. In the present article, we make a first step in combining both topics and report the effect of conducting polymer derivatives, which are based on carboxylated polyanilines (c-PANIs), on in vitro CaCO3 crystallization by the Kitano and gas diffusion method. This is the first example of the mineralization ...

  16. Electrochemical study of charge transfer in conducting polymers

    Scientific Electronic Library Online (English)

    J.M., Pernaut; L.C., Soares; J.C., Belchior.

    Full Text Available Aspectos cinético e termodinâmico da transferência de carga em polímeros condutores foram investigados. Um modelo de difusão restrita foi impregado para interpretar os dados obtidos por cronopotenciometria com pulso. Em filmes de poli 3-metiltiofeno, o coeficiente de difusão aparente diminuiu em fun [...] ção da espessura do filme mas ficou constante com a concentração eletrolítica. Em filmes finos, usando-se voltametria cíclica, caracterizou-se mudanças termodinâmicas, como em particular, a deconvolução das duas transferências eletrônicas envolvidas no processo. Usando-se um modelo nernstiano incluindo potenciais de interação, conseguiu-se descrever a reação para as duas etapas eletroquímicas. Finalmente, como esperado, uma correlação entre o raio iônico dos dopantes e o coeficiente de difusão aparente foi estabelecida em filmes de polipirrol. Abstract in english The kinetics and thermodynamic aspects of charge transfer in conducting polymers were investigated. A restricted diffusion model was used to analyze kinetic data obtained from pulse-chronopotentiometric experiments. In poly 3-methylthiophene, the apparent diffusion coefficient decreased with the fil [...] m thickness, whereas it remained constant with the electrolyte concentration. In thin films, thermodynamic changes were characterized by cyclic voltammetry, specifically, the deconvolution of the two electronic transfers involved in the process. Using a Nernstian model including interaction potentials, the two electrochemical steps were well described. Finally, as expected, a correlation between the ionic radius of the dopants and the apparent diffusion coefficient was established in polypyrrole films.

  17. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Md. Mahbubur Rahman

    2015-02-01

    Full Text Available Conducting polymers (CPs are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective.

  18. Using artificial intelligence methods to design new conducting polymers

    Directory of Open Access Journals (Sweden)

    Ronaldo Giro

    2003-12-01

    Full Text Available In the last years the possibility of creating new conducting polymers exploring the concept of copolymerization (different structural monomeric units has attracted much attention from experimental and theoretical points of view. Due to the rich carbon reactivity an almost infinite number of new structures is possible and the procedure of trial and error has been the rule. In this work we have used a methodology able of generating new structures with pre-specified properties. It combines the use of negative factor counting (NFC technique with artificial intelligence methods (genetic algorithms - GAs. We present the results for a case study for poly(phenylenesulfide phenyleneamine (PPSA, a copolymer formed by combination of homopolymers: polyaniline (PANI and polyphenylenesulfide (PPS. The methodology was successfully applied to the problem of obtaining binary up to quinternary disordered polymeric alloys with a pre-specific gap value or exhibiting metallic properties. It is completely general and can be in principle adapted to the design of new classes of materials with pre-specified properties.

  19. Incorporation of Metallic Nanoparticles into Conducting Polymer Actuator Films

    Science.gov (United States)

    Costa, Alexsandro Santos; Li, Kwong-Chi; Kilmartin, Paul A.; Travas-Sejdic, Jadranka

    2009-07-01

    Nanocomposites of conducting polymer films (CP) with metal nanoparticles have been prepared. Electropolymerization of pyrrole on stainless steel electrodes was undertaken galvanostatically until the thickness of the polypyrrole (PPy) film reached around 7.5 ?m, which is suitable for the future application of these films in micropumps and microvalves. Subsequently platinum nanoparticles were deposited from a solution of a platinum precursor (K2PtCl6) onto the PPy coated stainless steel electrodes by applying a potential of -0.1 V for between 3 and 15 s. The length of the deposition time led to significant differences in the morphology and size of the particles obtained. The actuation of the free standing films was studied by electrochemomechanical deformation measurements (ECMD) on strips of films cycled in NaPF6. Depending upon the test conditions, the strain rate and ultimate strain of films containing Pt nanoparticles could be increased by a factor of 2 or more compared to those of pristine PPy films.

  20. A conducting polymer/ferritin anode for biofuel cell applications

    International Nuclear Information System (INIS)

    An enzyme anode for use in biofuel cells (BFCs) was constructed using an electrically connected bilayer based on a glassy carbon (GC) electrode immobilized with the conducting polymer polypyrrole (Ppy) as electron transfer enhancer, and with horse spleen ferritin protein (Frt) as electron transfer mediator. The surface-coupled redox system of nicotinamide adenine dinucleotide (NADH) catalyzed with diaphorase (Di) was used for the regeneration of NAD+ in the inner layer and the NAD+-dependent enzyme catalyst glucose dehydrogenase (GDH) in the outer layer. The outer layer of the GC-Ppy-Frt-Di-NADH-GDH electrode effectively catalyzes the oxidation of glucose biofuel continuously; using the NAD+ generated at the inner layer of the Di-catalyzed NADH redox system mediated by Frt and Ppy provides electrical communication with enhancement in electron transport. The electrochemical characteristics of the electrodes were investigated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). This anode provides a current density of 1.2 mA cm-2 in a 45 mM glucose solution and offers a good possibility for application in biofuel cells.

  1. A general approach toward enhancement of pseudocapacitive performance of conducting polymers by redox-active electrolytes

    KAUST Repository

    Chen, Wei

    2014-12-01

    A general approach is demonstrated where the pseudocapacitive performance of different conducting polymers is enhanced in redox-active electrolytes. The concept is demonstrated using several electroactive conducting polymers, including polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). As compared to conventional electrolytes, the redox-active electrolytes, prepared by simply adding a redox mediator to the conventional electrolyte, can significantly improve the energy storage capacity of pseudocapacitors with different conducting polymers. The results show that the specific capacitance of conducting polymer based pseudocapacitors can be increased by a factor of two by utilization of the redox-active electrolytes. In fact, this approach gives some of the highest reported specific capacitance values for electroactive conducting polymers. Moreover, our findings present a general and effective approach for the enhancement of energy storage performance of pseudocapacitors using a variety of polymeric electrode materials. © 2014 Elsevier B.V. All rights reserved.

  2. A review of properties and potential aerospace applications of electrically conducting polymers

    Science.gov (United States)

    Meador, Mary Ann B.; Gaier, James R.; Good, Brian S.; Sharp, G. Richard; Meador, Michael A.

    1990-01-01

    An overview of current research in conducting polymers is presented. Emphasis is placed on development of materials useful for aeronautic and space applications. Research on organic conducting polymers began in the early 1970s with the discovery of polyacetylene. Since then, many polymers which share structural characteristics with polyacetylene have been prepared which conduct electricity, especially when they are doped with suitable agents. Problems with environmental instability, difficult processing, poor mechanical properties and high cost have slowed the development of conducting polymers. However, practical use of these materials is imminent, based on recent refinements in understanding how polymers conduct, more systematic approaches to the development of new materials, and significant improvements in both the processing and properties.

  3. New Secondary Batteries Using Electronically Conductive Polymer Cathodes

    Science.gov (United States)

    Martin, Charles R.; White, Ralph E.

    1991-01-01

    A Li/Polypyrrole secondary battery was designed and built, and the effect of controlling the morphology of the polymer on enhancement of counterion diffusion in the polymer phase was explored. The experimental work was done at Colorado State University, while the mathematical modeling of the battery was done at Texas A and M University. Manuscripts and publications resulting from the project are listed.

  4. Protocol and cell responses in three-dimensional conductive collagen gel scaffolds with conductive polymer nanofibres for tissue regeneration

    OpenAIRE

    Sirivisoot, Sirinrath; Pareta, Rajesh; Harrison, Benjamin S.

    2014-01-01

    It has been established that nerves and skeletal muscles respond and communicate via electrical signals. In regenerative medicine, there is current emphasis on using conductive nanomaterials to enhance electrical conduction through tissue-engineered scaffolds to increase cell differentiation and tissue regeneration. We investigated the role of chemically synthesized polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer nanofibres for conductive gels. To mimic a na...

  5. Assembly of antimony doped tin oxide nanocrystals into conducting macroscopic aerogel monoliths.

    Science.gov (United States)

    Rechberger, Felix; Ilari, Gabriele; Niederberger, Markus

    2014-11-01

    We present the assembly of preformed antimony doped tin oxide nanobuilding blocks into centimeter sized aerogels with surface areas exceeding 340 m(2) g(-1). After calcination, the resistivity of the aerogels was decreased by 4 orders of magnitude to a few k? cm, with the primary conducting structures measuring only a few nanometers. PMID:25229075

  6. Performance of conducting polymer electrodes for stimulating neuroprosthetics

    Science.gov (United States)

    Green, R. A.; Matteucci, P. B.; Hassarati, R. T.; Giraud, B.; Dodds, C. W. D.; Chen, S.; Byrnes-Preston, P. J.; Suaning, G. J.; Poole-Warren, L. A.; Lovell, N. H.

    2013-02-01

    Objective. Recent interest in the use of conducting polymers (CPs) for neural stimulation electrodes has been growing; however, concerns remain regarding the stability of coatings under stimulation conditions. These studies examine the factors of the CP and implant environment that affect coating stability. The CP poly(ethylene dioxythiophene) (PEDOT) is examined in comparison to platinum (Pt), to demonstrate the potential performance of these coatings in neuroprosthetic applications. Approach. PEDOT is coated on Pt microelectrode arrays and assessed in vitro for charge injection limit and long-term stability under stimulation in biologically relevant electrolytes. Physical and electrical stability of coatings following ethylene oxide (ETO) sterilization is established and efficacy of PEDOT as a visual prosthesis bioelectrode is assessed in the feline model. Main results. It was demonstrated that PEDOT reduced the potential excursion at a Pt electrode interface by 72% in biologically relevant solutions. The charge injection limit of PEDOT for material stability was found to be on average 30× larger than Pt when tested in physiological saline and 20× larger than Pt when tested in protein supplemented media. Additionally stability of the coating was confirmed electrically and morphologically following ETO processing. It was demonstrated that PEDOT-coated electrodes had lower potential excursions in vivo and electrically evoked potentials (EEPs) could be detected within the visual cortex. Significance. These studies demonstrate that PEDOT can be produced as a stable electrode coating which can be sterilized and perform effectively and safely in neuroprosthetic applications. Furthermore these findings address the necessity for characterizing in vitro properties of electrodes in biologically relevant milieu which mimic the in vivo environment more closely.

  7. Methods of enhancing conductivity of a polymer-ceramic composite electrolyte

    Science.gov (United States)

    Kumar, Binod (Inventor)

    2003-01-01

    Methods for enhancing conductivity of polymer-ceramic composite electrolytes are provided which include forming a polymer-ceramic composite electrolyte film by a melt casting technique and uniaxially stretching the film from about 5 to 15% in length. The polymer-ceramic composite electrolyte is also preferably annealed after stretching such that it has a room temperature conductivity of from 10.sup.-4 S cm.sup.-1 to 10.sup.-3 S cm.sup.-1. The polymer-ceramic composite electrolyte formed by the methods of the present invention may be used in lithium rechargeable batteries.

  8. Effect of complexing salt on conductivity of PVC/PEO polymer blend electrolytes

    Indian Academy of Sciences (India)

    S Rajendran; Ravi Shanker Babu; M Usha Rani

    2011-12-01

    Solid polymer electrolyte membrane comprising poly(vinyl chloride) (PVC), poly(ehylene oxide) (PEO) and different lithium salts (LiClO4, LiBF4 and LiCF3SO3) were prepared by the solution casting technique. The effect of complexing salt on the ionic conductivity of the PVC/PEO host polymer is discussed. Solid polymer electrolyte films were characterized by X-ray diffraction, FTIR spectroscopy, TG/DTA and ac impedance spectroscopic studies. The conductivity studies of these solid polymer electrolyte (SPE) films are carried out as a function of frequency at various temperatures ranging from 302 K to 353 K. The maximum room temperature ionic conductivity is found to be 0.079 × 10-4 S cm-1 for the film containing LiBF4 as the complexing salt. The temperature dependence of the conductivity of polymer electrolyte films seems to obey the Vogel–Tamman–Fulcher (VTF) relation.

  9. Effects of ?-rays on electrical conductivity of polyvinyl alcohol-polypyrrole composite polymer films

    International Nuclear Information System (INIS)

    The composite polymer films of polyvinyl alcohol/polypyrrole/chloral hydrate (PVA-PPy-CH) had been prepared. Effects of ?-rays on the electrical conductivity of the composite polymer films had been investigated by using Inductance Resistance meter (LCR) meter at a frequency ranging from 20 Hz to 1 MHz. With the incorporation of choloral hydrate in the polymer sample, the conductivity increased indicates that it is capable to be used as dopant for polymerizing conjugated polymer. The electrical conductivity obtained increased as the dose increased, which is in the order of 10-5 Scm-1 indicates that ?-ray is capable to enhance the electrical conductivity of the composite polymer films. The parameter of s is in the range of 0.31 ? S ? 0.49 and obeyed simple power law dispersion ?S. The Scanning Electron Microscopy (SEM) micrographs reveal the formation of polypyrrole globules in polyvinyl alcohol matrix which increased as the irradiation dose was increased. (Author)

  10. Conducting polymer nanostructures for photocatalysis under visible light.

    Science.gov (United States)

    Ghosh, Srabanti; Kouamé, Natalie A; Ramos, Laurence; Remita, Samy; Dazzi, Alexandre; Deniset-Besseau, Ariane; Beaunier, Patricia; Goubard, Fabrice; Aubert, Pierre-Henri; Remita, Hynd

    2015-05-01

    Visible-light-responsive photocatalysts can directly harvest energy from solar light, offering a desirable way to solve energy and environment issues. Here, we show that one-dimensional poly(diphenylbutadiyne) nanostructures synthesized by photopolymerization using a soft templating approach have high photocatalytic activity under visible light without the assistance of sacrificial reagents or precious metal co-catalysts. These polymer nanostructures are very stable even after repeated cycling. Transmission electron microscopy and nanoscale infrared characterizations reveal that the morphology and structure of the polymer nanostructures remain unchanged after many photocatalytic cycles. These stable and cheap polymer nanofibres are easy to process and can be reused without appreciable loss of activity. Our findings may help the development of semiconducting-based polymers for applications in self-cleaning surfaces, hydrogen generation and photovoltaics. PMID:25774954

  11. Electrochemical Switching of Conductance with Diarylethene-Based Redox-Active Polymers

    DEFF Research Database (Denmark)

    Logtenberg, Hella; van der Velde, Jasper H. M.; de Mendoza, Paula; Areephong, Jetsuda; Hjelm, Johan; Feringa, Ben L.; Browne, Wesley R.

    2012-01-01

    Reversible switching of conductance using redox triggered switching of a polymer-modified electrode is demonstrated. A bifunctional monomer comprising a central electroswitchable core and two bithiophene units enables formation of a film through anodic electropolymerization. The conductivity of the polymer can be switched electrochemically in a reversible manner by redox triggered opening and closing of the diarylethene unit. In the closed state, the conductivity of the modified electrode is hig...

  12. Micropatterning of a stretchable conductive polymer using inkjet printing and agarose stamping

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Hassager, Ole; Larsen, Niels Bent; Clark, N.B.

    2007-01-01

    A highly conducting stretchable polymer material has been patterned using additive inkjet printing and by subtractive agarose stamping of a deactivation agent (hypochlorite). The material consisted of elastomeric polyurethane combined in an interpenetrating network with a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT). The agarose stamping produced 50 ?m wide conducting lines with high spatial fidelity. The deactivation agent was found to cause some degradation of the remaining con...

  13. Highly Electrically Conductive Nanocomposites Based on PolymerInfused Graphene Sponges

    OpenAIRE

    Yuanqing Li; Yarjan Abdul Samad; Kyriaki Polychronopoulou; Alhassan, Saeed M.; Kin Liao

    2014-01-01

    Conductive polymer composites require a threedimensional 3D network to impart electrical conductivity. A general method that is applicable to most polymers for achieving a desirable graphene 3D network is still a challenge. We have developed a facile technique to fabricate highly electrical conductive composite using vacuumassisted infusion of epoxy into graphene sponge GS scaffold. Macroscopic GSs were synthesized from graphene oxide solution by a hydrothermal method combined ...

  14. Preparation of metallic cation conducting polymers based on sterically hindered phenols containing polymeric systems

    Science.gov (United States)

    Skotheim, Terje A. (Shoreham, NY); Okamoto, Yoshiyuki (Fort Lee, NJ); Lee, Hung S. (Woodside, NY)

    1989-01-01

    The present invention relates to ion-conducting solvent-free polymeric systems characterized as being cationic single ion conductors. The solvent-free polymer electrolytes comprise a flexible polymer backbone to which is attached a metal salt, such as a lithium, sodium or potassium salt, of a sterically hindered phenol. The solid polymer electrolyte may be prepared either by (1) attaching the hindered phenol directly to a flexible polymeric backbone, followed by neutralization of the phenolic OH's or (2) reacting the hindered phenol with a polymer precursor which is then polymerized to form a flexible polymer having phenolic OH's which are subsequently neutralized. Preferably the hindered phenol-modified polymeric backbone contains a polyether segment. The ionic conductivity of these solvent-free polymer electrolytes has been measured to be in the range of 10.sup.-4 to 10.sup.-7 S cm.sup.-1 at room temperature.

  15. Fabrication and characterization of dry conducting polymer actuator by vapor phase polymerization of polypyrrole.

    Science.gov (United States)

    Ramasamy, Madeshwaran Sekkarapatti; Mahapatra, Sibdas Singha; Cho, Jae Whan

    2014-10-01

    A trilayered dry conducting polymer actuator was fabricated via application of a polypyrrole (PPy) coating on both sides of a solid polymer electrolyte film using vapor phase polymerization (VPP). The solid polymer electrolyte film was prepared by incorporation of different weight ratios of dodecylbenzene sulfonic acid sodium salt in poly(vinyl alcohol) (PVA) by solvent casting. The successful polymerization of PPy was confirmed by Fourier transform infrared spectroscopy; a uniform PPy coating on the solid polymer electrolyte film surface was also observed by scanning electron microscopy. The dry PVA/PPy actuator demonstrated good actuation behavior at a low applied voltage of 1-3 V. The actuator bending displacement was found to increase with an increase in the applied voltage. The VPP approach in this study provides a very effective method for achieving a uniform polymer coating in the fabrication of a dry conducting polymer actuator. PMID:25942824

  16. Molecular motion in polymer electrolytes. An investigation of methods for improving the conductivity of solid polymer electrolytes

    CERN Document Server

    Webster, M I

    2002-01-01

    Three methods were explored with a view to enhancing the ionic conductivity of polymer electrolytes; namely the addition of an inert, inorganic filler, the addition of a plasticizer and the incorporation of the electrolyte in the pores of silica matrices. There have been a number of reports, which suggest the addition of nanocrystalline oxides to polymer electrolytes increases the ionic conductivities by about a factor of two. In this thesis studies of the polymer electrolyte NaSCN.P(EO) sub 8 with added nanocrystalline alumina powder are reported which show no evidence of enhanced conductivity. The addition of a plasticizer to polymer electrolytes will increase the ionic conductivity. A detailed study was made of the polymer electrolytes LiT.P(EO) sub 1 sub 0 and LiClO sub 4.P(EO) sub 1 sub 0 with added ethylene carbonate plasticizer. The conductivities showed an enhancement, however this disappeared on heating under vacuum. The present work suggests that the plasticised system is not thermodynamically stabl...

  17. Effects of electric field and charge distribution on nanoelectronic processes involving conducting polymers

    OpenAIRE

    Ramos, Marta M. D.; Correia, Helena M. G.

    2006-01-01

    The injection of charge carriers in conducting polymer layers gives rise to local electric fields which should have serious implications on the charge transport through the polymer layer. The charge distribution and the related electric field inside the ensemble of polymer molecules, with different molecular arrangements at nanoscale, determine whether or not intra-molecular charge transport takes place and the preferential direction for charge hopping between neighbouring molecules. Conseque...

  18. Síntese de polímeros condutores em matrizes sólidas hospedeiras Conductive polymer synthesis in solid host matrices

    OpenAIRE

    Daltamir J. Maia; Marco-A. De Paoli; Alves, Oswaldo L; Aldo J. G. Zarbin; Silmara das Neves

    2000-01-01

    This review discusses the methods used to prepare conductive polymers in confined environments. This spatial restriction causes formation of defect-free polymer chains in the interlayer as porous cavities of inorganic hosts. The properties of the different composites obtained are a synergist combination of the characteristics of the inorganic host and the polymer. This opens new perspectives for the preparation of these materials and widens its potential applications.

  19. Síntese de polímeros condutores em matrizes sólidas hospedeiras / Conductive polymer synthesis in solid host matrices

    Scientific Electronic Library Online (English)

    Daltamir J., Maia; Marco-A., De Paoli; Oswaldo L., Alves; Aldo J. G., Zarbin; Silmara das, Neves.

    2000-04-01

    Full Text Available [...] Abstract in english This review discusses the methods used to prepare conductive polymers in confined environments. This spatial restriction causes formation of defect-free polymer chains in the interlayer as porous cavities of inorganic hosts. The properties of the different composites obtained are a synergist combina [...] tion of the characteristics of the inorganic host and the polymer. This opens new perspectives for the preparation of these materials and widens its potential applications.

  20. Conducting polymers as driving electrodes for Polymer-Dispersed Liquid-Crystals display devices: On the electro-optical efficiency

    Science.gov (United States)

    Roussel, F.; Chan-Yu-King, R.; Buisine, J.-M.

    2003-07-01

    Intrinsically conducting polymer (ICP) thin films are used as driving electrodes for Polymer-Dispersed Liquid-Crystals (PDLC) display devices. In order to investigate the electro-optical efficiency of these organic electrodes, three different kinds of conducting polymers, i.e. polyaniline doped with 10-camphorsulfonic acid (PANI(HCSA)), polypyrrole doped with dodecylbenzenesulfonic acid (PPY(DBSA)), and polyethylenedioxythiophene doped with polystyrenesulfonate (PEDOT(PSS)), were prepared or purchased, and coated either on glass or plastic substrates. Optical absorption studies in the UV-Vis range of the conducting polymer-coated substrates were first performed showing the presence of conducting species for the three types of polymers. The electrical characteristics of the resulting films were measured with the four-probes technique. PANI(HCSA) exhibits a higher conductivity ?sim 122\\un{S\\cdot cm^{-1}} (R_S=1.2 ; 10^3; ?\\cdotBox^{ -1}) compared to PPY(DBSA) ?sim 2.6\\un{S\\cdot cm^{-1}} (R_S=150.7 ;10^3;?\\cdotBox^{-1}), and PEDOT(PSS) ?sim 1.6\\un{S\\cdot cm^{-1}} (R_S=637.3 ; 10^3; ?\\cdotBox^{-1}). It is also shown that for a given conducting polymer, its electrical conductivity decreases when a plastic substrate is used. These observations have been related to significant morphological changes observed by scanning electron microscopy (SEM). A mixture of Norland Optical Adhesive 65 and nematic liquid-crystal E7 in the weight ratio (\\chem{35:65}) was used as precursor of the PDLC material. Better electro-optical responses (transmission properties, drive voltages and switching times) of PDLC films were obtained for devices prepared with (PPY(DBSA))-based electrodes. The electro-optical performances of the PDLC display devices also depend on the nature of the ICP substrate used.

  1. Effect of plasticizer and fumed silica on ionic conductivity behaviour of proton conducting polymer electrolytes containing HPF6

    Indian Academy of Sciences (India)

    Jitender Paul Sharma; S S Sekhon

    2013-08-01

    The effect of addition of propylene carbonate (PC) and nano-sized fumed silica on the ionic conductivity behaviour of proton conducting polymer electrolytes containing different concentrations of hexafluorophosphoric acid (HPF6) in polyethylene oxide (PEO) has been studied. The addition of PC results in an increase in ionic conductivity, whereas the addition of nano-sized fumed silica improves mechanical strength of electrolytes along with a small increase in ionic conductivity. It was observed that the simultaneous addition of PC and fumed silica results in electrolytes with optimum value of ionic conductivity and other properties.

  2. Regiochemistry of Poly(3-Hexylthiophene): Synthesis and Investigation of a Conducting Polymer

    Science.gov (United States)

    Pappenfus, Ted M.; Hermanson, David L.; Kohl, Stuart G.; Melby, Jacob H.; Thoma, Laura M.; Carpenter, Nancy E.; Filho, Demetrio A. da Silva; Bredas, Jean-Luc

    2010-01-01

    A series of experiments for undergraduate laboratory courses (e.g., organic, polymer, inorganic) have been developed. These experiments focus on understanding the regiochemistry of the conducting polymer poly(3-hexylthiophene) (P3HT). The substitution patterns in P3HTs control their conformational features, which, in turn, dictates the [pi]…

  3. An Integrated Laboratory Approach toward the Preparation of Conductive Poly(phenylene vinylene) Polymers

    Science.gov (United States)

    Knoerzer, Timm A.; Balaich, Gary J.; Miller, Hannah A.; Iacono, Scott T.

    2014-01-01

    Poly(phenylene vinylene) (PPV) represents an important class of conjugated, conducting polymers that have been readily exploited in the preparation of organic electronic materials. In this experiment, students prepare a PPV polymer via a facile multistep synthetic sequence with robust spectroscopic evaluation of synthetic intermediates and the…

  4. Flow instability and electrical conductivity of composites of hard metal carbides in polymer matrix.

    Czech Academy of Sciences Publication Activity Database

    Vil?áková, J.; Hausnerová, B.; Sáha, P.; Quadrat, Otakar

    Montreal : Canadian Society of Rheology, 2001, s. 1-7. [Polymer Processing Society Annual Meeting /17./. Montreal (CA), 21.05.2001-24.05.2001] R&D Projects: GA AV ?R KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : flow instability * electrical conductivity * metal carbides-polymer composites Subject RIV: CD - Macromolecular Chemistry

  5. Conductivity studies of a chitosan-based polymer electrolyte

    International Nuclear Information System (INIS)

    Ionic conductivity for the chitosan-NH4CF3SO3 system was conducted over a wide range of frequency and at temperatures between 298 and 313 K. Dielectric data were analyzed using complex permittivity ? * and complex electrical modulus M * for the sample with the highest ionic conductivity at various temperatures. The temperature-dependent conductivity data obeys Arrhenius relationship. Jonschers universal power law was used to analyze AC conductivity of the sample. Hopping frequency was determined and activation energy of hopping is almost equal to the activation energy of conduction. The AC conductivity master curve was obtained for the highest conducting sample when scaled vertically by ? DC and horizontally by ? P

  6. Novel alkaline polymer electrolyte for water electrolysis with enhanced conductivity.

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Bouzek, B.; Paidar, M.; Schauer, Jan

    Praha : Process Engineering, 2010. s. 110-111. ISBN 978-80-02-02246-6. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ and European Congress of Chemical Engineering ECCE-7 /7./. 28.08.2010-01.09.2010, Praha] Institutional research plan: CEZ:AV0Z40500505 Keywords : novel alkaline polymer * polyelectrolytes Subject RIV: CD - Macromolecular Chemistry

  7. Carbon nanotubes coated with a conducting polymer, polyaniline.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Konyushenko, Elena; Trchová, Miroslava; Sapurina, I.; Kazantseva, N. E.; Tomishko, M. M.; Demicheva, O. M.

    Rio de Janeiro : International Union of Pure and Applied Chemistry, 2006, s. 1-2. [World Polymer Congress Macro 2006 /41./. Rio de Janeiro (BR), 16.07.2006-21.07.2006] R&D Projects: GA AV ?R IAA4050313 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbon nanotubes * ferromagnetism * polyaniline Subject RIV: CD - Macromolecular Chemistry

  8. FINAL REPORT. SENSORS USING MOLECULAR RECOGNITION IN LUMINESCENT, CONDUCTIVE POLYMERS

    Science.gov (United States)

    The purpose of this project is to develop sensor technology for detecting specific heavy metal ions, such as transition metals, lead, lanthanides, and actinides in waste streams. The sensing strategy uses molecular recognition of the metal ions by polymers that change their lumin...

  9. Anticorrosion efficiency of zinc-filled epoxy coatings containing conducting polymers and pigments.

    Czech Academy of Sciences Publication Activity Database

    Kalendová, A.; Veselý, D.; Kohl, M.; Stejskal, Jaroslav

    2015-01-01

    Ro?. 78, January (2015), s. 1-20. ISSN 0300-9440 Institutional support: RVO:61389013 Keywords : conducting polymer * zinc metal * organic coating Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.358, year: 2014

  10. ION AND MOLECULE SENSORS USING MOLECULAR RECOGNITION IN LUMINESCENT, CONDUCTIVE POLYMERS

    Science.gov (United States)

    This program integrates three individual, highly interactive projects that will use molecular recognition strategies to develop sensor technology based on luminescent, conductive polymers that contain sites for binding specific molecules or ions in the presence of related molecul...

  11. BIOAFFINITY SENSORS BASED ON CONDUCTING POLYMERS: A SHORT REVIEW. (R825323)

    Science.gov (United States)

    The development of new electrode materials has expanded the range and classes of detectable compounds using electroanalytical methods. Conducting electroactive polymers (CEPs) have been demonstrated to have remarkable sensing applications through their ability to be reversibly ox...

  12. Design of conducting polymer matrix derived from the C{sub 60}-based star-shaped polymer

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, L.Y.; Wang, L.Y. [National Taiwan Univ., Taipei (Taiwan, Province of China)

    1995-12-01

    Synthetic methods leading to the preparation of water-soluble polyhydroxylated C{sub 60} derivative (fullerenol) have been extensively investigated recently. This type of molecule, containing multiple polar hydroxyl functions in a ball-shaped fullerene structure, is suitable for utilization as a versatile intermediate in the prospective design of three-dimensionally stretched polymers. The strategy involves the use of fullerenol as a molecular core for anchoring various polymer arms on the C{sub 60} cage. Since the spherical space of fullerenol, covering the outer radius of hydroxyl groups, is in a diameter of approximately 13 {Angstrom}. The truly star-bursted polymer molecules can be made. The treatment of fullerenol with a prepolymer of diisocyanated urethane polyether under a mild condition afforded the C{sub 60}-based polyurethane polyether star-polymers with a narrow distribution of the number of polymer arms. We will discuss the use of C{sub 60}-based star-shaped polymer in the design and fabrication of polyaniline analog conducting polymer matrix.

  13. Investigation of electrode patterns suitable for nano-litre drop coated conducting polymer composite sensors

    OpenAIRE

    Arshak, Khalil; Cunniffe, Colm; Moore, Edward G.; Cavanagh, Leon M.

    2006-01-01

    This study presents an analysis of electrode patterns suitable for use with drop coated conducting polymer gas sensors. A thin-film technique was used to efficiently fabricate the copper electrode patterns [1]. Conducting Polymer Composite (CPC) materials were deposited using a 500 nano-litre syringe onto the electrode patterns to produce an array of sensors for organic solvent vapour detection. The sensors were exposed to propanol vapour in steps of 3000 ppm from a minimum concentratio...

  14. DOPANT FLEXIBILITY AND PROCESSABILITY STUDIES WITH ELECTRICALLY CONDUCTIVE, FACE-TO-FACE METALLOMACROCYCLIC POLYMERS

    OpenAIRE

    Inabe, T.; Lyding, J; Moguel, M.; Marks, T.

    1983-01-01

    In doping experiments on the cofacially arrayed phthalocyanine polymer [Si(Pc)O]n using high potential quinone, halogen, or nitrosyl electron acceptors, the achievable degree of partial oxidation, the inhomogeneity of the doping process, and the conductivity mechanism remain remarkably constant. Using wet spinning techniques, it has proven possible to prepare electrically conductive fibers of [Si(Pc)O]n alone or blended with the high performance aramid polymer Kevlar.

  15. Properties and processing by extrusion of electrically conductive multilayer filaments comprising polymer composites

    OpenAIRE

    R S Martins; Gonçalves, Renato Ferreira; Azevedo, Tiago; Nóbrega, J.M.; Carvalho, Helder; Lanceros-Méndez, S.; Rocha, J.G.

    2013-01-01

    This work describes the production and characterization of three-layer piezoelectric filaments using two different electrically conductive polymers. The filaments were produced in a filament extrusion line, equipped with a coextrusion die that enabled a coaxial arrangement for a three-layer filament. For the inner and outer layers two different electrically conductive compounds were used, and the middle layer was made of the electroactive polymer PVDF. The produced filament can be used as a p...

  16. Electrochemical evaluation of the p-Si/conducting polymer interfacial properties

    Science.gov (United States)

    Nagasubramanian, G.; Distefano, S.; Moacanin, J.

    1988-01-01

    Results are presented from an experimental investigation of the contact resistance and interfacial properties of a p-Si/conducting polymer interface for solar cell applications. The electronic character of the polymer/semiconductor function is determined by studying the electrochemical behavior of both poly(isothianapthene) (PITN) and polypyrrole (PP) in an acetonitrile solution on p-silicon electrodes. The results obtained indicate that while PITN is intrinsically more conductive than PP, neither passivates surface states nor forms ohmic contact.

  17. OPTIMIZED DESIGN OF BIO-SENSOR USING CONDUCTING POLYMERS AND NANOCOMPOSITES

    OpenAIRE

    Usha.A,; Ramachandra, B

    2011-01-01

    This Research work is focused on the design, development and technological evolution of emerging fields of Nanotechnology and Conducting Polymer Electronics, Bio-Tech based Embedded Sensors and Smart Systems employing System-0n- Chip (SOC) Core, as applied to Health Monitoring of Human and Complex Systems in Engineering and Medicine. With the Invention of Thin-Film Technology, it is now possible to fabricate Novel Conducting-Polymer based sensors and devices with built-in-flexible electronics...

  18. A unified model for temperature dependent electrical conduction in polymer electrolytes

    OpenAIRE

    Mikrajuddin; Lenggoro, I. Wuled; Okuyama, Kikuo

    2001-01-01

    The observed temperature dependence of electrical conduction in polymer electrolytes is usually fitted with two separated equations: an Arrhenius equation at low temperatures and Vogel-Tamman-Fulcher (VTF) at high temperatures. We report here a derivation of a single equation to explain the variation of electrical conduction in polymer electrolytes at all temperature ranges. Our single equation is in agreement with the experimental data

  19. Design, synthesis, characterization and development of novel organic conducting polymers with technological applications

    OpenAIRE

    Aradilla Zapata, David

    2013-01-01

    In this thesis, a series of novel organic conducting polymers have been synthesized using alternative methods based on electrochemical techniques, which have allowed to broaden the knowledge in the field of the characterization by means of topological, spectroscopic, electrochemical and structural techniques. Among the variety of synthesis techniques of conducting polymers, layer-by-layer (LbL) has been one of the most important to build multilayered systems. Thus, in this thesis ...

  20. Hot-pressed Ag+ Ion Conducting Glass-Polymer Electrolytes: Synthesis and Battery Application

    Scientific Electronic Library Online (English)

    Angesh, Chandra.

    2012-07-01

    Full Text Available Synthesis of new Ag+ ion conducting glass-polymer electrolytes (GPEs): (1-x) PEO: x [0.75(0.75AgI:0.25AgCl):0.25(Ag2O:P2O5)], where 0 [...] )], with conductivity (?) ? 6.0 × 10-6 S cm-1, was identified from the compositional dependent conductivity studies and this has been referred to as the Optimum Conducting Composition (OCC). Approximately three orders of conductivity enhancement have been achieved in GPE OCC from that of the pure polymer PEO. The glass-polymer complexation has been confirmed by SEM and DSC analysis. Ion transport parameters viz. ionic conductivity (?), ionic mobility (?), mobile ion concentration (n) and ionic transference number (tion) have been characterized using different experimental techniques. Solid-state polymeric batteries were fabricated using GPE OCC as electrolyte and the cell-potential discharge characteristics were studied under different load conditions at room temperature.

  1. Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

    International Nuclear Information System (INIS)

    We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10-4 to 10-3 S cm-1 at room temperature. Gelation was found to cause little change in the 7Li diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids

  2. BF3-doped polyaniline: A novel conducting polymer

    Indian Academy of Sciences (India)

    Debangshu Chaudhuri; D D Sarma

    2006-07-01

    We review the unusual structural, transport and magnetic properties of highly conducting polyaniline, doped with boron trifluoride. Our studies establish the unique conducting state of this system, which is in distinct contrast with the conventional proton-doped polyaniline samples.

  3. Stability of electrical properties of conducting polymer composites.

    Czech Academy of Sciences Publication Activity Database

    Omastová, M.; Prokeš, J.; Košina, S.; Hlavatá, Drahomíra

    2001-01-01

    Ro?. 170, - (2001), s. 241-248. ISSN 1022-1360. [Property Tailoring of Thermoplastics-Based Blends and Composites.. Bratislava, 01.10.2000-04.10.2000] R&D Projects: GA ?R GA106/99/0556; GA AV ?R KSK2050602 Institutional research plan: CEZ:AV0Z4050913 Keywords : electrical properties * polymer composites * carbon black Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.634, year: 2001

  4. Conducting Polymer Actuators for Medical Devices and Cell Mechanotransduction

    OpenAIRE

    Jager, Edwin

    2013-01-01

    Actuators made of conjugated polymers such aspolypyrrole are interesting candidates as active elements inmedical devices since they can be fabricated in small sizes andoperated in saline solutions. In addition they can bemicrofabricated and integrated on silicon chips for instance forlab-on-a-chip and cell biology applications. Here, devicescomprising polypyrrole (PPy) microactuators for mechanicalstimulation of single cells are presented. In addition, novelinterfacing and patterning methods ...

  5. Proton conductive polymer gel electrolytes based on methacrylates.

    Czech Academy of Sciences Publication Activity Database

    Reiter, Jakub; Velická, Jana; Míka, M.

    Brno : University of Technology Brno, 2007, s. 72-75. ISBN 978-80-214-3424-0. [International Conference Advanced Batteries and Accumulators /8./. Brno (CZ), 03.06.2007-07.06.2007] R&D Projects: GA MŠk LC523; GA ?R GA106/04/1279; GA ?R(CZ) GA104/06/1471 Institutional research plan: CEZ:AV0Z40320502 Keywords : polymer gel electrolytes * solid and polymeric conductors Subject RIV: CG - Electrochemistry

  6. Thermal stability of the conducting polymer-ionic liquid composite.

    Czech Academy of Sciences Publication Activity Database

    Trchová, Miroslava; Šed?nková, Ivana; Morávková, Zuzana; Stejskal, Jaroslav

    Prague : Institute of Macromolecular Chemistry AS CR, v. v. i, 2013. s. 71. ISBN 978-80-85009-77-4. [European Symposium on Polymer Spectroscopy /19./ - ESOPS19. Prague Meeting on Macromolecules /77./. 07.07.2013-11.07.2013, Prague] R&D Projects: GA ?R GAP205/12/0911 Institutional support: RVO:61389013 Keywords : polyaniline * ionic liquid * thermal stability Subject RIV: CD - Macromolecular Chemistry

  7. Substitutional doping in nanocrystal superlattices

    Science.gov (United States)

    Cargnello, Matteo; Johnston-Peck, Aaron C.; Diroll, Benjamin T.; Wong, Eric; Datta, Bianca; Damodhar, Divij; Doan-Nguyen, Vicky V. T.; Herzing, Andrew A.; Kagan, Cherie R.; Murray, Christopher B.

    2015-08-01

    Doping is a process in which atomic impurities are intentionally added to a host material to modify its properties. It has had a revolutionary impact in altering or introducing electronic, magnetic, luminescent, and catalytic properties for several applications, for example in semiconductors. Here we explore and demonstrate the extension of the concept of substitutional atomic doping to nanometre-scale crystal doping, in which one nanocrystal is used to replace another to form doped self-assembled superlattices. Towards this goal, we show that gold nanocrystals act as substitutional dopants in superlattices of cadmium selenide or lead selenide nanocrystals when the size of the gold nanocrystal is very close to that of the host. The gold nanocrystals occupy random positions in the superlattice and their density is readily and widely controllable, analogous to the case of atomic doping, but here through nanocrystal self-assembly. We also show that the electronic properties of the superlattices are highly tunable and strongly affected by the presence and density of the gold nanocrystal dopants. The conductivity of lead selenide films, for example, can be manipulated over at least six orders of magnitude by the addition of gold nanocrystals and is explained by a percolation model. As this process relies on the self-assembly of uniform nanocrystals, it can be generally applied to assemble a wide variety of nanocrystal-doped structures for electronic, optical, magnetic, and catalytic materials.

  8. A Route for Polymer Nanocomposites with Engineered Electrical Conductivity and Percolation Threshold

    Directory of Open Access Journals (Sweden)

    Lawrence T. Drzal

    2010-02-01

    Full Text Available Polymer nanocomposites with engineered electrical properties can be made by tuning the fabrication method, processing conditions and filler’s geometric and physical properties. This work focuses on investigating the effect of filler’s geometry (aspect ratio and shape, intrinsic electrical conductivity, alignment and dispersion within the polymer, and polymer crystallinity, on the percolation threshold and electrical conductivity of polypropylene based nanocomposites. The conductive reinforcements used are exfoliated graphite nanoplatelets, carbon black, vapor grown carbon fibers and polyacrylonitrile carbon fibers. The composites are made using melt mixing followed by injection molding. A coating method is also employed to improve the nanofiller’s dispersion within the polymer and compression molding is used to alter the nanofiller’s alignment.

  9. Li-ion conduction in PVAc based polymer blend electrolytes for lithium battery applications

    International Nuclear Information System (INIS)

    Highlights: ? PVAc/PVdF-co-HFP based polymer blend electrolyte for various concentration of LiClO4 were prepared and characterized. ? It is found that all the prepared electrolyte systems exhibited a maximum ionic conductivity of the order of x10-4 Scm-1. ? Surface morphology of the polymer electrolyte membrane sample having maximum ionic conductivity is studied by atomic force microscopy. ? SEM and DSC studies were also carried in the present study. - Abstract: The present work describes the Li-ion conduction in Poly(vinyl acetate) (PVAc) based polymer blend electrolytes have been synthesized by solvent casting technique for lithium battery applications. Characterization by XRD, SEM, AFM, FTIR, TG/DTA and photoluminescence was performed for synthesized polymer electrolytes. The thermal behaviour of the samples was ascertained from differential scanning calorimeter (DSC) and TG/DTA. The temperature dependence of conductivity of the polymer electrolytes was measured and the maximum ionic conductivity of 0.5269 x 10-4 Scm-1 at 303 K for PVAc:PVdF-co-HFP ((25/75) wt%):LiClO4 (8 wt%) complex. Surface morphology was examined from various surface scanning techniques such as scanning electron microscope (SEM) and atomic force microscope (AFM). Photoluminescence measurements demonstrated that the PVAc based polymer blend electrolyte shows minimum intensity and the results are detailed in this paper.

  10. Li-ion conduction in PVAc based polymer blend electrolytes for lithium battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Ulaganathan, M., E-mail: nathanphysics@gmail.com [School of Physics, Alagappa University, Karaikudi, Tamil Nadu 630003 (India); ZECA Power Pte Ltd, 16D Enterprise Road Enterprise 10, Singapore 627653 (Singapore); Pethaiah, S. Sundar [Gashub Technology Pte Ltd, No. 17 Wodlands Terrace, Woodlands East Industrial Estate, Singapore 738442 (Singapore); Rajendran, S., E-mail: sraj54@yahoo.com [School of Physics, Alagappa University, Karaikudi, Tamil Nadu 630003 (India)

    2011-09-15

    Highlights: {yields} PVAc/PVdF-co-HFP based polymer blend electrolyte for various concentration of LiClO{sub 4} were prepared and characterized. {yields} It is found that all the prepared electrolyte systems exhibited a maximum ionic conductivity of the order of x10{sup -4} Scm{sup -1}. {yields} Surface morphology of the polymer electrolyte membrane sample having maximum ionic conductivity is studied by atomic force microscopy. {yields} SEM and DSC studies were also carried in the present study. - Abstract: The present work describes the Li-ion conduction in Poly(vinyl acetate) (PVAc) based polymer blend electrolytes have been synthesized by solvent casting technique for lithium battery applications. Characterization by XRD, SEM, AFM, FTIR, TG/DTA and photoluminescence was performed for synthesized polymer electrolytes. The thermal behaviour of the samples was ascertained from differential scanning calorimeter (DSC) and TG/DTA. The temperature dependence of conductivity of the polymer electrolytes was measured and the maximum ionic conductivity of 0.5269 x 10{sup -4} Scm{sup -1} at 303 K for PVAc:PVdF-co-HFP ((25/75) wt%):LiClO{sub 4} (8 wt%) complex. Surface morphology was examined from various surface scanning techniques such as scanning electron microscope (SEM) and atomic force microscope (AFM). Photoluminescence measurements demonstrated that the PVAc based polymer blend electrolyte shows minimum intensity and the results are detailed in this paper.

  11. Cellulose nanocrystals: synthesis, functional properties, and applications

    Science.gov (United States)

    George, Johnsy; Sabapathi, SN

    2015-01-01

    Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. PMID:26604715

  12. Nanocrystal quantum dots

    CERN Document Server

    Klimov, Victor I

    2010-01-01

    Showing advancements in colloidal nanocrystals and quantum-confined nanostructures, this title focuses on the semiconductor nanocrystals known as nanocrystal quantum dots. This title includes chapters on carrier multiplication, doping of semiconductor nanocrystals, and applications of nanocrystals in biology.

  13. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes.

    Science.gov (United States)

    Ventura, Isaac Aguilar; Zhou, Jian; Lubineau, Gilles

    2015-12-01

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations. PMID:26676996

  14. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes

    KAUST Repository

    Ventura, Isaac Aguilar

    2015-12-16

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations.

  15. Copper Selenide Nanocrystals for Photothermal Therapy

    OpenAIRE

    Hessel, Colin M.; Pattani, Varun; Rasch, Michael; Panthani, Matthew G.; Koo, Bonil; Tunnell, James W; Korgel, Brian A

    2011-01-01

    Ligand-stabilized copper selenide (Cu2?xSe) nanocrystals, approximately 16 nm in diameter, were synthesized by a colloidal hot injection method and coated with amphiphilic polymer. The nanocrystals readily disperse in water and exhibit strong near infrared (NIR) optical absorption with a high molar extinction coefficient of 7.7 × 107 cm?1 M?1 at 980 nm. When excited with 800 nm light, the Cu2?xSe nanocrystals produce significant photothermal heating with a photothermal transduction efficiency...

  16. Electron-donor dopant, method of improving conductivity of polymers by doping therewith, and a polymer so treated

    Energy Technology Data Exchange (ETDEWEB)

    Liepins, R.; Aldissi, M.

    1988-07-05

    The electrically conductive material is described comprising a polymer with a conjugated backbone selected from the group consisting of polyacetylene, polypyrrone, and polyphenylquinoxaline, the polymer being electron-donor doped to a controlled degree with an agent derived from an electride dopant or a dopant derived from an alkalide both of which contain a trapping agent being selected from the group consisting of: a crown ether, 1,4,7,10,13,16-hexaoxacyclooctadecane, cryptand, methyl ether cyclodextrin, spherand, methyl ether calixarene, podand, and an octopus molecule, the agent being made in the presence of lithium.

  17. An all-polymer micropump based on the conductive polymer poly(3,4-ethylenedioxythiophene) and a polyurethane channel system

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; West, Keld; Hassager, Ole; Larsen, Niels Bent

    2007-01-01

    An all-polymer micropunlp was realized using the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDT) as the active cODlponent. The pUlnping effect originated fronl an ac potential applied to an aSylnlnetric array of interdigitat.ed electrodes. The PEDT electrodes were fabricated using optical lithography and reactive ion etching, and dimensions down to 2 jtD) could be successfully realize·d. The channel systeDl wasm.ade froln a flexible thennoplastic polyurethane. The chosen polyurethane ...

  18. One-step inkjet printing of conductive silver tracks on polymer substrates

    International Nuclear Information System (INIS)

    A one-step process to fabricate conductive features on flexible polymer substrates by inkjet printing an organometallic silver ink directly onto a substrate that is heated to 130 deg. C is presented. This process led to the immediate sintering of the printed features. The samples were left for 5 min at elevated temperature, which resulted in conductive silver features with a resistivity of eight times the bulk silver value. The combination of this ink and the simultaneous printing/sintering process opens up routes for the direct fabrication of conductive features on common polymer substrates that could be applied, for example, in roll-to-roll production of flexible microelectronic systems.

  19. Electronic grade and flexible semiconductor film employing oriented attachment of colloidal ligand-free PbS and PbSe nanocrystals at room temperature

    Science.gov (United States)

    Shanker, G. Shiva; Swarnkar, Abhishek; Chatterjee, Arindom; Chakraborty, S.; Phukan, Manabjyoti; Parveen, Naziya; Biswas, Kanishka; Nag, Angshuman

    2015-05-01

    Electronic grade semiconductor films have been obtained via the sintering of solution processed PbS and PbSe nanocrystals at room temperature. Prior attempts to achieve similar films required the sintering of nanocrystals at higher temperatures (>350 °C), which inhibits the processing of such films on a flexible polymer substrate, and it is also expensive. We reduced the sintering temperature by employing two important strategies: (i) use of ligand-free nanocrystals and (ii) oriented attachment of nanocrystals. Colloidal ligand-free PbS and PbSe nanocrystals were synthesized at 70 °C with high yield (~70%). However, these nanocrystals start to agglomerate with time in formamide, and upon the removal of the solvation energy, nanocrystals undergo oriented attachment, forming larger elongated crystals. PbS and PbSe nanocrystal films made on both glass and flexible substrates at room temperature exhibit Ohmic behavior with optimum DC conductivities of 0.03 S m-1 and 0.08 S m-1, respectively. Mild annealing of the films at 150 °C increases the conductivity values to 1.1 S m-1 and 137 S m-1 for PbS and PbSe nanocrystal films, respectively. AC impedance was measured to distinguish the contributions from grain and grain boundaries to the charge transport mechanism. Charge transport properties remain similar after the repeated bending of the film on a flexible polymer substrate. Reasonably high thermoelectric Seebeck coefficients of 600 ?V K-1 and 335 ?V K-1 for PbS and PbSe nanocrystal pellets, respectively, were obtained at room temperature.Electronic grade semiconductor films have been obtained via the sintering of solution processed PbS and PbSe nanocrystals at room temperature. Prior attempts to achieve similar films required the sintering of nanocrystals at higher temperatures (>350 °C), which inhibits the processing of such films on a flexible polymer substrate, and it is also expensive. We reduced the sintering temperature by employing two important strategies: (i) use of ligand-free nanocrystals and (ii) oriented attachment of nanocrystals. Colloidal ligand-free PbS and PbSe nanocrystals were synthesized at 70 °C with high yield (~70%). However, these nanocrystals start to agglomerate with time in formamide, and upon the removal of the solvation energy, nanocrystals undergo oriented attachment, forming larger elongated crystals. PbS and PbSe nanocrystal films made on both glass and flexible substrates at room temperature exhibit Ohmic behavior with optimum DC conductivities of 0.03 S m-1 and 0.08 S m-1, respectively. Mild annealing of the films at 150 °C increases the conductivity values to 1.1 S m-1 and 137 S m-1 for PbS and PbSe nanocrystal films, respectively. AC impedance was measured to distinguish the contributions from grain and grain boundaries to the charge transport mechanism. Charge transport properties remain similar after the repeated bending of the film on a flexible polymer substrate. Reasonably high thermoelectric Seebeck coefficients of 600 ?V K-1 and 335 ?V K-1 for PbS and PbSe nanocrystal pellets, respectively, were obtained at room temperature. Electronic supplementary information (ESI) available: Powder XRD, TEM, surface profilometry, infrared absorption, FESEM, I vs. V plot, ?-potential, and PL data. See DOI: 10.1039/c5nr01016k

  20. Printed organic conductive polymers thermocouples in textile and smart clothing applications.

    Science.gov (United States)

    Seeberg, Trine M; Røyset, Arne; Jahren, Susannah; Strisland, Frode

    2011-01-01

    This work reports on an experimental investigation of the potential of using selected commercially available organic conductive polymers as active ingredients in thermocouples printed on textiles. Poly(3, 4-ethylenedioxythiophene): poly(4 styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI) were screen printed onto woven cotton textile. The influence of multiple thermocycles between 235 K (-38 °C) and 350 K (+77 °C) on resistivity and thermoelectric properties was examined. The Seebeck coefficients of PEDOT:PSS and PANI were found to be about +18 ?V/K and +15 uV/K, respectively, when "metal-polymer" thermocouples were realized by combining the polymer with copper. When "polymer-polymer" thermocouples were formed by combining PEDOT:PSS and PANI, a thermoelectric voltage of about +10 ?V/K was observed. A challenge recognized in the experiments is that the generated voltage exhibited drift and fluctuations. PMID:22255039

  1. The material combining conducting polymer and ionic liquid: hydrogen bonding interactions between polyaniline and imidazolium salt.

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Dybal, Ji?í; Trchová, Miroslava

    2014-01-01

    Ro?. 197, November (2014), s. 168-174. ISSN 0379-6779 R&D Projects: GA ?R(CZ) GA13-08944S Institutional support: RVO:61389013 Keywords : conducting polymer * conductivity * imidazolium salt Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.252, year: 2014

  2. Influence of prehistory of polymer samples on radiation electric conductivity induced by ionizing radiation

    International Nuclear Information System (INIS)

    Radiation electric conductivity of PS films prepared from solutions in various solvents at various initial concentrations and temperatures and various power of absorbed dose (?-radiation of 60Co) has been measured. The results are compared with the change of density of films and existing theoretical concepts of the role of microvoids and free volume in electrical conductivity of a polymer

  3. Single lithium-ion conducting polymer electrolytes based on poly[(4-styrenesulfonyl)(trifluoromethanesulfonyl)imide] anions

    International Nuclear Information System (INIS)

    Highlights: ? Single lithium-ion conducting polymer electrolytes based on highly delocalized polyanions are prepared. ? Phase behavior and transport properties are measured. ? They show high lithium ion transference number approaching unity. ? They show high ionic conductivity at room temperature. - Abstract: New single lithium-ion conducting polymer electrolytes are prepared by a copolymerization of the two monomers, lithium (4-styrenesulfonyl)(trifluoromethanesulfonyl)imide (LiSTFSI) and methoxy-polyethylene glycol acrylate (MPEGA, CH2=CHCO2-(CH2CH2O)n-CH3, n = 8) in various monomer ratios. The structures and compositions of the prepared lithium poly[(4-styrenesulfonyl)(trifluoromethanesulfonyl) imide-co-methoxy-polyethylene glycol acrylate] (Li[PSTFSI-co-MPEGA]) copolymers are characterized by 1H and 19F NMR, and gel permeation chromatography (GPC). For comparison, the corresponding blended polymer electrolytes comprising lithium poly[(4-styrenesulfonyl) (trifluoromethanesulfonyl)imide] (LiPSTFSI) and poly(ethylene oxide) (PEO) are also prepared and characterized. The fundamental properties of these two types of lithium-ion conducting polymer electrolytes are comparatively studied, in terms of phase transitions, thermal stability, XRD, ionic conductivities, lithium-ion transference numbers (tLi+), and electrochemical stabilities. Both types of the polymer electrolytes are thermally stable up to 300 °C. While both types of polymer electrolytes exhibit single lithium-ion conducting behavior with tLi+ > 0.9, the solid-state ionic conductivities of the Li[PSTFSI-co-MPEGA] copolymer electrolytes are all higher by 1–3 orders in magnitude than those of the blended ones, irrespective of the concentration of lithium ions. The highest ionic conductivities for the copolymer electrolytes are 7.6 × 10?6 S cm?1 at 25 °C and reach 10?4 S cm?1 at 60 °C, which are obtained at the ethylene oxide (EO) unit/Li+ ratio of 20.5

  4. Electrical conductivity of polyaniline doped PVC–PMMA polymer blends

    Indian Academy of Sciences (India)

    S H Deshmukh; D K Burghate; V P Akhare; V S Deogaonkar; P T Deshmukh; M S Deshmukh

    2007-02-01

    The electrical conductivity of polyaniline doped polyvinylchloride (PVC) and poly(methyl methacrylate) (PMMA) thin films has been measured by studying the – characteristics at various temperatures in the range 323–363 K. The results are presented in the form of – characteristics and analysis has been made by interpretation of Poole–Frenkel, Fowler–Nordheim, Schottky ln() vs plots, Richardson and Arrhenius plots. The analysis of these results suggests that Schottky and Richardson mechanisms are primarily responsible for the observed conduction.

  5. Rate dependence of electrical and mechanical properties of conductive polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    Foley J.R.

    2015-01-01

    Full Text Available Conductive polymer nanocomposites with enhanced electrical and thermal properties show promise as an alternative solution for electronic materials. For example, electronic interconnect materials will have comparable electrical and thermal conductivity to solder with an increased operating range of strain and temperature. This paper documents the fabrication and experimental evaluation of a prototype conductive polymer nanocomposite. Material selection, fabrication processes, and initial characterization of a low Tg polymer with a high fill ratio of carbon nanotubes is presented. The electrical and thermal properties of the composite are measured and compared with predictions. The mechanical properties are measured using dynamic mechanical analysis (DMA over a wide temperature range. The mechanical and electrical responses of the conductive polymer composite are simultaneously measured at higher strain rates using a modified split Hopkinson pressure bar (SHPB apparatus. The dynamic stress-strain response is obtained using traditional analytic methods (e.g., two- and three-wave analysis. The electrical response is observed using constant current excitation with high bandwidth (>500?kHz instrumentation. The dynamic compression data implies the change in electrical resistance is solely a function of the material deformation, i.e., the material exhibits constant electrical conductivity and is insensitive to the applied loads. DMA and SHPB dynamic data are used to estimate the parameters in a Mulliken-Boyce constitutive model, and the resulting behavior is critically evaluated. Finally, progress towards improving the polymer composite's mechanical, electrical, and thermal properties are discussed.

  6. Rate dependence of electrical and mechanical properties of conductive polymer nanocomposites

    Science.gov (United States)

    Foley, J. R.; Stilson, C. L.; Smith, K. K. G.; McKinion, C. M.; Chen, C.; Ganguli, S.; Roy, A. K.

    2015-09-01

    Conductive polymer nanocomposites with enhanced electrical and thermal properties show promise as an alternative solution for electronic materials. For example, electronic interconnect materials will have comparable electrical and thermal conductivity to solder with an increased operating range of strain and temperature. This paper documents the fabrication and experimental evaluation of a prototype conductive polymer nanocomposite. Material selection, fabrication processes, and initial characterization of a low Tg polymer with a high fill ratio of carbon nanotubes is presented. The electrical and thermal properties of the composite are measured and compared with predictions. The mechanical properties are measured using dynamic mechanical analysis (DMA) over a wide temperature range. The mechanical and electrical responses of the conductive polymer composite are simultaneously measured at higher strain rates using a modified split Hopkinson pressure bar (SHPB) apparatus. The dynamic stress-strain response is obtained using traditional analytic methods (e.g., two- and three-wave analysis). The electrical response is observed using constant current excitation with high bandwidth (>500 kHz) instrumentation. The dynamic compression data implies the change in electrical resistance is solely a function of the material deformation, i.e., the material exhibits constant electrical conductivity and is insensitive to the applied loads. DMA and SHPB dynamic data are used to estimate the parameters in a Mulliken-Boyce constitutive model, and the resulting behavior is critically evaluated. Finally, progress towards improving the polymer composite's mechanical, electrical, and thermal properties are discussed.

  7. Surface Plasmon Resonance Sensing Detection of Mercury and Lead Ions Based on Conducting Polymer Composite

    OpenAIRE

    Mahnaz M. Abdi; Abdullah, Luqman Chuah; Sadrolhosseini, Amir R.; Mat Yunus, Wan Mahmood; Moksin, Mohd Maarof; Tahir, Paridah Md.

    2011-01-01

    A new sensing area for a sensor based on surface plasmon resonance (SPR) was fabricated to detect trace amounts of mercury and lead ions. The gold surface used for SPR measurements were modified with polypyrrole-chitosan (PPy-CHI) conducting polymer composite. The polymer layer was deposited on the gold surface by electrodeposition. This optical sensor was used for monitoring toxic metal ions with and without sensitivity enhancement by chitosan in water samples. The higher amounts of resonanc...

  8. Electrochemomechanical Behaviour of Bilayer and Trilayer Films with PEDOT and PPY Conducting Polymers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

    2008-01-01

    A detailed study on bilayer and trilayer films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers is reported. Both polymers are doped with dodecyl benzenesulfonate (DBS) anions. These multi layer films were prepared electrochemically so that the PEDOT layer is very thin compared to that of the PPy layer, and characterized using cyclic voltammetry, optical absorption spectroscopy and electrochemical quartz crystal microbalance (EQCM) techniques. Actu...

  9. Characterization of poly(3,4-ethylenedioxythiophene):tosylate conductive polymer microelectrodes for transmitter detection

    DEFF Research Database (Denmark)

    Larsen, Simon T.; Vreeland, Richard F.; Heien, Michael L.; Taboryski, Rafael J.

    2012-01-01

    In this paper we investigate the physical and electrochemical properties of micropatterned poly(3,4-ethylenedioxythiophene):tosylate (PEDOT:tosylate) microelectrodes for neurochemical detection. PEDOT:tosylate is a promising conductive polymer electrode material for chip-based bioanalytical applications such as capillary electrophoresis, high-performance liquid chromatography, and constant potential amperometry at living cells. Band electrodes with widths down to 3 ?m were fabricated on polymer ...

  10. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    DEFF Research Database (Denmark)

    Andresen, Kristian; Hansen, Morten; Matschuk, Maria; Jepsen, Søren Terpager; Sørensen, Henrik Schiøtt; Utko, Pawel; Selmeczi, Dávid; Hansen, Thomas Steen; Larsen, Niels Bent; Rozlosnik, Noemi; Taboryski, Rafael Jozef

    2010-01-01

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstra...

  11. Process for depositing strong adherend polymer coating onto an electrically conductive surface

    OpenAIRE

    Bertrand, Olivier; Jérôme, Robert; Gautier, Sandrine; Maquet, Véronique; Detrembleur, Christophe; Jérôme, Christine; Voccia, Samuel; Claes, Michaël; Lou, Xudong; Labaye, David-Emmanuel

    2002-01-01

    Process for depositing by electrografting a strong adherent polymer coating onto an electrically conductive surface comprising an electrochemical grafting at the surface of an active monomer for forming a primer coating P onto said surface and having as general formula: X0 (meth)acrylate wherein X is either part of a preformed polymer or is an intermediate agent for polyaddition reaction or is an anchoring group for attachment of a molecule having at least one complementary reactive group. Su...

  12. High Yield Sample Preconcentration Using a Highly Ion-conductive Charge-selective Polymer

    OpenAIRE

    Chun, Honggu; Chung, Taek Dong; Ramsey, J. Michael

    2010-01-01

    The development and analysis of a microfluidic sample preconcentration system using a highly ion-conductive charge-selective polymer (poly-AMPS) is reported. The preconcentration is based on the phenomenon of concentration polarization which develops at the boundaries of the poly-AMPS with buffer solutions. A negatively charged polymer, poly-AMPS, positioned between two microchannels efficiently extracts cations through its large cross section, resulting in efficient anion sample preconcentra...

  13. Fast prototyping of conducting polymer microelectrodes using resistance-controlled high precision drilling

    DEFF Research Database (Denmark)

    Kafka, Jan Robert; Geschke, Oliver; Skaarup, Steen; Larsen, Niels Bent

    2011-01-01

    We present a straightforward method for fast prototyping of microelectrode arrays in the highly conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Microelectrode arrays were produced by electrical resistance-controlled microdrilling through an insulating polymer layer (TOPAS® 5013) covering a PEDOT layer. The sudden drop in electrical resistance between the metal drill and the PEDOT layer upon physical contact was employed as stop criterion for the drilling process. Arrays of 3×3 micro...

  14. Microtexturing of the Conductive PEDOT:PSS Polymer for Superhydrophobic Organic Electrochemical Transistors

    OpenAIRE

    Francesco Gentile; Nicola Coppedè; Giuseppe Tarabella; Marco Villani; Davide Calestani; Patrizio Candeloro; Salvatore Iannotta; Enzo Di Fabrizio

    2014-01-01

    Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry an...

  15. Conducting polymers from aminobenzoic acids and aminobenzenesulphonic acids: influence of pH on electrochemical behaviour

    OpenAIRE

    Christopher M. A. Brett; Thiemann, Carolin

    2002-01-01

    The influence of pH on the electrochemical behaviour of conducting polymer films electrosynthesised from aminobenzoic acids and aminobenzenesulphonic acids was investigated by voltammetric and electrochemical impedance studies in sulphuric acid solution, acetate buffer and neutral phosphate buffer. The change in electrochemical behaviour with increasing pH is significantly less for poly(aminobenzenesulphonic acid)s and poly(aminobenzoic acid)s than for polyaniline. Polymer films made by elect...

  16. Sensing of environmental pollutant by conductive composite from prepared from hyperbranched polymer-grafted carbon black and crystalline polymer

    International Nuclear Information System (INIS)

    Complete text of publication follows. The hyperbranched (HB) polymer-grafted (PG) carbon blacks (CB) have the possibility of utilizing as a support of catalyst and enzyme, and a curing agent of epoxy resin, because they have much terminal amino or hydroxyl groups. The postgrafting of crystalline polymer onto HB PG CB and the sensing of environmental pollutant by the conductive composite prepared from the polymer-postgrafted CB was discussed. The grafting of poly(amidoamide) onto CB surface was achieved by repeating either Michael addition of methyl acrylate to amino group on the surface or the amidation of the resulting terminal methyl ester group with ethylene diamine. HB polyester onto CB surface was grafted by stepwise growth of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) from surface carboxyl and hydroxyl groups on CB as a core in the presence of p-toluenesulfonic acid (p-TSA). The one-pot grafting of HB polyester onto CB as core was also achieved by the polycondensation of bis-MPA in the presence of p-TSA. Postgrafting of crystalline polymer onto HB polymer-grafted CB was achieved by the reaction of terminal amino or hydroxyl groups of grafted chain with COCl-terminated crystalline polymer. The electric resistance of the composite prepared from crystalline polymer-postgrafted CB was found to increase drastically in hexane, containing environmental pollutant, such as chloroform and trichloroethane, and returned immediately to the initial resistance when it was transferred into pure hexane. Based on the above results, it is concluded that the composite can be used as a novel sensor for environmental pollutant in solution

  17. Effect of low energy oxygen ion beam irradiation on ionic conductivity of solid polymer electrolyte

    International Nuclear Information System (INIS)

    Over the past three decades, solid polymer electrolytes (SPEs) have drawn significant attention of researchers due to their prospective commercial applications in high energy-density batteries, electrochemical sensors and super-capacitors. The optimum conductivity required for such applications is about 10?2 – 10?4 S/cm, which is hard to achieve in these systems. It is known that the increase in the concentration of salt in the host polymer results in a continuous increase in the ionic conductivity. However, there is a critical concentration of the salt beyond which the conductivity decreases due to formation of ion pairs with no net charge. In the present study, an attempt is made to identify the concentration at which ion pair formation occurs in PEO: RbBr. We have attempted to modify microstructure of the host polymer matrix by low energy ion (Oxygen ion, O+1 with energy 100 keV) irradiation. Ionic conductivity measurements in these systems were carried out using Impedance Spectroscopy before and after irradiation to different fluencies of the oxygen ion. It is observed that the conductivity increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains. The study reveals the importance of ion irradiation as an effective tool to enhance conductivity in SPEs

  18. Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Yi.

    1991-10-07

    Several new types of silicon-containing preceramic polymers, i.e., poly(diorganosilacetylene) and poly(diorganosilvinylene) have been synthesized with molecular weights from 10,000 to 120,000. These polymers could be thermally converted to SiC with a moderate to high char yields. Ready solubility and good processability made these types of polymers attractive in their applications to ceramics. The thermal polymerization of diethynyldiphenyl-silane, which was reported in 1968 to afford poly(diphenylsilyldiacetylene) via dehydrogenation, was reinvestigated. Spectroscopic studies showed that the polymer had a structure of polyacetylene type not diacetylene. Diphenyldiethynylgermane and a series of diorganodiethynylsilances were synthesized. These could be polymerized in the presence of MoCl{sub 5} or WCl{sub 6} to afford a soluble, violet material with Mw as high as 108,000. 100 refs., 56 figs., 16 tabs.

  19. Effective Thermal Conductivity of Polymer Composites Using Local Fractal Techniques

    Directory of Open Access Journals (Sweden)

    Rajpal Singh Bhoopal,

    2013-02-01

    Full Text Available The model developed by Springer and Tsai is extended using non-linear volume fraction in place of physical porosity for the effective thermal conductivity of composite materials with the help of local fractal techniques. The expression for non-linear volume fraction is obtained using data available in the literature. Present model is constructed in terms of fiber volume fraction, the fiber-matrix thermal conductivity ratio and the local fractal dimensions. The effective thermal conductivity ratio is evaluated using the model with the approximation of the fractal dimensions. These fractal dimensions [PdandTd] are considered to be equal in the absence of information about the arrangement of fibers in the composites. The technique of local fractal dimensions is used to reduce the geometric complexity of the fiber arrangements. Better agreement of predicted effective thermal conductivity values with experimental results is obtained. A comparison with other models is also done and found that our model predict the values of effective thermal conductivity quite well.

  20. Coulomb Blockade in a Two-Dimensional Conductive Polymer Monolayer

    Science.gov (United States)

    Akai-Kasaya, M.; Okuaki, Y.; Nagano, S.; Mitani, T.; Kuwahara, Y.

    2015-11-01

    Electronic transport was investigated in poly(3-hexylthiophene-2,5-diyl) monolayers. At low temperatures, nonlinear behavior was observed in the current-voltage characteristics, and a nonzero threshold voltage appeared that increased with decreasing temperature. The current-voltage characteristics could be best fitted using a power law. These results suggest that the nonlinear conductivity can be explained using a Coulomb blockade (CB) mechanism. A model is proposed in which an isotropic extended charge state exists, as predicted by quantum calculations, and percolative charge transport occurs within an array of small conductive islands. Using quantitatively evaluated capacitance values for the islands, this model was found to be capable of explaining the observed experimental data. It is, therefore, suggested that percolative charge transport based on the CB effect is a significant factor giving rise to nonlinear conductivity in organic materials.

  1. Hybrid polymer:colloidal nanoparticle photovoltaic cells incorporating a solution-processed, multi-functioned ZnO nanocrystal layer

    Science.gov (United States)

    Yang, Jihua; Qian, Lei; Zhou, Renjia; Zheng, Ying; Tang, Aiwei; Holloway, Paul H.; Xue, Jiangeng

    2012-02-01

    We report significant improvement in both the power conversion efficiency and the environmental stability of solution-processed hybrid organic-inorganic solar cells by including a solution-processed ZnO nanocrystal layer between the photoactive layer and the cathode. For devices based on blends of poly(3-hexylthiophene) (P3HT) and mostly-spherical CdSe nanocrystals, incorporation of the ZnO layer leads to an up to 70% increase in the power conversion efficiency. Compared to only a few hours of shelf lifetime for unencapsulated devices with the metal cathode directly deposited on the hybrid active layer, devices with the ZnO layer can retain approximately 70% of the original efficiency when they are exposed to the laboratory ambient without encapsulation for more than two months. We attribute the function of this ZnO nanocrystal layer to a combination of optical, electronic, morphological, and chemical effects, including blocking leakage of photogenerated holes to the cathode, optimizing the optical intensity profile in the hybrid active layer, minimizing recombination or quenching of photogenerated excitons and charge carriers, significantly reducing the transport rate of oxygen and water molecules to the active layer and reducing degradation/oxidation of any low work function layer at the cathode interface.

  2. Modification of Conductive Polymer for Polymeric Anodes of Flexible Organic Light-Emitting Diodes

    OpenAIRE

    Wang Guang-Feng; Tao Xiao-Ming; Xin John; Fei Bin

    2009-01-01

    Abstract A conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), was modified with dimethyl sulfoxide (DMSO) in solution state, together with sub-sequential thermal treatment of its spin-coated film. The electrical conductivity increased by more than three orders of magnitude improvement was achieved. The mechanism for the conductivity improvement was studied at nanoscale by particle size analysis, field emission scanning electron microscopy (FESEM), and X-...

  3. Structure-conductivity studies in polymer electrolytes containing multivalent cations

    CERN Document Server

    Aziz, M

    1996-01-01

    force microscopy (AFM). DSC evidences helped to explain the texture of the iron samples during the drying process, and showed transitions between low melting, PEO and high melting spherulites, and VTPM is able to visualise the spherulites present in the samples. AFM has successfully imaged the as cast PEO sub 8 :FeBr sub 2 sample and the surface effect causing extra resistance in the impedance spectra could be seen. Conductivity studies were carried out using a.c. impedance spectra. Fe(ll) samples exhibit the typical semicircle-spike plot but the Fe(lll) samples displayed an extra semicircle before the spike reflecting a surface effect. This is also manifested in the Arrhenius plots of the same samples where a dip was shown at 100 deg C. From the conductivity studies on the iron systems it was found that for the dry samples the optimum conductivity was observed in PEO sub 8 :FeBr sub x irrespective of the valence state of the cation. For the air-cast samples the optimum conductivity composition depends on the...

  4. Thermally stimulated discharge conductivity in polymer composite thin films

    Indian Academy of Sciences (India)

    V S Sangawar; P S Chikhalikar; R J Dhokne; A U Ubale; S D Meshram

    2006-08-01

    This paper describes the results of thermally stimulated discharge conductivity study of activated charcoal–polyvinyl chloride (PVC) thin film thermoelectrets. TSDC has been carried out in the temperature range 308–400°K and at four different polarizing fields. Results are discussed on the basis of mobility of activated charcoal and polyvinyl chloride chains.

  5. Tunnelling conductivity in conducting polymer composites: a manifestation of chemical interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kalasad, M N; Rabinal, M K, E-mail: mkrabinal@yahoo.co [Department of Physics, Karnatak University, Dharwad-580003, Karnataka State (India)

    2009-03-21

    Charge transport is studied in conducting composites of polyaniline and cis-1,4-polyisoprene (rubber). Films of different compositions are prepared by the solution route that are easily compressible under low pressure. Electrical conductivity is measured across the film thickness with the applied pressure. The results clearly indicate that conductivity is dominated by quantum tunnelling of charge carriers between conducting particles through an insulating barrier for all compositions. These findings are attributed to a strong chemical interaction between the conducting and non-conducting phases. It is demonstrated that such chemical interaction is a vital phenomenon in controlling charge transport of composites.

  6. Gamma Radiation Induced Preparation of Functional Conducting Polymer Hollow Spheres

    International Nuclear Information System (INIS)

    New materials are sought for applications in many of the emerging fields that include catalysis, sensors, biomedical, optics and electronic application. With the advent of nanotechnology, innovative materials with novel properties are being synthesized towards target applications. Changing the sizes of particles, chemical, optical, and mechanical properties of the materials can often be tailored according to the specific needs of the application. Nanocrystalline, nanoparticles, nanocapsules, nanoporous materials, nanofibers, nanowires, fullerenes, nanotubes, nanosprings, nanobelts, dendrimers and nanospheres, ets, are few of the nanostructured materials. The examples of nanostructured materials include semiconducting nanowire quantum dots for gas sensing and self-assembled flower-like architectures. Self-assembly of nanoparticles can result in specific structures with unique and useful electronic, optical, and magnetic properties. Self or induced assemby of simple nanoparticles and rods could result into complex geometries, such as nanoflowers, binary superlattices, optical grating. Over the past decade, hollow spherical nanomaterials have received considerable attention due to their interesting properties such as low density, high surface area and good permeation. Various methods like solvothermal, self-assembly, sonochemical, solvent evaporation, chemical vapor deposition, microwave-assisted aqueous hydrothermal and electrochemical are being pursued for the production of hollow spherical materials. Polymer capsules and hollow spheres have increasingly received interest because of their large surface area and potential applications in catalysis, controlled delivery, artificial cells, light fillers and photonics

  7. Computational modeling of the thermal conductivity of single-walled carbon nanotube-polymer composites

    International Nuclear Information System (INIS)

    A computational model was developed to study the thermal conductivity of single-walled carbon nanotube (SWNT)-polymer composites. A random walk simulation was used to model the effect of interfacial resistance on the heat flow in different orientations of SWNTs dispersed in the polymers. The simulation is a modification of a previous model taking into account the numerically determined thermal equilibrium factor between the SWNTs and the composite matrix material. The simulation results agreed well with reported experimental data for epoxy and polymethyl methacrylate (PMMA) composites. The effects of the SWNT orientation, weight fraction and thermal boundary resistance on the effective conductivity of composites were quantified. The present model is a useful tool for the prediction of the thermal conductivity within a wide range of volume fractions of the SWNTs, so long as the SWNTs are not in contact with each other. The developed model can be applied to other polymers and solid materials, possibly even metals

  8. Individually addressable crystalline conducting polymer nanowires in a microelectrode sensor array

    International Nuclear Information System (INIS)

    An efficient, site-specific and scalable approach has been developed to produce high-quality and individually addressable conducting polymer nanowire electrode junctions (CPNEJs) in a parallel-oriented array. Polypyrrole and PEDOT conducting polymer nanowires (CPNWs) with uniform diameters (ca. 60-150 nm) were introduced into the desired electrode junctions in a precise manner by performing a three-step constant-current electrochemical process at a low current density and a low concentration of monomers. A low scan rate, cyclic voltammetric method was also employed and gave similar results. These CPNEJ arrays function as a miniaturized sensor for the parallel and real-time detection of gas and organic vapour. The electrochemical approaches utilized allow the conducting polymer chains to self-organize in the CPNWs to form novel polycrystalline structures, observed by high resolution TEM. The weak diffraction rings at 4.88 A and 4.60 A were observed for PEDOT and polypyrrole CPNWs, respectively

  9. Electrochemical synthesis of electronic and ionic conductive polymer composite polyaniline/PEO network

    International Nuclear Information System (INIS)

    A bilayer composite of conducting polyaniline was prepared by electrochemical polymerization of anilinium salt (dissolved in appropriate solvent like DMF, methanol, or water) in poly(ethylene oxide) PEO network. When washed, dried and doped with LiClO4, the bilayer showed electro-chemical activity corresponding to doping and undoping reactions in the solid state. The bilayer was characterized by FT-IR (reflection), UV spectroscopy and microscopic examination while the electrochemical activity in the solid state was examined by cyclic voltammetry. Cyclic voltammetry of the composite conductive polymer and polymer electrolyte in the solid state against Pt produced oxidation peaks at 0.26 and 0.78 V. Against Li, a broad oxidation peak appeared between 0.5 and 4.5; doping efficiency in the Li cell reached 95% between 2-4 V at a scan rate of 100 mV/s. The color of the conducting polymer as anode changed from transparent yellow to green and then to blue during the doping process. Cole-cole plots of the composite obtained by AC impedance measurements showed an arc at high frequency region (>2.82 MHx) due to polymer electrolyte impedance. Another arc due to impedance of the doping reaction, at lower frequency (>20 Hz) followed as doping of the conductive polymer preceeded; the arc is then joined by a Warburg line, which characterizes diffusion controlled kinetics at the low frequency region (<20 Hz). (auth.). 17 refs.; 14 figs. 2 tabs

  10. Conductivity behavior of very thin gold films ruptured by mass transport in photosensitive polymer film

    International Nuclear Information System (INIS)

    We report on conductivity behavior of very thin gold layer deposited on a photosensitive polymer film. Under irradiation with light interference pattern, the azobenzene containing photosensitive polymer film undergoes deformation at which topography follows a distribution of intensity, resulting in the formation of a surface relief grating. This process is accompanied by a change in the shape of the polymer surface from flat to sinusoidal together with a corresponding increase in surface area. The gold layer placed above deforms along with the polymer and ruptures at a strain of 4%. The rupturing is spatially well defined, occurring at the topographic maxima and minima resulting in periodic cracks across the whole irradiated area. We have shown that this periodic micro-rupturing of a thin metal film has no significant impact on the electrical conductivity of the films. We suggest a model to explain this phenomenon and support this by additional experiments where the conductivity is measured in a process when a single nanoscopic scratch is formed with an AFM tip. Our results indicate that in flexible electronic materials consisting of a polymer support and an integrated metal circuit, nano- and micro cracks do not alter significantly the behavior of the conductivity unless the metal is disrupted completely

  11. Novel conducting polymer-heteropoly acid hybrid material for artificial photosynthetic membranes.

    Science.gov (United States)

    McDonald, Michael B; Freund, Michael S

    2011-04-01

    Artificial photosynthetic (AP) approaches to convert and store solar energy will require membranes capable of conducting both ions and electrons while remaining relatively transparent and chemically stable. A new approach is applied herein involving previously described in situ chemical polymerization of electronically conducting poly(3,4-ethylenedioxythiophene) (PEDOT) in the presence of proton conducting heteropoly acid (HPA) phosphomolybdic acid (PMA). The electrochemical behaviour of the PEDOT/PMA hybrid material was investigated and it was found that the conducting polymer (CP) is susceptible to irreversible oxidative processes at potentials where water is oxidized. This will be problematic in AP devices should the process occur in very close proximity to a conducting polymer-based membrane. It was found that PEDOT grants the system good electrical performance in terms of conductivity and stability over a large pH window; however, the presence of PMA was not found to provide sufficient proton conductivity. This was addressed in an additional study by tuning the ionic (and in turn, electronic) conductivity in creating composites with the proton-permselective polymer Nafion. It was found that a material of this nature with near-equal conductivity for optimal chemical conversion efficiency will consist of roughly three parts Nafion and one part PEDOT/PMA. PMID:21384827

  12. Electron-donor dopant, method of improving conductivity of polymers by doping therewith, and a polymer so treated

    Energy Technology Data Exchange (ETDEWEB)

    Liepins, R.; Aldissi, M.

    1984-07-27

    Polymers with conjugated backbones, both polyacetylene and polyaromatic heterocyclic types, are doped with electron-donor agents to increase their electrical conductivity. The electron-donor agents are either electride dopants made in the presence of lithium or dopants derived from alkalides made in the presence of lithium. The dopants also contain a metal such as cesium and a trapping agent such as a crown ether.

  13. Electron-donor dopant, method of improving conductivity of polymers by doping therewith, and a polymer so treated

    Energy Technology Data Exchange (ETDEWEB)

    Liepins, Raimond (Los Alamos, NM); Aldissi, Mahmoud (Los Alamos, NM)

    1988-01-01

    Polymers with conjugated backbones, both polyacetylene and polyaromatic heterocyclic types, are doped with electron-donor agents to increase their electrical conductivity. The electron-donor agents are either electride dopants made in the presence of lithium or dopants derived from alkalides made in the presence of lithium. The dopants also contain a metal such as cesium and a trapping agent such as a crown ether.

  14. Tattoo conductive polymer nanosheets for skin-contact applications.

    Science.gov (United States)

    Zucca, Alessandra; Cipriani, Christian; Sudha; Tarantino, Sergio; Ricci, Davide; Mattoli, Virgilio; Greco, Francesco

    2015-05-01

    Conductive tattoo nanosheets are fabricated on top of decal transfer paper and transferred on target surfaces as temporary transfer tattoos. Circuits are patterned with ink-jet printing. Tattoo nanosheets are envisioned as unperceivable human-device interfaces because of conformal adhesion to complex surfaces including skin. They are tested as dry electrodes for surface electromyography (sEMG), which permits the control of a robotic hand. PMID:25702914

  15. Study of Swift Heavy Ion Modified Conducting Polymer Composites for Application as Gas Sensor

    Directory of Open Access Journals (Sweden)

    Ulrich W. Scherer

    2006-04-01

    Full Text Available A polyaniline-based conducting composite was prepared by oxidativepolymerisation of aniline in a polyvinylchloride (PVC matrix. The coherent free standingthin films of the composite were prepared by a solution casting method. The polyvinylchloride-polyaniline composites exposed to 120 MeV ions of silicon with total ion fluenceranging from 1011 to 1013 ions/cm2, were observed to be more sensitive towards ammoniagas than the unirradiated composite. The response time of the irradiated composites wasobserved to be comparably shorter. We report for the first time the application of swiftheavy ion modified insulating polymer conducting polymer (IPCP composites for sensingof ammonia gas.

  16. Nanofiber preparation by whisker method using solvent-soluble conducting polymers

    International Nuclear Information System (INIS)

    We prepared conducting polymer nanofibers by means of whisker formation in a solution by using solvent-soluble conducting polymers with alkyl or alkoxy side chains. A morphological characterization using an atomic force microscope indicated that they have one-dimensional nanofibrillar structures with typical heights of 3-10 nm. The conductivity of a single poly(3-hexylthiophene) (P3HT) nanofiber was measured using 300-nm-spacing Pt electrodes and the conductivity of 0.25 S/cm at 290 K was achieved by chemical doping using nitrosonium tetrafluoroborate. Considering the temperature dependence of the conductivity, the carrier transport in the single nanofiber was explained by a quasi-one-dimensional variable range-hopping model

  17. Controlled Aloin Release from Crosslinked Polyacrylamide Hydrogels: Effects of Mesh Size, Electric Field Strength and a Conductive Polymer

    OpenAIRE

    Anuvat Sirivat; Amornrat Niansiri; Sumonman Niamlang; Tawansorn Buranut

    2013-01-01

    The aim of this paper is to investigate the effects of hydrogel mesh size, a conductive polymer, and electric field strength on controlled drug delivery phenomena using drug-loaded polyacrylamide hydrogels prepared at various crosslinking ratios both with and without a conductive polymer system. Poly(p-phenylene vinylene), PPV, as the model conductive polymer, was used to study its ability to control aloin released from aloin-doped poly(p-phenylene vinylene)/polyacrylamide hydrogel (aloin-dop...

  18. Reversible shape memory of nanoscale deformations in inherently conducting polymers without reprogramming.

    Science.gov (United States)

    Higgins, Michael J; Grosse, Willo; Wagner, Klaudia; Molino, Paul J; Wallace, Gordon G

    2011-04-01

    By using inherently conducting polymers, we introduce new shape memory functionality for stimuli-responsive polymers. The shape memory process is unique in that it utilizes electrochemical control of the polymer redox state to conceal, and temporarily store, preformed nanoscale surface patterns, which can later be recalled. Unlike classical thermoset and thermoplastic shape memory polymers, the electrochemical control does not completely perturb the low entropy state of the deformed polymer chains, thus enabling the concept of reversible transition between the permanent and temporary shapes. This is demonstrated using electrochemical-atomic force microscopy/quartz crystal microbalance to characterize the modulation of nanoscale deformations in electroactive polybithiophene films. Experimental results reveal that cation/solvent exchange with the electrolyte and its effect on reconfiguration of the film structure is the mechanism behind the process. In addition to incorporating conductive properties into shape-memory polymers, the ability to reversibly modulate surface nanopatterns in a liquid environment is also of significant interest in tribology and biointerface applications. PMID:21401135

  19. Facile preparation of transparent and conductive polymer films based on silver nanowire/polycarbonate nanocomposites.

    Science.gov (United States)

    Moreno, Ivan; Navascues, Nuria; Arruebo, Manuel; Irusta, Silvia; Santamaria, Jesus

    2013-07-12

    Silver nanowires (AgNW) synthesized by a solvothermal method were incorporated into a polycarbonate matrix by a solution mixing procedure. Films with a thickness around 18 ?m were obtained, showing a good distribution of the wires within the polymer matrix. The thermal stability of the polymer matrix increased significantly, with the main decomposition peak shifting up to 74 ° C for an AgNW loading of 4.35 wt%. The percolation threshold was obtained at very low AgNW content (0.04 wt%), and the composite electrical conductivity at the maximum loading (4.35 wt%) was 41.3 ? cm. Excellent transparency was obtained at the percolation threshold, with negligible reduction in the transmittance of the polymer matrix (from 88.2 to 87.6% at 0.04 wt% loading of AgNW). In addition, the polymer matrix protected the silver nanowires from oxidation, as demonstrated by the XPS analysis. PMID:23743565

  20. Facile preparation of transparent and conductive polymer films based on silver nanowire/polycarbonate nanocomposites

    International Nuclear Information System (INIS)

    Silver nanowires (AgNW) synthesized by a solvothermal method were incorporated into a polycarbonate matrix by a solution mixing procedure. Films with a thickness around 18 ?m were obtained, showing a good distribution of the wires within the polymer matrix. The thermal stability of the polymer matrix increased significantly, with the main decomposition peak shifting up to 74?° C for an AgNW loading of 4.35 wt%. The percolation threshold was obtained at very low AgNW content (0.04 wt%), and the composite electrical conductivity at the maximum loading (4.35 wt%) was 41.3 ? cm. Excellent transparency was obtained at the percolation threshold, with negligible reduction in the transmittance of the polymer matrix (from 88.2 to 87.6% at 0.04 wt% loading of AgNW). In addition, the polymer matrix protected the silver nanowires from oxidation, as demonstrated by the XPS analysis. (paper)

  1. Selective sensing of volatile organic compounds using novel conducting polymer-metal nanoparticle hybrids

    International Nuclear Information System (INIS)

    Conducting polymer-metal nanoparticle hybrids, fabricated by assembling metal nanoparticles on top of functionalized conducting polymer film surfaces using conjugated linker molecules, enable the selective sensing of volatile organic compounds (VOCs). In these conducting polymer-metal nanoparticle hybrids, selectivity is achieved by assembling different metals on the same conducting polymer film. This eliminates the need to develop either different polymers chemistries or device configurations for each specific analyte. In the hybrids, chemisorption of the analyte vapor induces charge redistribution in the metal nanoparticles and changes their work function. The conjugated linker molecule causes this change in the work function of the tethered nanoparticles to affect the electronic states in the underlying conducting polymer film. The result is an easily measurable change in the resistance of the hybrid structure. The fabrication of these sensing elements involved the covalent assembly of nickel (Ni) and palladium (Pd) metal nanoparticles on top of poly(3,4-ethylenedioxythiophene-co-thiophene-3-acetic acid), poly(EDOT-co-TAA), films using 4-aminothiophenol linker molecules. The change in resistance of hybrid Pd/poly(EDOT-co-TAA) and Ni/poly(EDOT-co-TAA) hybrid films to acetone and toluene, respectively, is observed to be in proportion to their concentrations. The projected detection limits are 2 and 10 ppm for toluene and acetone, respectively. A negligible response (resistance change) of the Pd/poly(EDOT-co-TAA) films to toluene exposure confirmed its selectivity for detecting acetone. Similarly, lack of response to acetone confirmed the selectivity of the Ni/poly(EDOT-co-TAA) stacks for detecting toluene. It is anticipated that the assembly of other metals such as Ag, Au and Cu on top of poly(EDOT-co-TAA) would provide selectivity for detecting and discriminating other VOCs.

  2. Graphene-polyethylenedioxythiophene conducting polymer nanocomposite based supercapacitor

    International Nuclear Information System (INIS)

    Graphical abstract: Schematic diagrams of an electrochemical double layer type capacitor showing the charged (left) and discharged (right) states. Highlights: ? The Graphene-PEDOT nanocomposite based smart coating has shown the excellent redox properties in acidic, organic electrolytes, which is promising for suprecapcitor application. ? The electrochemical impedance studies have also been estimated which clearly indicates the high conductivity and less charge transfer resistance in the synthesized material. ? The specific capacitance of 380F/g have been calculated for G-Pedot material, also it shows the columbic efficiency of 95% for 800 cycles, which tells the remarkable stability of synthesized material. - Abstract: We present here the synthesis, characterization and application of graphene (G)-polyethylenedioxythiophene (PEDOT) nanocomposites as electrode material for supercapacitor applications. The G-PEDOT nanocomposite was synthesized using a chemical oxidative polymerization technique, and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, FTIR spectroscopy, X-ray-diffraction, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) techniques. The electrochemical charge/discharge characteristics of G-PEDOT nanocomposites were investigated in different electrolytic media, and the specific discharge capacitance was estimated to be 374 Farad/gram (F/gm). This manuscript presents the capacitance studies on supercapacitor G-PEDOT electrode with respect to stability of material, specific capacitance, electrical conductivity and specific charge/discharge properties of the supercapacitor electrodes. Our study has revealed that the G-PEDOT nanocomposite could be a transformable and viable electrode material for supercapacitor applications.

  3. Observation of irreversible current path in polymer dielectric using conductive atomic force microscope

    Science.gov (United States)

    Jung, Ji-Hoon; Kim, Woo Young; Kim, Do-Kyung; Kwon, Jin-Hyuk; Lee, Hee Chul; Bae, Jin-Hyuk

    2015-03-01

    During the measurement of the electrical properties of a metal-polymer-metal capacitor, it was found that the capacitor exhibited write-once-read-many-times (WORM) memory behavior, even though it was made of the dielectric polymer, polystyrene. The initial low conductance state changed to a high conductance state when a threshold voltage was applied, but this final state never reverted to the initial state. This phenomenon only appeared in sub-100-nm-thick films. To understand this phenomenon, conductive atomic force microscopy (CAFM) was used. The current distribution measured with CAFM showed an irreversible current path had formed near particles in the polymer film. For reproducibility, particles were intentionally inserted into the polymer film during the fabrication of metal-polymer-metal capacitors, and the same current mechanism was found. From these results, it is concluded that the purification and cleaning process of organic devices severely affects the device characteristics. In addition, particle-insertion appears to be a promising method for fabrication low-cost and air-stable WORM type memory for various applications. [Figure not available: see fulltext.

  4. Conductivity studies of LiCF{sub 3}SO{sub 3} doped PVA: PVdF blend polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Tamilselvi, P.; Hema, M., E-mail: mhema2006@gmail.com

    2014-03-15

    Different composition of lithium ion conducting PVA: PVdF: Lithium triflate (LiCF{sub 3}SO{sub 3}) polymer electrolytes have been prepared by solution casting technique. Dielectric and conductivity studies have been carried out for the prepared samples. The addition of salt into the polymer matrix increases the ionic conductivity of blend polymer electrolytes. The conductivity analysis reveals 80PVA: 20PVdF: 15LiCF{sub 3}SO{sub 3} polymer electrolyte exhibits the maximum ionic conductivity of 2.7×10{sup ?3} S cm{sup ?1} at 303 K. The temperature dependence of ionic conductivity for all the composition of PVA: PVdF: LiCF{sub 3}SO{sub 3} polymer films obey Arrhenius relation. Low activation energy has been obtained for highest conducting sample. The dielectric spectra show absolute ?-relaxation peak.

  5. Conductivity studies of LiCF3SO3 doped PVA: PVdF blend polymer electrolyte

    International Nuclear Information System (INIS)

    Different composition of lithium ion conducting PVA: PVdF: Lithium triflate (LiCF3SO3) polymer electrolytes have been prepared by solution casting technique. Dielectric and conductivity studies have been carried out for the prepared samples. The addition of salt into the polymer matrix increases the ionic conductivity of blend polymer electrolytes. The conductivity analysis reveals 80PVA: 20PVdF: 15LiCF3SO3 polymer electrolyte exhibits the maximum ionic conductivity of 2.7×10?3 S cm?1 at 303 K. The temperature dependence of ionic conductivity for all the composition of PVA: PVdF: LiCF3SO3 polymer films obey Arrhenius relation. Low activation energy has been obtained for highest conducting sample. The dielectric spectra show absolute ?-relaxation peak

  6. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    Directory of Open Access Journals (Sweden)

    Qiong Nian

    2015-06-01

    Full Text Available Commercial production of transparent conducting oxide (TCO polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC of solution deposited aluminium-doped zinc oxide (AZO nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm2 V?1 s?1 with corresponding electrical resistivity and sheet resistances as low as 1 × 10?3 ? cm and 75 ?/sq, respectively. The high mobility also enabled a high transmittance (T of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods.

  7. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    Science.gov (United States)

    Nian, Qiong; Callahan, Michael; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-06-01

    Commercial production of transparent conducting oxide (TCO) polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC) of solution deposited aluminium-doped zinc oxide (AZO) nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm2 V-1 s-1 with corresponding electrical resistivity and sheet resistances as low as 1 × 10-3 ? cm and 75 ?/sq, respectively. The high mobility also enabled a high transmittance (T) of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods.

  8. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    International Nuclear Information System (INIS)

    Commercial production of transparent conducting oxide (TCO) polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC) of solution deposited aluminium-doped zinc oxide (AZO) nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm2 V?1 s?1 with corresponding electrical resistivity and sheet resistances as low as 1 × 10?3 ? cm and 75 ?/sq, respectively. The high mobility also enabled a high transmittance (T) of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods

  9. Large enhancement in neurite outgrowth on a cell membrane-mimicking conducting polymer

    Science.gov (United States)

    Zhu, Bo; Luo, Shyh-Chyang; Zhao, Haichao; Lin, Hsing-An; Sekine, Jun; Nakao, Aiko; Chen, Chi; Yamashita, Yoshiro; Yu, Hsiao-Hua

    2014-07-01

    Although electrically stimulated neurite outgrowth on bioelectronic devices is a promising means of nerve regeneration, immunogenic scar formation can insulate electrodes from targeted cells and tissues, thereby reducing the lifetime of the device. Ideally, an electrode material capable of electrically interfacing with neurons selectively and efficiently would be integrated without being recognized by the immune system and minimize its response. Here we develop a cell membrane-mimicking conducting polymer possessing several attractive features. This polymer displays high resistance towards nonspecific enzyme/cell binding and recognizes targeted cells specifically to allow intimate electrical communication over long periods of time. Its low electrical impedance relays electrical signals efficiently. This material is capable to integrate biochemical and electrical stimulation to promote neural cellular behaviour. Neurite outgrowth is enhanced greatly on this new conducting polymer; in addition, electrically stimulated secretion of proteins from primary Schwann cells can also occur on it.

  10. Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes

    Directory of Open Access Journals (Sweden)

    Cristiane M. Becker

    2012-01-01

    Full Text Available The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the content of acid polar groups incorporated into the macromolecular chain. Polymeric films were produced by blending the sulfonated styrene-indene copolymer with poly(vinylidene fluoride. The degree of sulfonation of the polymer was strongly affected by the sulfonation reaction parameters, with a direct impact on the ionic exchange capacity and the ionic conductivity of the sulfonated polymers and the membranes obtained from them. The films produced with the blends showed more suitable mechanical properties, although the conductivity of the membranes was still lower than that of commercially available membranes used in fuel cells.

  11. Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes

    Scientific Electronic Library Online (English)

    Cristiane M., Becker; Amanda B., Biagini; Maria M. C., Forte; Sandro C., Amico; José V. C., Vargas; Denise S., Azambuja.

    Full Text Available The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the conten [...] t of acid polar groups incorporated into the macromolecular chain. Polymeric films were produced by blending the sulfonated styrene-indene copolymer with poly(vinylidene fluoride). The degree of sulfonation of the polymer was strongly affected by the sulfonation reaction parameters, with a direct impact on the ionic exchange capacity and the ionic conductivity of the sulfonated polymers and the membranes obtained from them. The films produced with the blends showed more suitable mechanical properties, although the conductivity of the membranes was still lower than that of commercially available membranes used in fuel cells.

  12. Conductivity enhancement via chemical modification of chitosan based green polymer electrolyte

    International Nuclear Information System (INIS)

    The potential of carboxymethyl chitosan as a green polymer electrolyte has been explored. Chitosan produced from partial deacetylation of chitin was reacted with monochloroacetic acid to form carboxymethyl chitosan. A green polymer electrolyte based chitosan and carboxymethyl chitosan was prepared by solution-casting technique. The powder and films were characterized by reflection Fourier transform infrared (ATR-FTIR) spectroscopy, 1H nuclear magnetic resonance, elemental analysis and X-ray diffraction, electrochemical impedance spectroscopy, and scanning electron microscopy. The shift of wavenumber that represents hydroxyl and amine stretching confirmed the polymer solvent complex formation. The XRD spectra results show that chemical modification of chitosan has improved amorphous properties of chitosan. The ionic conductivity was found to increase by two magnitudes higher with the chemical modification of chitosan. The highest conductivity achieved was 3.6 × 10?6 S cm?1 for carboxymethyl chitosan at room temperature and 3.7 × 10?4 S cm?1 at 60 °C

  13. Electric conductivity of solid-phase mixtures polymer-tungstophosphoric acid

    International Nuclear Information System (INIS)

    The results of study of electric conductivity of composite materials based on polymer (polyvinyl alcohol (PVA) and fluoroplastic) and tungstophosphoric acid (TPA) are presented. The measurements were conducted at room temperature (20±3 deg C) and alternating current in the 1-50 kHz frequency range. It is shown that introduction into fluoroplastic composition results in a monotonous decrease of electric conductivity. The dependence of electric conductivity on composition for the TPA-PVA system includes two parts and reflects chemical interaction in the solid phase. An analytical form of the composition of double-composite mixtures is derived

  14. Ionic Conductivity and Dielectric Properties of the PAN-Ion Conducting Polymers

    Science.gov (United States)

    Isa, K. B. Md.; Ali, N. M.; Othman, L.; Ahmad, A.; Osman, Z.

    2008-05-01

    In this work, the ion conducting films of polyacrylonitrile (PAN) containing plasticizer and dopant salts were prepared by the solution casting technique. The salts selected for this study are lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3). The ionic conductivity measurements were carried out using impedance spectroscopy. The room temperature conductivity for pure polyacrylonitrile film is 1.51×10-11 S cm-1. The room temperature conductivity for the highest conducting film in the PAN-LiCF3SO3 system and the PAN-NaCF3SO3 system is 3.04×10-4 and 7.13×10-4 S cm-1, respectively. The conductivity-temperature studies were performed in the temperature range between 303 K and 373 K. The variation of the conductivity with temperature is obeys the Arrhenius rule. The increase and decrease in the number of ions can be implied from the plots of dielectric constant, ?r-frequency and dielectric loss, ?i-frequency.

  15. Microwave synthesis: An alternative approach to synthesize conducting end-capped polymers.

    Czech Academy of Sciences Publication Activity Database

    Marcasuzaa, P.; Reynaud, S.; Grassl, B.; Preud’homme, H.; Desbrieres, J.; Trchová, Miroslava; Donard, O. F. X.

    2011-01-01

    Ro?. 52, ?. 1 (2011), s. 33-39. ISSN 0032-3861 Grant ostatní: Eco-net project(FR) 16256SA Institutional research plan: CEZ:AV0Z40500505 Keywords : tetra-aniline * microwave synthesis * intrinsically conducting polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.438, year: 2011

  16. THE ELECTROCHEMISTRY OF ANTIBODY-MODIFIED CONDUCTING POLYMER ELECTRODES. (R825323)

    Science.gov (United States)

    AbstractThe modification of conducting polymer electrodes with antibodies (i.e. proteins) by means of electrochemical polymerization is a simple step that can be used to develop an immunological sensor. However, the electrochemical processes involved leading to the ge...

  17. Integration of microwave MEMS devices into rectangular waveguide with conductive polymer interposers

    OpenAIRE

    Baghchehsaraei, Zargham; Sterner, Mikael; Åberg, Jan; Oberhammer, Joachim

    2013-01-01

    This paper investigates a novel method of integrating microwave microelectromechanical systems (MEMS) chips into millimeter-wave rectangular waveguides. The fundamental difficulties of merging micromachined with macromachined microwave components, in particular, surface topography, roughness, mechanical stress points and air gaps interrupting the surface currents, are overcome by a double-side adhesive conductive polymer interposer. This interposer provides a uniform electrical contact, stabl...

  18. Photomodulation spectroscopy of photocarrier dynamics, electronic defects and morphology of conducting polymers

    International Nuclear Information System (INIS)

    A variety of techniques were used: CW photomodulation, photomodulation in femtosecond and picosecond time ranges, CW resonant Raman scattering, transient photoinduced Raman scattering, electro-absorption, degenerate four-wave mixing, spin dependent photomodulation, and absorption detected magnetic resonance. The following conducting polymers were studied: polyacetylene, polythiophene, polydiacetylene 4-BCMU, polydiethynylsilanes, polysilane embedded in a-Si:H matrix, and fullerenes

  19. Conducting polymer and ionic liquid: improved thermal stability of the material - a spectroscopic study.

    Czech Academy of Sciences Publication Activity Database

    Trchová, Miroslava; Šed?nková, Ivana; Morávková, Zuzana; Stejskal, Jaroslav

    2014-01-01

    Ro?. 109, November (2014), s. 27-32. ISSN 0141-3910 R&D Projects: GA ?R GAP205/12/0911 Institutional support: RVO:61389013 Keywords : polyaniline * conducting polymer * ionic liquid Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.163, year: 2014

  20. Carbon nanotubes with silver nanoparticle decoration and conductive polymer coating for improving the electrical conductivity of polycarbonate composites

    KAUST Repository

    Patole, Archana S.

    2015-01-01

    We proposed a strategy to enhance the conductivity of polycarbonate by using three-phase hybrid metallic/non-metallic fillers. Ethylene diamine (EDA) functionalized multiwalled carbon nanotubes (MWCNT-EDA) are first decorated with silver nanoparticles. These Ag/ MWCNT-EDA fillers are then coated with a conductive layer of ethylene glycol treated PEDOT: PSS (poly [3,4-ethylenedioxythiophene]: poly [styrenesulfonate]) (EP). In such an approach, the MWCNT backbone is covered by a highly conductive coating made of Ag nanoparticles surrounded by EP. To understand how Ag and EP form a highly conductive coating, the effect of different wt% of Ag nanoparticles on EP was studied. Ag nanoparticles around the size of 128 ± 28 nmeffectively lowered the volume resistivity of bulk EP, resulting in a highly conducting Ag/EP blend. We found that in the final Ag/MWCNT-EDA/EP assembly, the EP coating enhances the electrical conductivity in two ways: (1) it is an efficient dispersing agent that helps in achieving a uniform dispersion of the Ag/MWCNT-EDA and (2) it acts as a conductive bridge between particles (Ag and MWCNT-EDA), reducing the particle to particle resistivity. When inserted into polycarbonate, this three-phase blend successfully reduced the volume resistivity of the polymer by two orders of magnitude compared with previous approaches.

  1. Alumina/polymer-coated nanocrystals with extremely high stability used as a color conversion material in LEDs

    International Nuclear Information System (INIS)

    The long-term stability of quantum dot (QD)-based devices under harsh environmental conditions has been a critical bottleneck to be resolved for commercial use. Here, we demonstrate an extremely stable QD/alumina/polymer hybrid structure by combining internal atomic layer deposition (ALD) infilling with polymer encapsulation. ALD infilling and polymer encapsulation of QDs synergistically prohibit the degradation of QDs in terms of optical, thermal and humid attacks. Our hybrid QD/alumina/polymer film structure showed no noticeable reduction in photoluminescence even in a commercial grade test (85% humidity at 85?° C) over 28 days. In addition, we successfully fabricated a QD-based light-emitting device with excellent long-term stability by incorporating hybrid QD/alumina/polymer film as a color conversion material on light-emitting diode chips. (paper)

  2. Alumina/polymer-coated nanocrystals with extremely high stability used as a color conversion material in LEDs

    Science.gov (United States)

    Woo, Ju Yeon; Lee, Jongsoo; Han, Chang-Soo

    2013-12-01

    The long-term stability of quantum dot (QD)-based devices under harsh environmental conditions has been a critical bottleneck to be resolved for commercial use. Here, we demonstrate an extremely stable QD/alumina/polymer hybrid structure by combining internal atomic layer deposition (ALD) infilling with polymer encapsulation. ALD infilling and polymer encapsulation of QDs synergistically prohibit the degradation of QDs in terms of optical, thermal and humid attacks. Our hybrid QD/alumina/polymer film structure showed no noticeable reduction in photoluminescence even in a commercial grade test (85% humidity at 85?° C) over 28 days. In addition, we successfully fabricated a QD-based light-emitting device with excellent long-term stability by incorporating hybrid QD/alumina/polymer film as a color conversion material on light-emitting diode chips.

  3. Electrical conduction and dielectric relaxation in p-type PVA/CuI polymer composite

    OpenAIRE

    Makled, M.H.; Sheha, E.; Shanap, T.S.; El-Mansy, M.K.

    2012-01-01

    PVA/CuI polymer composite samples have been prepared and subjected to characterizations using FT-IR spectroscopy, DSC analysis, ac spectroscopy and dc conduction. The FT-IR spectral analysis shows remarkable variation of the absorption peak positions whereas DSC illustrates a little decrease of both glass transition temperature, Tg, and crystallization fraction, ?, with increasing CuI concentration. An increase of dc conductivity for PVA/CuI nano composite by increasing CuI concentration is r...

  4. Tunable architecture for flexible and highly conductive graphene-polymer composites

    OpenAIRE

    Noël, Amélie; Faucheu, Jenny; Rieu, Mathilde; Viricelle, Jean-Paul; Bourgeat-Lami, Elodie

    2014-01-01

    Printed electronics, particularly on flexible and textile substrates, raised a strong interest during the past decades. This work presents a good candidate for conductive inks based on a graphene/polymer nanocomposite material that gathers three main benefits that are 1 - neither clogging nor flocculation, 2 - spontaneous film formation around room temperature, 3 - high conductivity. Nanosized Multilayered Graphene (NMG) is produced through a solvent-free procedure, using a grinding process i...

  5. A silicon nanocrystal/polymer nanocomposite as a down-conversion layer in organic and hybrid solar cells

    Science.gov (United States)

    Svrcek, V.; Yamanari, T.; Mariotti, D.; Mitra, S.; Velusamy, T.; Matsubara, K.

    2015-07-01

    Silicon nanocrystal (Si-nc) down-conversion is demonstrated to enhance organic and hybrid organic/inorganic bulk heterojunction solar cells based on PTB7:[70]PCBM bulk heterojunction devices. Surfactant free surface-engineered Si-ncs can be integrated into the device architecture to be optically active and provide a means of effective down-conversion of blue photons (high energy photons below ~450 nm) into red photons (above ~680 nm) leading to 24% enhancement of the photocurrent under concentrated sunlight. We also demonstrate that the down-conversion effect under 1-sun is enhanced in the case of hybrid solar cells where engineered Si-ncs are also included in the active layer.Silicon nanocrystal (Si-nc) down-conversion is demonstrated to enhance organic and hybrid organic/inorganic bulk heterojunction solar cells based on PTB7:[70]PCBM bulk heterojunction devices. Surfactant free surface-engineered Si-ncs can be integrated into the device architecture to be optically active and provide a means of effective down-conversion of blue photons (high energy photons below ~450 nm) into red photons (above ~680 nm) leading to 24% enhancement of the photocurrent under concentrated sunlight. We also demonstrate that the down-conversion effect under 1-sun is enhanced in the case of hybrid solar cells where engineered Si-ncs are also included in the active layer. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02703a

  6. Conductivity and Dielectric Properties of Proton Conducting Poly (Vinyl) Chloride (PVC) Based Gel Polymer Electrolytes

    International Nuclear Information System (INIS)

    Poly (vinyl) chloride (PVC)-NH4I-EC films have been prepared by the solution cast technique. The sample containing 30 wt. % NH4I exhibited the highest room temperature conductivity of 4.60 x 10-7 S cm-1. The conductivity increased to 1.08 x 10-6 S cm-1 when 15 wt. % of ethylene carbonate (EC) was added to 70 wt. % PVC - 30 wt. % NH4I. The effects of ethylene carbonate (EC) addition on the frequency dependent dielectric properties of PVC based electrolytes were investigated by electrochemical impedance spectroscopy (EIS), in the temperature range of 300 K to 373 K. The dielectric properties and ac conductivity of the samples prepared have been analyzed. The values of dielectric constant were found to increase with increasing conductivity of the samples. Analysis of the ac conductivity data revealed the electrolytes to be of the non-Debye type with conduction mechanism of the overlapping-large-polaron-tunneling (OLPT) model. (author)

  7. Microfabrication of a Polymer Based Bi-Conductive Membrane for a Polymer Electrolyte Membrane Fuel Cell

    International Nuclear Information System (INIS)

    This paper reports a novel fabrication process of a high active area ratio bi-conductive membrane for PEMFCs. The fabricated device is a 50?m thick flexible polyimide based membrane that integrates for the first time lateral electrical conductive layers on both sides with a through ionic conductive path. With the use of thermo-conductive rubber as a bonding agent allowing a quick-flip process, five configurations of double-sided multilayer metal sputtering on polyimide were tested. An approach for filling through pores in the membrane with the ionic conductor (Nafion) with a temporary reservoir was also developed. The development of these new processes allowed to fabricate a membrane with 50?m wide holes filled with ionic conductor with double-sided electrical conductive layers

  8. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing.

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m(-1) range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering scaffolds. PMID:26351867

  9. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M.

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m-1 range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering scaffolds.

  10. Polymer Nanofibers with Outstanding Thermal Conductivity and Thermal Stability: Fundamental Linkage between Molecular Characteristics and Macroscopic Thermal Properties

    OpenAIRE

    ZHANG, Teng; Wu, Xufei; Luo, Tengfei

    2014-01-01

    Polymer nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of polymer nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of polymer nanof...

  11. Criteria for differentiating electron and ion conductivity in high-ohmic polymer solids

    International Nuclear Information System (INIS)

    The differentiation of electron and ion charge carriers is of principal importance for explaining the electrical properties of high polymer solids. Experimental methods allowing the differentiation between electron and ion charge carrier transport are summarized and estimated, particularly mass transport (mass spectroscopy, neutron activation analysis, and tracer technique) as direct methods as well as 'internal' electrical effects (d.c. characteristics and dielectric measurements) and 'external' electrical effects (electrochemical cell, electrode conditions, pressure dependence of conductivity, photoelectric effects) as indirect methods. The results obtained with various high-ohmic polymer solids are summarized and discussed. (author)

  12. Enhanced ionic conductivity and optical studies of plasticized (PEO-KCl) solid polymer electrolytes

    Science.gov (United States)

    Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    Solid polymer electrolytes (SPEs) based on Polyethylene oxide (PEO) doped with potassium chloride (KCl) were prepared by the solution cast technique. The conductivity increases from 10-10 to 10-6 Scm-1 at 303K with dopant. Optical absorption study shows that the direct & indirect optical band gaps were found decreased from 5.45-4.46eV and 4.96-3.86eV respectively with increasing the KCl. The XRD patterns reveal increasing the amorphous with increasing the dopent. The obtained results suggest that, these polymer systems are suitable candidates for solid state battery, electro chromic devices & optoelectronics display etc.

  13. Effect of the silica precursor on the conductivity of hectorite-derived polymer nanocomposites

    International Nuclear Information System (INIS)

    New hectorite and organo-hectorite clays have been prepared using different silica sol sources, in order to examine the importance of sol particle size, pH, and surface chemistry on the final matrix. Polymer-clay nanocomposites (PCN) are prepared by intercalating polyethylene oxide in the clay layers of lithium hectorites. The resulting films are physically and electrochemically evaluated. Conductivity values, activation energies, and lithium transference numbers indicate that the PCNs are single ion conductors with transference numbers close to unity. The activation energies are in the range of 0.02 V, two orders of magnitude lower than the conventional polymer electrolytes

  14. Electrical conductivity and dielectric properties of SiO2 nanoparticles dispersed in conducting polymer matrix

    International Nuclear Information System (INIS)

    Electrical and dielectric properties of conducting polypyrrole-wide band gap silica (PPY-SiO2) nanocomposites have been investigated as a function of temperature and frequency for different concentrations of polypyrrole. The average grain size of the nanocomposites is in the range of 40-80 nm. Impedance spectra reveal two distorted semicircles corresponding to grain and grain boundary effects. The magnitude of conductivity and its temperature variation are significantly different from polypyrrole and silica. A very large dielectric constant of about 4800 at 30 kHz and at room temperature has been observed for the highest concentration of silica. Inhomogeneous behavior of nanocomposites gives rise to high dielectric constant

  15. Control of conducting polymer actuators without physical feedback: simulated feedback control approach with particle swarm optimization

    Science.gov (United States)

    Xiang, Xingcan; Mutlu, Rahim; Alici, Gursel; Li, Weihua

    2014-03-01

    Conducting polymer actuators have shown significant potential in articulating micro instruments, manipulation devices, and robotics. However, implementing a feedback control strategy to enhance their positioning ability and accuracy in any application requires a feedback sensor, which is extremely large in size compared to the size of the actuators. Therefore, this paper proposes a new sensorless control scheme without the use of a position feedback sensor. With the help of the system identification technique and particle swarm optimization, the control scheme, which we call the simulated feedback control system, showed a satisfactory command tracking performance for the conducting polymer actuator’s step and dynamic displacement responses, especially under a disturbance, without needing a physical feedback loop, but using a simulated feedback loop. The primary contribution of this study is to propose and experimentally evaluate the simulated feedback control scheme for a class of the conducting polymer actuators known as tri-layer polymer actuators, which can operate both in dry and wet media. This control approach can also be extended to other smart actuators or systems, for which the feedback control based on external sensing is impractical.

  16. Application of the Kelvin Probe method for screening the interfacial reactivity of conducting polymer based coatings for corrosion protection

    International Nuclear Information System (INIS)

    In our recent studies we could show that intrinsically conducting polymers definitely possess promising potential for application in intelligent corrosion protection coatings. One prerequisite for this was shown to be that macroscopic networks of the conducting polymers have to be avoided in the coating in order to avoid predominant and disastrously fast cation incorporation during the corrosion induced reduction of the polymer. Only then anions serving as inhibitors and safely stored in the conducting polymer will be efficiently released during a corrosive attack. This mechanism is more or less independent of the metal that has to be protected, i.e. it is a property of the composite coating derived from dispersing micro-clusters of conducting polymer in a non-conducting matrix and unspecific for the metal onto which it is to be applied. In this paper we focus on specific electrochemical reactions at the interface between the conducting polymer and the metal that were found to define further criteria for successful application. The aim should be that the conducting polymer is in electronic contact with the passive metal surface. However, the formation of an insulating interface, i.e. loss of electronic contact and hence functional inactivity of the conducting polymer, and enhanced corrosion are also possible. We will show how by application of the Kelvin Probe method a fast and easy screening between these three cases can be achieved.

  17. Fabrication and Optical Properties of Electrospun Conductive Polymer Nanofibers from Blended Polymer Solution

    Science.gov (United States)

    Chuangchote, Surawut; Sagawa, Takashi; Yoshikawa, Susumu

    2008-01-01

    Ultrafine poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV)/poly(vinyl pyrrolidone) (PVP) composite fibers with the average diameters ranging from 43 nm to 1.7 µm were prepared by electrospinning of blended polymer solutions in mixed solvent of chlorobenzene and methanol. The average diameter of the as-spun fibers was found to decrease into nanometer scale with decreasing the PVP concentration and/or addition of a volatile organic salt, pyridinium formate (PF). PVP was easily removed from MEH-PPV/PVP fibers by the Soxhlet extraction, and after the removal, pure MEH-PPV fibers were obtained as a ribbon-like structure aligned with wrinkled surface in fiber direction. Comparison with the cast film, as-spun fibers showed relatively higher crystallinity, higher conjugation length, and there was a remarkable blue shift of photoluminescence (PL) peak.

  18. New fabrication technique of conductive polymer/insulating polymer composite films and evaluation of biocompatibility in neuron cultures

    International Nuclear Information System (INIS)

    Poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical and electrochemical properties very similar to those of polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion rate of the electrolyte across the PVA film to the indium tin oxide (ITO) electrode. In particular, a solvent with a hydrophilic nature easily penetrates into the PVA film. By applying this new process, we demonstrate a unique method of forming an electrically conductive pattern in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using the conducting polymer, PPy. Then, by applying a similar technique, we fabricated poly(3,4-ethylenedioxythiophene), PEDOT/PVA, composite films and investigated their basic electrochemical properties. Moreover, in this study, in order to develop a novel cell-culture system which makes it possible to communicate with cultured cells, fibroblasts were cultured on PPy- and PEDOT-coated ITO conductive glass plates for 7 days. The result reveals that the PPy and PEDOT films support the secretory functions of the cells cultured on its surface. The PPy- and PEDOT-coated electrodes may be useful to culture the cells on.

  19. Ion-beam modifications of the surface morphology and conductivity in some polymer thin films

    Indian Academy of Sciences (India)

    M Ramakrishna Murthy; E Venkateshwar Rao

    2002-10-01

    Studies on the surface micromorphology and surface conductivity in thin polymer films of poly vinyl alcohol (PVA) and poly ethylene oxide (PEO) in both as-grown and ion-implanted polymer films have been carried out to reveal certain specific features of the ordered state in these materials. Optical microscopic investigations revealed the existence and enhanced formation in number of spherulites and dendrites in ionimplanted films relative to the as-grown films. The number and rate of formation of spherulites indicated an increase in the degree of crystallinity in these films. Measurements of surface conductivity of as-grown and ion-implanted polymer films, employing four-point probe method, indicated a decrease in electrical conductivity on ion-implantation. Photomicrographic analysis of the PVA and PEO thin film surfaces, has enabled to propose a temperature–stress induced mechanism of crystallization in conjunction with the surface conductivity measurements. The decrease in surface conductivity on ion-implantation in both PVA and PEO thin films, is attributed to a decrease in mobility of macromolecular charged species due to an increase in degree of crystallinity as has been observed by optical microscopy.

  20. Conductivity and Structural Studies of Plasticised Polyacrylonitrile (PAN)-Lithium Triflate Polymer Electrolyte Films

    International Nuclear Information System (INIS)

    The effect of different plasticizers on the properties of PAN-LiCF3SO3 polymer electrolytes has been studied. Propylene carbonate (PC) and ethylene carbonate (EC) having different values of donor numbers, dielectric constant and viscosity have been used as plasticizers. The highest room temperature conductivity for the film in the PAN-LiCF3SO3 system was 3.04 x 10-4 S cm-1. The highest room temperature conductivity for the films in the PAN-EC-LiCF3SO3 system and the PAN-PC-LiCF3SO3 system was 1.32 x 10-3 and 8.64 x 10-4 S cm-1. The addition of plasticizers has been found to enhance the conductivity of polymer electrolytes by increasing the amorphous content as well as by dissociating the ion aggregates present in polymer electrolyte. Conductivity temperature-dependence studies of these plasticised PAN-salt systems were carried out in the temperature range of 303 to 373 K. The conductivity versus temperature plots obeyed an Arrhenius type variation. The structural and complex formations were studied by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. (author)

  1. Characteristics of organic light-emitting diodes with conducting polymer anodes on plastic substrates

    Science.gov (United States)

    Huh, Jin Woo; Kim, Young Min; Park, Young Wook; Choi, Jin Hwan; Lee, Jin Woo; Lee, Jong Woo; Yang, Jae Woong; Ju, Sung Hoo; Paek, Kyeong Kap; Ju, Byeong Kwon

    2008-02-01

    The fabrication of conducting polymer films by a screen-printing method and characterization of an organic light-emitting diode (OLED) implemented using these films as an anode on plastic substrates are reported. Organic transparent electrode materials containing poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonic acid) (PSS) (PEDOT:PSS) were used after the modification by a unique nanoparticle binder design. The electro-optical properties as well as mechanical stabilities of these films were measured. The OLED performances when employing these films were comparable to that of OLEDs using indium tin oxide (ITO) despite their relatively poor conductivity. An external quantum efficiency of the OLED using this anode is ˜3.5%, which is about twice as that of OLEDs using ITO. These results show that the organic transparent electrode of a conducting polymer film patterned by the screen-printing method is a potential candidate for an electrode of the flexible OLED.

  2. Study on power generation using electro-conductive polymer and its mixture with magnetic fluid

    International Nuclear Information System (INIS)

    A new power generation system using electro-conductive polymer and its mixture with magnetic fluid is introduced. The system using non-poison electro-conductive polymer and its mixture with magnetic fluid and operating at room temperature is proposed in the present paper. The system could be used as a micro-distributed energy supply system for domestic use in the future. An experimental set-up is designed and established to investigate the performance of the power generation with an aid of a theoretical analysis of the power generation. It is found that the theoretical results are in good agreement with the measured data. Based on the obtained results, the electric output increases with Reynolds number, size of the test channel, magnetic strength and electric conductivity. It is understood that in order to obtain a practical power generation, priority should be put on increasing fluid flow velocity and magnetic field strength

  3. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

    OpenAIRE

    Chawla, Parul; Singh, Son; Sharma, Shailesh Narain

    2014-01-01

    In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe) chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO) and tri-n-octylphosphine (TOP) and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene) polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-order...

  4. Conductive polymer-mediated 2D and 3D arrays of Mn3O4 nanoblocks and mesoporous conductive polymers as their replicas

    Science.gov (United States)

    Nakagawa, Yoshitaka; Kageyama, Hiroyuki; Matsumoto, Riho; Oaki, Yuya; Imai, Hiroaki

    2015-11-01

    Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery.Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05912g

  5. Electrically Conductive, Optically Transparent Polymer/Carbon Nanotube Composites and Process for Preparation Thereof

    Science.gov (United States)

    Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor); Park, Cheol (Inventor); Watson, Kent A. (Inventor); Ounaies, Zoubeida (Inventor)

    2011-01-01

    The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

  6. Importance of energetics in the design of small bandgap conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yongsok; Kertesz, M. (Georgetown Univ., Washington, DC (USA)); Elsenbaumer, R.L. (Allied-Signal Co., Morristown, NJ (USA))

    With a combination of semiempirical quantum chemical methods applicable for geometry optimization and energy band structure calculation, several heteroatomic conjugated polymers based on polythiophene have been studied with the goal to correlate the chemical composition and topology of the unit cells with energetics and bandgaps. In the theoretical design of small E{sub g} polymers the relative stability of structural isomers of a given polymer plays a crucial role. The authors have found for the materials investigated in this work that the structure having the larger bandgap among structural isomorphs is the more stable one. The combination of MNDO and Hueckel crystal orbital methods provide a firm theoretical basis to the synthesis of small-bandgap conducting polymeric materials.

  7. Protection of Conductive and Non-conductive Advanced Polymer-based Paints from Highly Aggressive Oxidative Environments

    Science.gov (United States)

    Gudimenko, Y.; Ng, R.; Iskanderova, Z.; Kleiman, J.; Grigorevsky, A.; Kiseleva, L.; Finckenor, M.; Edwards, D.

    2005-01-01

    Research has been continued to further improve the space durability of conductive and non-conductive polymer-based paints and of conductive thermal control paints for space applications. Efforts have been made to enhance the space durability and stability of functional Characteristics in ground-based space environment imitating conditions, using specially developed surface modification treatment. The results of surface modification of new conductive paints, including the ground-based testing in aggressive oxidative environments, such as atomic oxygen/UV and oxygen plasma, and performance evaluation are presented. Functional properties and performance characteristics, such as thermal optical properties (differential solar absorptance and thermal emittance representing the thermal optical performance of thermal control paints) and surface resistivity characteristics of pristine, surface modified, and tested materials were verified. Extensive surface analysis studies have been performed using complementary surface analyses including SEM/EDS and XPS. Test results revealed that the successfully treated materials exhibit reduced mass loss and no surface morphology change, thus indicating good protection from the severe oxidative environment. It was demonstrated that the developed surface modification treatment could be applied successfully to charge dissipative and conductive paints.

  8. Modification of Conductive Polymer for Polymeric Anodes of Flexible Organic Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Wang Guang-Feng

    2009-01-01

    Full Text Available Abstract A conductive polymer, poly(3,4-ethylenedioxythiophene:poly(styrene sulfonate (PEDOT:PSS, was modified with dimethyl sulfoxide (DMSO in solution state, together with sub-sequential thermal treatment of its spin-coated film. The electrical conductivity increased by more than three orders of magnitude improvement was achieved. The mechanism for the conductivity improvement was studied at nanoscale by particle size analysis, field emission scanning electron microscopy (FESEM, and X-ray photoelectron spectroscopy (XPS. Smaller particle size was observed, resulting in larger contact area and better electrical conductive connections. Connection of conductive PEDOT increased on the surface of the PEDOT:PSS particles, which promoted high conductivity. Flexible anodes based on the modified PEDOT:PSS were fabricated. Flexible organic light-emitting diodes (FOLED based the polymeric anodes have a comparable performance to those on indium–tin–oxide (ITO anodes.

  9. Polymer Nanofibers with Outstanding Thermal Conductivity and Thermal Stability: Fundamental Linkage between Molecular Characteristics and Macroscopic Thermal Properties

    CERN Document Server

    Zhang, Teng; Luo, Tengfei

    2014-01-01

    Polymer nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of polymer nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of polymer nanofibers. Ten different polymer nanofibers with systematically chosen molecular structures are studied using large scale molecular dynamics simulations. We found that high thermal conductivity and good thermal stability can be achieved in polymers with rigid backbones, exemplified by {\\pi}-conjugated polymers, due to suppressed segmental rotations and large phonon group velocities. The low probability of segmental rotation does not only prevent temperature-induced phase transition but also enables long phonon mean free paths due to reduced di...

  10. Investigation of uniaxial stretching effects on the electrical conductivity of CNT–polymer nanocomposites

    International Nuclear Information System (INIS)

    A theoretical study is carried out to investigate the effects of uniaxial stretching on the electrical conductivity of carbon nanotube (CNT)–polymer composites using a mixed micromechanics model, which incorporates two conductivity mechanisms: electron hopping and conductive networks. The uniaxial stretching induces volume expansion of the composites, re-orientation of CNTs and a change in conductive networks, which are characterized by the variation of the CNT concentration, the CNT orientation distribution function and the percolation threshold, respectively. Modelling results demonstrate that stretching decreases the electrical conductivity of the composite in both the longitudinal and transverse directions. It is also observed that stretching has more significant effects on the electrical conductivity of the composites with a lower CNT volume fraction. Furthermore, the effects of Poisson's ratio on the electrical conductivity are also investigated. Possible reasons for the observed phenomena are interpreted. This work can be claimed to provide a theoretical prediction on the trend of the stretching effects on the electrical properties of CNT–polymer composites. (paper)

  11. Nanoscale direct mapping of localized and induced noise sources on conducting polymer films.

    Science.gov (United States)

    Shekhar, Shashank; Cho, Duckhyung; Lee, Hyungwoo; Cho, Dong-Guk; Hong, Seunghun

    2015-12-23

    The localized noise-sources and those induced by external-stimuli were directly mapped by using a conducting-AFM integrated with a custom-designed noise measurement set-up. In this method, current and noise images of a poly(9,9-dioctylfluorene)-polymer-film on a conducting-substrate were recorded simultaneously, enabling the mapping of the resistivity and noise source density (NT). The polymer-films exhibited separate regions with high or low resistivities, which were attributed to the ordered or disordered phases, respectively. A larger number of noise-sources were observed in the disordered-phase-regions than in the ordered-phase regions, due to structural disordering. Increased bias-voltages on the disordered-phase-regions resulted in increased NT, which is explained by the structural deformation at high bias-voltages. On photo-illumination, the ordered-phase-regions exhibited a rather large increase in the conductivity and NT. Presumably, the illumination released carriers from deep-traps which should work as additional noise-sources. These results show that our methods provide valuable insights into noise-sources and, thus, can be powerful tools for basic research and practical applications of conducting polymer films. PMID:26530520

  12. Micropatterning of a stretchable conductive polymer using inkjet printing and agarose stamping

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Hassager, Ole

    2007-01-01

    A highly conducting stretchable polymer material has been patterned using additive inkjet printing and by subtractive agarose stamping of a deactivation agent (hypochlorite). The material consisted of elastomeric polyurethane combined in an interpenetrating network with a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT). The agarose stamping produced 50 ?m wide conducting lines with high spatial fidelity. The deactivation agent was found to cause some degradation of the remaining conducting lines, as revealed by a stronger increase in resistance upon straining compared to the pristine polymer material. Inkjet printing of the material was only possible if a short-chain polyurethane was used as elastomer to overcome strain hardening at the neck of the droplets produced for printing. Reproducible line widths down to 200 ?m could be achieved by inkjet printing. Both methods were used to fabricate test patterns that allowed the electrical resistance parallel and perpendicular to the elongation direction to be measured. Electrical resistance increased both parallel and perpendicular to the direction of strain, with a faster increase observed parallel to the straining.

  13. Organic-Inorganic Nanocomposites via Placing Monodisperse Ferroelectric Nanocrystals in Direct and Permanent Contact with Ferroelectric Polymers.

    Science.gov (United States)

    Jiang, Beibei; Pang, Xinchang; Li, Bo; Lin, Zhiqun

    2015-09-16

    Organic-inorganic nanocomposites composed of polymers and nanoparticles offer a vast design space of potential material properties, depending heavily on the properties of these two constituents and their spatial arrangement. The ability to place polymers in direct contact with functional nanoparticles via strong bonding, that is, stable chemical interaction without the dissociation of surface capping polymers, provides a means of preventing nanoparticles from aggregation and increasing their dispersibility in nanocomposites, and promises opportunities to explore new properties and construction of miniaturized devices. However, this is still a challenging issue and has not yet been largely explored. Here, we report an unconventional strategy to create in situ organic-inorganic nanocomposites comprising monodisperse ferroelectric nanoparticles directly and permanently tethered with ferroelectric polymers by capitalizing on rationally designed amphiphilic star-like diblock copolymer as nanoreactors. The diameter of ferroelectric nanoparticles and the chain length of ferroelectric polymers can be precisely tuned. The dielectric and ferroelectric properties of nanocomposites containing different sizes of ferroelectric nanoparticles were scrutinized. Such bottom-up crafting of intimate organic-inorganic nanocomposites offers new levels of tailorability to nanostructured materials and promises new opportunities for achieving exquisite control over the surface chemistry and properties of nanocomposites with engineered functionality for diverse applications in energy conversion and storage, catalysis, electronics, nanotechnology, and biotechnology. PMID:26314224

  14. Conductivity of microfibrillar polymer-polymer composites with CNT-loaded microfibrils or compatibilizer: A comparative study

    Directory of Open Access Journals (Sweden)

    S. Fakirov

    2013-07-01

    Full Text Available Conductive polymer composites have wide ranging applications, but when they are produced by conventional melt blending, high conductive filler loadings are normally required, hindering their processability and reducing mechanical properties. In this study, two types of polymer-polymer composites were studied: i microfibrillar composites (MFC of polypropylene (PP and 5 wt% carbon nanotube (CNT loaded poly(butylene terephthalate (PBT as reinforcement, and ii maleic anhydride-grafted polypropylene (PP-g-MA compatibilizer, loaded with 5 wt% CNTs introduced into an MFC of PP and poly(ethylene terephthalate (PET in concentrations of 5 and 10 wt%. For the compatibilized composite type, PP and PET were melt-blended, cold-drawn and pelletized, followed by dry-mixing with PP-g-MA/CNT, re-extrusion at 200°C, and cold-drawing. The drawn blends produced were compression moulded to produce sheets with MFC structure. Using scanning electron microscopy, CNTs coated with PP-g-MA could be observed at the interface between PP matrix and PET microfibrils in the compatibilized blends. The volume resistivities tested by four-point test method were: 2.87•108 and 9.93•107 ?•cm for the 66.5/28.5/5 and 63/27/10 (by wt% PP/PET/(PP-g-MA/CNT blends, corresponding to total CNT loadings (in the composites of 0.07 vol% (0.24 wt% and 0.14 vol% (0.46 wt%, respectively. For the non-compatibilized MFC types based on PP/(PBT/CNT with higher and lower melt flow grades of PP, the resistivities of 70/(95/5 blends were 1.9•106 and 1.5•107 ?•cm, respectively, corresponding to a total filler loading (in the composite of 0.44 vol% (1.5 wt% in both MFCs.

  15. Smart Surface Chemistries of Conducting Polymers : for Guiding Cell Behavior in Polymeric Microsystems

    DEFF Research Database (Denmark)

    Lind, Johan Ulrik

    2012-01-01

    In this thesis we investigate post-polymerization covalent modifications of poly(3,4-dioxythiophene (PEDOT)-type conducting polymers. The aim of the modifications is to gain specific control of the interaction between the material and living mammalian cells. The use of “click-chemistry” to modify an azide-modified PEDOT, poly(3,4-(1-azidomethylethylene)-dioxythiophene) (PEDOT-N3), is studied in detail, and found to be a valuable approach. This is concluded, as we are able to obtain delicate control of cellular adhesion, by covalently attaching appropriate bio-functional molecules onto PEDOT-N3 thin film substrates. Complementing these findings, we introduce a novel technique for fabricating surface chemical gradients on PEDOT-N3 substrates. The technique is based on applying “electro-click chemistry” to locally induce covalent modifications. Further supplementing these results, we develop a straightforward and in-expensive method for patterning conducting polymer thin films into microelectrodes, without losing control of the surface chemistry of the samples. On the contrary, the method provides direct control of the surface chemistry of both the fabricated micro-electrodes and the gaps between them. The method is based on locally removing PEDOTtype polymers to expose underlying non-conducting functional polymer substrates. Thereby, multifunctional substrates are obtained. By applying this method, we are able to fabricate allpolymer micro-systems with multiple types of localized functional (bio)-chemistries. In the course of our studies, we find that PEDOT-N3 thin films undergo a significant yet reversible swelling when exposed to dimethyl-sulfoxide (DMSO). This swelling is found to be of practical use for controlling the reaction density and depth. This, for example, enables the fabrication of dense poly-ethylene-glycol-coatings of the conducting polymer substrates. These coatings render the substrates resistant to protein adsorption. Hence, the choice of solvent is found to be a key parameter for achieving functional post-polymerization modifications of PEDOT-N3. The methods developed in this thesis are highly generic, and can therefore be applied for fabricating a diversity of microsystems based on conducting polymers, with multiple types of localized and highly bio-specific surfaces chemistries.

  16. Preparation of Composite Polymer Electrolytes by Electrons-Induced Grafting: Proton and Lithium Conducting Membranes

    International Nuclear Information System (INIS)

    Polymer electrolyte membranes (PEMs) are a class of materials that is receiving an increasing attention due to their applicability to a wide number of solid state devices and chemical processes. Proton (H+) and lithium ion (Li+) conducting membranes are of particular interest as both on increasing demand to prompt the commercialization of polymer electrolyte fuel cell and polymer electrolyte lithium battery. Radiation-induced grafting is a potential alternative method to prepare PEMs. During PEMs preparation, grafting reaction is often carried out using pre-irradiation method or simultaneous irradiation method (with ?-rays). However, reports on the use of simultaneous method with electron beam (EB) to prepare such membranes are very scarce. The objective of this work is to prepare and characterize two distinct polymer electrolyte membranes for possible use in fuel cell and lithium battery using single simultaneous radiation-induced grafting method with EB. Initially, styrene was impregnated into the porous structure of poly(vinylidene fluoride) (PVDF) films followed by simultaneous irradiation with EB using doses up to 50 kGy under N2 and at room temperature. Subsequently, the obtained polystyrene pore filled PVDF films (membrane precursor) were functionalized using two different chemical treatments. The first treatment includes sulfonation with chlorosulfonic acid/1,1,2,2-tetrachloroethane mixture to obtain H+ conducting composite membranes. The second treatment involves activation of the polystyrene pore filled PVDF films with LiPF6/EC/DC liquid electrolyte under to obtain Li+ conducting composite membranes. The micro-structure of both composite membranes was investigated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The content of polystyrene grafted in the pores, water uptake, electrolyte uptake and ionic conductivity were measured. The obtained composite electrolyte membranes were found to achieve grafting yield up to 46% with superior Li+ conductivity values up to 1.9 10-3 S/cm when treated with LiPH6/EC/DC electrolyte solution and H+ conductivity of 5.95 x 10-2 S/cm when sulfonated with 10% chlorosulfonic acid. The results of this work suggests that simultaneous radiation-induced grafting with EB offers a single versatile root to prepare two high quality composite polymer electrolyte membranes conducting H+ and Li+ for possible use in fuel cell and lithium batteries, respectively

  17. Improvement of Conductive Micropattern in a LIFT Process with a Polymer Coating Layer

    Science.gov (United States)

    Lee, Bong-Gu

    2009-03-01

    The Laser-Induced Forward Transfer (LIFT) process is a modified, conventional LIFT technology where a polymer coating layer of a transparent substrate is used to transform the laser energy into kinetic energy in order to transfer the deposited target material. Micropatterning is achieved by scanning the laser beam and translating the acceptor substrate. In this study, a modified process based on LIFT is proposed. This process has been applied to micropatterning and electric circuit printing technology. The proposed technology introduces a polymer coating layer on the transparent substrate for the LIFT process. The proposed LIFT technology facilitates fabrication of conductive micropatterns with accurate geometry by creating electric circuits with improved conducting performance. Modification of the LIFT process is discussed, and the properties of the fabricated material are measured and compared to those of a material obtained with the conventional LIFT method.

  18. Li Ion Conducting Polymer Gel Electrolytes Based on Ionic Liquid/PVDF-HFP Blends

    Science.gov (United States)

    Ye, Hui; Huang, Jian; Xu, Jun John; Khalfan, Amish; Greenbaum, Steve G.

    2009-01-01

    Ionic liquids thermodynamically compatible with Li metal are very promising for applications to rechargeable lithium batteries. 1-methyl-3-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P13TFSI) is screened out as a particularly promising ionic liquid in this study. Dimensionally stable, elastic, flexible, nonvolatile polymer gel electrolytes (PGEs) with high electrochemical stabilities, high ionic conductivities and other desirable properties have been synthesized by dissolving Li imide salt (LiTFSI) in P13TFSI ionic liquid and then mixing the electrolyte solution with poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP) copolymer. Adding small amounts of ethylene carbonate to the polymer gel electrolytes dramatically improves the ionic conductivity, net Li ion transport concentration, and Li ion transport kinetics of these electrolytes. They are thus favorable and offer good prospects in the application to rechargeable Li batteries including open systems like Li/air batteries, as well as more “conventional” rechargeable lithium and lithium ion batteries. PMID:20354587

  19. Electrochemical and Optical Investigation of Conductive Polymer and MWCNT Nanocomposite Film

    Scientific Electronic Library Online (English)

    Ali, Ehsani; Ferydon, Babaei; Hossein, Mostaanzadeh.

    2015-02-01

    Full Text Available Composites of multi-walled carbon nanotubes (MWCNT) and conductive polymer with good uniformity were prepared by electropolymerization. Molecular modeling calculations were carried out for electroactive monomer (OAP) polymerization with density functional theory (DFT) level using 6-311G(d,p) basis s [...] et for all atoms and Gaussian 03 program package. The reflectance and transmittance amplitudes of the composite were obtained, using the continuity of the tangential components of electrical and magnetic fields at interfaces and solving the algebraic matrix equation. The calculated absorbance spectra as a function of wavelength for MWCNTs dispersed in the conductive polymer are depicted. Band gap of the p-type semiconducting film was obtained from the plot of (?hv)2 vs. photon energy.

  20. Elucidation of charge storage characteristics of conducting polymer film using redox reaction

    CERN Document Server

    Contractor, Asfiya Q

    2013-01-01

    A general technique to investigate charge storage characteristics of conducting polymer films has been developed. A redox reaction is conducted on a polymer film on a rotating disk electrode under potentiostatic condition so that the rate of charging of the film equals the rate of removal of the charge by the reaction. In an experiment on polyaniline film deposited on platinum substrate, using Fe2+/Fe3+ in HCl as the redox system, the voltammogram shows five distinct linear segments (bands) with discontinuity in the slope at specific transition potentials. These bands are the same as those indicated by ESR/Raman spectroscopy with comparable transition potentials. From the dependence of the slopes of the bands on concentration of ferrous and ferric ions, it was possible to estimate the energies of the charge carrier in different bands. It is shown that the charge storage in the film is capacitive.

  1. Conducting polymers doped with a mineral phase: structural and electrical study

    Science.gov (United States)

    González, C. P.; Montaño, A. M.; Estrada, S.; Ortiz, C.

    2013-11-01

    This work reports the results obtained of a series of novel doped conducting polymers (CPs) of polyaniline/hematite (PANI/HEM), which were synthesized in acidic aqueous solution by the in situ chemical oxidative polymerization, using ammonium peroxydisulfate as oxidant reagent. The synthesis was carried out with 20, 40 y 60 % (weight percent) contents of hematite (HEM) at 8 and 14 h of polymerization times (tP). These composites were structurally characterized by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). An electrochemical analysis was made by Electrochemical impedance spectroscopy (EIS). Results of this study allow to evaluate the influence of hematite on the improvement of the structural properties and in the increase of the electric conductivity (sac) of the doped polymers compared to CPs without dopant agents.

  2. Li Ion Conducting Polymer Gel Electrolytes Based on Ionic Liquid/PVDF-HFP Blends

    OpenAIRE

    Ye, Hui; HUANG, JIAN; Xu, Jun John; Khalfan, Amish; Greenbaum, Steve G.

    2007-01-01

    Ionic liquids thermodynamically compatible with Li metal are very promising for applications to rechargeable lithium batteries. 1-methyl-3-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P13TFSI) is screened out as a particularly promising ionic liquid in this study. Dimensionally stable, elastic, flexible, nonvolatile polymer gel electrolytes (PGEs) with high electrochemical stabilities, high ionic conductivities and other desirable properties have been synthesized by dissolving Li i...

  3. Experimental and theoretical characterization of implantable neural microelectrodes modified with conducting polymer nanotubes

    OpenAIRE

    Abidian, Mohammad Reza; Martin, David C.

    2008-01-01

    Neural prostheses transduce bioelectric signals to electronic signals at the interface between neural tissue and neural microelectrodes. A low impedance electrode-tissue interface is important for the quality of signal during recording as well as quantity of applied charge density during stimulation. However, neural microelectrode sites exhibit high impedance because of their small geometric surface area. Here we analyze nanostructured-conducting polymers that can be used to significantly dec...

  4. Conductive Polymer Microelectrodes for on-chip measurement of transmitter release from living cells

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Matteucci, Marco; Taboryski, Rafael J.

    2012-01-01

    In this paper, we present techniques to trap a group of neuronal cells (PC 12) close to band microelectrodes and quantitatively measure cellular transmitter release. Different trapping approaches were investigated including coating of electrodes by layers enhancing cell attachment and by pressure driven cell trapping inside closed chip devices. Conductive polymer microelectrodes were used to measure transmitter release using electrochemical methods such as cyclic voltammetry and constant potenti...

  5. How the type of input function affects the dynamic response of conducting polymer actuators

    Science.gov (United States)

    Xiang, Xingcan; Alici, Gursel; Mutlu, Rahim; Li, Weihua

    2014-10-01

    There has been a growing interest in smart actuators typified by conducting polymer actuators, especially in their (i) fabrication, modeling and control with minimum external data and (ii) applications in bio-inspired devices, robotics and mechatronics. Their control is a challenging research problem due to the complex and nonlinear properties of these actuators, which cannot be predicted accurately. Based on an input-shaping technique, we propose a new method to improve the conducting polymer actuators’ command-following ability, while minimizing their electric power consumption. We applied four input functions with smooth characteristics to a trilayer conducting polymer actuator to experimentally evaluate its command-following ability under an open-loop control strategy and a simulated feedback control strategy, and, more importantly, to quantify how the type of input function affects the dynamic response of this class of actuators. We have found that the four smooth inputs consume less electrical power than sharp inputs such as a step input with discontinuous higher-order derivatives. We also obtained an improved transient response performance from the smooth inputs, especially under the simulated feedback control strategy, which we have proposed previously [X Xiang, R Mutlu, G Alici, and W Li, 2014 “Control of conducting polymer actuators without physical feedback: simulated feedback control approach with particle swarm optimization’, Journal of Smart Materials and Structure, 23]. The idea of using a smooth input command, which results in lower power consumption and better control performance, can be extended to other smart actuators. Consuming less electrical energy or power will have a direct effect on enhancing the operational life of these actuators.

  6. Percolation-dominated conductivity in a conjugated-polymer-carbon-nanotube composite

    OpenAIRE

    COLEMAN, JONATHAN NESBIT; BARKLIE, ROBERT CHARLES; BLAU, WERNER

    1998-01-01

    We have made electrical measurements on a system using carbon nanotubes as the dopant material. A semiconjugated, organic polymer was mixed with carbon nanotubes to form a wholly organic composite. Composite formation from low to high nanotube concentration increases the conductivity dramatically by ten orders of magnitude, indicative of percolative behavior. Effective mobilities were calculated from the space-charge regions of the current-voltage characteristics for the 0–8 % mass fractions....

  7. Performance Improvement by Layout Designs of Conductive Polymer Microelectrode Based Impedimetric Biosensors

    DEFF Research Database (Denmark)

    Rosati, Giulio; Daprà, Johannes; Cherré, Solène; Rozlosnik, Noemi

    2014-01-01

    In this work we present a theoretical, computational, and experimental evaluation of the performance of an impedimetric biosensor based on interdigitated conductive polymer (PEDOT:TsO) microelectrodes in a microfluidic system. The influence of the geometry of the electrodes and microchannels on the electrochemical performance of the biosensor was exploited to improve the detection system. The developed model allowed us to predict the performance of the electrochemical system, and thus to optimiz...

  8. Micropatterning of Functional Conductive Polymers with Multiple Surface Chemistries in Register

    DEFF Research Database (Denmark)

    Lind, Johan Ulrik; Acikgo?z, Canet; Daugaard, Anders Egede; Andresen, Thomas Lars; Hvilsted, Søren; Textor, Marcus; Larsen, Niels Bent

    2012-01-01

    A versatile procedure is presented for fast and efficient micropatterning of multiple types of covalently bound surface chemistry in perfect register on and between conductive polymer microcircuits. The micropatterning principle is applied to several types of native and functionalized PEDOT (poly(3,4-ethylenedioxythiophene)) thin films. The method is based on contacting PEDOT-type thin films with a micropatterned agarose stamp containing an oxidant (aqueous hypochlorite) and applying a nonionic ...

  9. Influence of conductive polymer doping on the viability of cardiac progenitor cells

    OpenAIRE

    Gelmi, Amy; Kozak Ljunggren, Monika; Rafat, Mehrdad; Jager, Edwin

    2014-01-01

    Cardiac tissue engineering via the use of stem cells is the future for repairing impaired heart function that results from a myocardial infarction. Developing an optimised platform to support the stem cells is vital to realising this, and through utilising new smart materials such as conductive polymers we can provide a multi-pronged approach to supporting and stimulating the stem cells via engineered surface properties, electrical, and electromechanical stimulation. Here we present a fundame...

  10. Electroactive Surfaces Based on Conducting Polymers for Controlling Cell Adhesion, Signaling, and Proliferation

    OpenAIRE

    Jager, Edwin; Bolin, Maria; Svennersten, Karl; WANG X.; Richter-Dahlfors, Agneta; BERGGREN, Magnus

    2009-01-01

    We report on a variety of electroactive surfaces for the control of in vitro cell adhesion, proliferation, and stimulation. Planar cell culture substrates have been coated with the conducting polymer PEDOT and by switching the redox state, adhesion and proliferation of MDCK epithelial cells was controlled as well as stem cell seeding density. Electronically active 3D-scaffolds based on electrospun PET nano-fibers coated with PEDOT have been used as a substrate to culture SH-SY5Y neuroblastoma...

  11. Impedance Study of Drinking Water and Tastants Using Conducting Polymer and Metal Electrodes

    Directory of Open Access Journals (Sweden)

    Pawan Kapur

    2012-05-01

    Full Text Available In this study the sensing capabilities of a combination of metals and conducting polymer electrodes for drinking water and dissolved tastants using an AC-impedance mode in frequency range 102 to 105 Hz at 0.1 V potential has been carried out. Classification of seven different bottled and municipal drinking water samples along with various tastants dissolved in DI water(DI water for KCl (5mM (salty, HCl (5 mM (sour quinine (0.1 mM (bitter, sucrose (5 mM (sweet, black tea liquor, black tea liquor with sucrose (2% sugar solution, and a bottle of “packed” orange juice has been made using six different working electrodes in a multi electrode setup using PCA. Working electrodes of Platinum (Pt, Gold (Au, Silver (Ag, Glassy Carbon (GC and conducting polymer electrodes of Polyaniline (PANI and Polypyrrole (PPY grown on an ITO surface potentiostatically have been deployed in a three electrode set up. The impedance response of these water samples using number of working electrodes shows a decrease in the real and imaginary impedance values presented on nyquist plots depending upon the nature of the electrode and amount of dissolved salts present in water/tastants. The different sensing surfaces allowed a high cross-selectivity in response to the same analyte. From PCA plots it was possible to classify drinking water in 3-4 classes using conducting polymer electrodes; however tastants were well separated from the PCA plots employing the impedance data of both conducting polymer and metal electrodes.

  12. Novel in situ electrochemical deposition of platinum nanoparticles by sinusoïdal voltages on conducting polymer films.

    OpenAIRE

    Lupu, Stelian; Lakard, Boris; Hihn, Jean-Yves; Dejeu, Jérôme

    2012-01-01

    Platinum (Pt) nanoparticles were successfully electrodeposited in situ on an organic conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), using for the first time sinusoidal voltages of various frequencies in a chloroplatinic acid solution. The organic PEDOT matrix was electrodeposited on Pt electrode chips. The Pt electrode chips consist of a 150 nm Pt layer deposited on 100-oriented standard 3'' silicon wafers. The cyclic voltammograms of the PEDOT-Pt-nanoparticles composite materi...

  13. Electrochemical deposition of platinum nanoparticles on different carbon supports and conducting polymers

    OpenAIRE

    Domínguez Domínguez, Sonia; Arias Pardilla, Joaquín; Berenguer Murcia, Ángel; Morallón Núñez, Emilia; Cazorla Amorós, Diego

    2007-01-01

    Electrodeposition of Pt nanoparticles under potentiostatic conditions was performed on several types of carbon electrode supports: commercial macroporous carbon (a three-dimensional electrode), glassy carbon and graphite. Conducting polymers (poly-aniline and poly-oaminophenol) were also used. The platinum nanoparticles were obtained by different Potential Step Deposition (PSD) methods in 5 mM H2PtCl6 + 0.5 M H2SO4 aqueous solutions. The effect of the final potential, time and num...

  14. Structural characterization and thermally stimulated discharge conductivity (TSDC) study in polymer thin films

    Indian Academy of Sciences (India)

    V S Sangawar; R J Dhokne; A U Ubale; P S Chikhalikar; S D Meshram

    2007-04-01

    The electrical conductivity of naphthalene doped polystyrene (PS) films (? 61.58 m thick) was studied as a function of dopant concentration and temperature. The formation of charge transfer (CT) complexes and strong concentration dependence of carrier mobility point out that the current carriers are transported through doped polymer system via hopping among sites associated with the dopant molecules. The activation energy, a, was calculated from the graph of logvs 103/ plot within low and high temperature regions.

  15. AC magnetic field-assisted method to develop porous carbon nanotube/conducting polymer composites for application in thermoelectric materials

    Science.gov (United States)

    Chuang, Chun-Yu; Yang, Shu-Chian; Chang, Su-Hua; Yang, Ta-I.

    2015-04-01

    Thermoelectric materials are very effective in converting waste heat sources into useful electricity. Researchers are continuing to develop new polymeric thermoelectric materials. The segregated-network carbon nanotube (CNT)- polymer composites are most promising. Thus, the goal of this study is to develop novel porous CNT -polymer composites with improved thermoelectric properties. The research efforts focused on modifying the surface of the CNT with magnetic nanoparticles so that heat was released when subjecting to an AC magnetic field. Subsequently, polymers covered on the surface of the CNT were crosslinked. The porous CNT -polymer composites can be obtained by removing the un-crosslinked polymers. Polydimethylsiloxane polymer was utilized to investigate the effect of porosity and electrical conductivity on the thermoelectric properties of the composites. This AC magnetic field-assisted method to develop porous carbon nanotube/polymer composites for application in thermoelectric materials is introduced for the first time. The advantage of this method is that the electrical conductivity of the composites was high since we can easily to manipulate the CNT to form a conducting path. Another advantage is that the high porosity significantly reduced the thermal conductivity of the composites. These two advantages enable us to realize the polymer composites for thermoelectric applications. We are confident that this research will open a new avenue for developing polymer thermoelectric materials.

  16. Experimental observation of scaling laws for alternating current and direct current conductivity in polymer-carbon nanotube composite thin films

    OpenAIRE

    COLEMAN, JONATHAN NESBIT; BLAU, WERNER; Hutzler, Stefan; DRURY, ANNA

    2002-01-01

    Alternating current (ac) and direct current (dc) conductivities have been measured in polymer-nanotube composite thin films. This was carried out for a range of concentrations of multiwall nanotubes in two polymer hosts, poly(m-phenylenevinylene-co-2,5-dioctyloxyp-phenylenevinylene) (PmPV) and polyvinylalcohol (PVA). In all cases the dc conductivity ?DC was ohmic in the voltage range studied. In general the ac conductivity displayed two distinct regions, a frequency independent region of magn...

  17. Synthesis and proton conductivity studies of doped azole functional polymer electrolyte membranes

    International Nuclear Information System (INIS)

    The development of anhydrous proton-conducting membranes is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 oC). In this work, poly(vinylbenzylchloride), PVBC was produced by free radical polymerization of 4-vinylbenzylchloride and then it was modified with 5-aminotetrazole (ATET) to obtain poly(vinylbenzylaminotetrazole), PVBC-ATET. The composition of the polymer was verified by elemental analysis (EA) and the structure was characterized by FT-IR and 13C NMR spectra. According to the elemental analysis result, PVBC was modified by ATET with 80% yield. The polymer was doped with trifluoromethanesulfonic acid (TA) at various molar ratios, x = 1.25, 2.5, 3.75 with respect to tetrazole unit. The proton transfer from TA to the tetrazole rings was proved with FT-IR spectroscopy. Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 200 oC. Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials. Cyclic voltammetry (CV) study illustrated that the electrochemical stability domain for PVBC-ATET-TA2.5 extends over 3.0 V. The proton conductivity of these materials increased with dopant concentration and the temperature. Maximum proton conductivity of PVBC-ATET-TA2.5 was found to be 0.01 S/cm at 150 oC in the anhydrous state.

  18. Synthesis and proton conductivity studies of doped azole functional polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ozden, Sehmus [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey); Celik, Sevim Unueguer, E-mail: sunugur@fatih.edu.t [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey); Bozkurt, Ayhan [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey)

    2010-12-01

    The development of anhydrous proton-conducting membranes is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 {sup o}C). In this work, poly(vinylbenzylchloride), PVBC was produced by free radical polymerization of 4-vinylbenzylchloride and then it was modified with 5-aminotetrazole (ATET) to obtain poly(vinylbenzylaminotetrazole), PVBC-ATET. The composition of the polymer was verified by elemental analysis (EA) and the structure was characterized by FT-IR and {sup 13}C NMR spectra. According to the elemental analysis result, PVBC was modified by ATET with 80% yield. The polymer was doped with trifluoromethanesulfonic acid (TA) at various molar ratios, x = 1.25, 2.5, 3.75 with respect to tetrazole unit. The proton transfer from TA to the tetrazole rings was proved with FT-IR spectroscopy. Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 200 {sup o}C. Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials. Cyclic voltammetry (CV) study illustrated that the electrochemical stability domain for PVBC-ATET-TA{sub 2.5} extends over 3.0 V. The proton conductivity of these materials increased with dopant concentration and the temperature. Maximum proton conductivity of PVBC-ATET-TA{sub 2.5} was found to be 0.01 S/cm at 150 {sup o}C in the anhydrous state.

  19. Transparent conductive-polymer strain sensors for touch input sheets of flexible displays

    International Nuclear Information System (INIS)

    A transparent conductive polymer-based strain-sensor array, designed especially for touch input sheets of flexible displays, was developed. A transparent conductive polymer, namely poly(3, 4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), was utilized owing to its strength under repeated mechanical bending. PEDOT:PSS strain sensors with a thickness of 130 nm exhibited light transmittance of 92%, which is the same as the transmittance of ITO electrodes widely used in flat panel displays. We demonstrated that the sensor array on a flexible sheet was able to sustain mechanical bending 300 times at a bending radius of 5 mm. The strain sensor shows a gauge factor of 5.2. The touch point on a flexible sheet could be detected from histograms of the outputs of the strain sensors when the sheet was pushed with an input force of 5 N. The touch input could be detected on the flexible sheet with a curved surface (radius of curvature of 20 mm). These results show that the developed transparent conductive polymer-based strain-sensor array is applicable to touch input sheets of mechanically bendable displays.

  20. Polymer Surface Engineering for Efficient Printing of Highly Conductive Metal Nanoparticle Inks.

    Science.gov (United States)

    Agina, Elena V; Sizov, Alexey S; Yablokov, Mikhail Yu; Borshchev, Oleg V; Bessonov, Alexander A; Kirikova, Marina N; Bailey, Marc J A; Ponomarenko, Sergei A

    2015-06-10

    An approach to polymer surface modification using self-assembled layers (SALs) of functional alkoxysilanes has been developed in order to improve the printability of silver nanoparticle inks and enhance adhesion between the metal conducting layer and the flexible polymer substrate. The SALs have been fully characterized by AFM, XPS, and WCA, and the resulting printability, adhesion, and electrical conductivity of the screen-printed metal contacts have been estimated by cross-cut tape test and 4-point probe measurements. It was shown that (3-mercaptopropyl)trimethoxysilane SALs enable significant adhesion improvements for both aqueous- and organic-based silver inks, approaching nearly 100% for PEN and PDMS substrates while exhibiting relatively low sheet resistance up to 0.1 ?/sq. It was demonstrated that SALs containing functional -SH or -NH2 end groups offer the opportunity to increase the affinity of the polymer substrates to silver inks and thus to achieve efficient patterning of highly conductive structures on flexible and stretchable substrates. PMID:25984650

  1. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

    Directory of Open Access Journals (Sweden)

    Parul Chawla

    2014-08-01

    Full Text Available In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO and tri-n-octylphosphine (TOP and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern–Volmer quenching constant (KSV and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor–acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe. Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

  2. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals.

    Science.gov (United States)

    Chawla, Parul; Singh, Son; Sharma, Shailesh Narain

    2014-01-01

    In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe) chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO) and tri-n-octylphosphine (TOP) and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene) polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern-Volmer quenching constant (K SV) and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor-acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe). Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications. PMID:25161859

  3. Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A new finding of tubular array of 10–20 ?m in length and 1–2 ?m in thickness of gel polymer electrolyte (GPE) having 2.2 × 10?3 S cm?1 conductivity is reported. • Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. • GPE based supercapacitor demonstrates high capacitance of 186 F g?1. • Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. • Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. -- Abstract: A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO4 as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10?3 S cm?1 and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g?1 using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge–discharge study of supercapacitor indicated that the device has good stability, high energy density and power density

  4. Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sudhakar, Y.N. [Department of Chemistry, Manipal Institute of Technology, Manipal, Karnataka (India); Selvakumar, M., E-mail: chemselva78@gmail.com [Department of Chemistry, Manipal Institute of Technology, Manipal, Karnataka (India); Bhat, D. Krishna [Department of Chemistry, National Institute of Technology Karnataka, Surathkal, Mangalore (India)

    2014-02-15

    Highlights: • A new finding of tubular array of 10–20 ?m in length and 1–2 ?m in thickness of gel polymer electrolyte (GPE) having 2.2 × 10{sup ?3} S cm{sup ?1} conductivity is reported. • Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. • GPE based supercapacitor demonstrates high capacitance of 186 F g{sup ?1}. • Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. • Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. -- Abstract: A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO{sub 4} as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10{sup ?3} S cm{sup ?1} and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g{sup ?1} using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge–discharge study of supercapacitor indicated that the device has good stability, high energy density and power density.

  5. Photo induced memory devices using conducting polymer, poly(3-hexylthiophene) thin films

    International Nuclear Information System (INIS)

    Photo induced memory devices have been fabricated utilizing conducting polymer, head-to-tail coupled poly(3-hexylthiophene), PHT. The PHT film with Au electrodes at the bottom was coated with ultra thin Al by the thickness of 1 nm on the top. A large increase of conductivity was observed upon light illumination. The increased photoconductivity lasted for several hours after turn off of illumination, indicating photo induced memory effect. The phenomenon is discussed in terms of the persistent photoconduction, which resulted from the electron trapping at Al donor sites in the depletion layer formed near the top of film

  6. Applicability of heminal mechanism to description of radiation-induced conductivity of polymers

    International Nuclear Information System (INIS)

    Numerical calculations of radiation-induced conductivity transitional process under homogeneous and Nable generation of separated ion pairs are carried out for a model dielectric simulating high-pressure polyethylene (HPPE) or polytetrafluoroethylene (PTPE) at the absence of pair overlapping (irradiation low dose). The obtained results are compared with the available experimental data. Additional factor explaining kinetic braking of the pair recombination and the ensuing discription of Langevia mechanism of charge carrier volume recombination is required to correlate the experimental results with the theory of heminal conductivity in HPPE, PTFE and polyprolyelene type polymers. 20 refs., 3 figs., 3 tabs

  7. Induced anisotropy of thermal conductivity of polymer solids under large strains

    Science.gov (United States)

    Peng, S. T. J.; Landel, R. F.

    1975-01-01

    A simple analytical form of induced anisotropy of heat conductivity of initially isotropic polymer solids results from employing the simplified theory of the three-chain model of the non-Gaussian network. The analytical form appears to be valid up to a stretch ratio of 2.65, which is the limit of existing experimental data. The effect of induced anisotropy on the temperature distribution, due to the large deformations, is illustrated for a highly expanded spherical shell and a cylindrical tube under a steady-state heat flow using the derived analytical form of the strain-dependent heat conductivity.

  8. The change in dielectric constant, AC conductivity and optical band gaps of polymer electrolyte film: Gamma irradiation

    International Nuclear Information System (INIS)

    The effects of gamma (?) irradiation on dielectric and optical properties of polymer electrolyte film were investigated. The dielectric constant and ac conductivity increases with ? dose. Also optical band gap decreased from 4.23 to 3.78ev after irradiation. A large dependence of the polymer properties on the irradiation dose was noticed. This suggests that there is a possibility of improving polymer electrolyte properties on gamma irradiation

  9. The change in dielectric constant, AC conductivity and optical band gaps of polymer electrolyte film: Gamma irradiation

    Science.gov (United States)

    Raghu, S.; Subramanya, K.; Sharanappa, C.; Mini, V.; Archana, K.; Sanjeev, Ganesh; Devendrappa, H.

    2014-04-01

    The effects of gamma (?) irradiation on dielectric and optical properties of polymer electrolyte film were investigated. The dielectric constant and ac conductivity increases with ? dose. Also optical band gap decreased from 4.23 to 3.78ev after irradiation. A large dependence of the polymer properties on the irradiation dose was noticed. This suggests that there is a possibility of improving polymer electrolyte properties on gamma irradiation.

  10. Influence of Inorganic Nano-powders on the Structure and Conductive Properties of the Network Polymer Electrolytes for Lithium Batteries

    OpenAIRE

    Yarmolenko O.V.; Yudina A.V.; Tulibaeva G.Z.; Cherniak A.V.; Volkov V.I.; Shestakov A.F.

    2013-01-01

    The paper describes investigation on the network polymer electrolytes based on polyethylene glycol diacrylates and polyester diacrylates PEDA with introduction the nanopowders TiO2, Li2TiO3 and SiO2, with different size and shape. Much attention is paid to effects of nanoparticles additives on the ionic conductivity of network polymer electrolytes. The work is aimed to explanation of the mechanism of additives action on Li+ - ion transport and structural changes of the polymer cha...

  11. Effect of ZrO2 on conductivity of PVC–PMMA–LiBF4–DBP polymer electrolytes

    Indian Academy of Sciences (India)

    S Rajendran; T Uma

    2000-02-01

    The preparation and characterization of composite polymer electrolytes of PVC–PMMA–LiBF4–DBP for different concentrations of ZrO2 have been investigated. FTIR studies indicate complex formation between the polymers, salt and plasticizer. The electrical conductivity values measured by a.c. impedance spectroscopy is found to depend upon the ZrO2 concentration. The temperature dependence of the conductivity of the polymer films seems to obey the VTF relation. The conductivity values are presented and results discussed.

  12. Photo-induced ionic conductivity switching in polymer composite film with azobenzene derivative

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Keiichi; Suzuki, Satsuta; Yokoyama, Masaaki (Chemical Process Engineering, Osaka Univ., Yamada-oka, Suita (Japan))

    1990-08-01

    The polymer composite film consisting of poly(vinyl chloride) (PVC), an azobenzene liquid crystal, lithium perchlorate, and a crown ether has been designed which undergoes photo-induced switching of ionic conductivity by photochromic phase transition. UV light irradiation on the composite film causes isomerization of the azobenzene derivative from the trans to cis isomers accompanied by its phase transition from the crystal to isotropic states, which thus leads to drastic ionic-conductivity increase of the film by more than two orders of magnitude. The enhanced ionic conductivity can be restored to the initial state by visible light irradiation. The photo-induced ionic-conductivity switching was found to be quite reversible.

  13. Dielectric and Ac conduction properties of A Chloro-opianic Polymer Modified by ions Beam Bombardment

    International Nuclear Information System (INIS)

    Dielectric behavior and ac conduction of a chloro-organic material, non- plasticised poly vinyle chloride with poly vinyle alcohol (U PVC/PVA copolymer), irradiated with ions beam have been investigated. The dielectric measurements were performed in the frequency range 100 Hz to 5 MHz and in the temperature range 293-373 K. The variations of the dielectric constant ?, dielectric loss ? and ac conductivity were studied at different frequencies as a function of both temperature and proton dose up to 10''1''5 proton/cm''2. Decreases in ?' and ? and an increase in ac conductivity with dose were observed. The irradiation of the samples results in the formation of charge transfer complexes in the polymer which cause the shift of ?max value towards higher frequency as the dose increases. Dielectric constant and ac conductivity as functions of dose were discussed. Moreover, the temperature dependence of the frequency exponent factor S was obtained

  14. Pressure-induced amorphization of a dense coordination polymer and its impact on proton conductivity

    International Nuclear Information System (INIS)

    The proton conductivity of a dense coordination polymer (CP) was investigated under high-pressure conditions. Impedance measurements under high pressures revealed that the proton conductivity of the CP decreased more than 1000-fold at pressures of 3–7 GPa and that the activation energy for proton conduction almost doubled compared with that at ambient pressure. A synchrotron X-ray study under high pressure identified the amorphization process of the CP during compression, which rationally explains the decrease in conductivity and increase in activation energy. This phenomenon is categorized as reversible pressure-induced amorphization of a dense CP and is regarded as a demonstration of the coupling of the mechanical and electrical properties of a CP

  15. Ionic drift velocity measurement on hot-pressed Ag+ ion conducting glass-polymer electrolytes

    Indian Academy of Sciences (India)

    Angesh Chandra

    2015-12-01

    Ionic drift velocity (d) measurements of a new Ag+ ion conducting glass-polymer electrolytes (GPEs): (1?x) PEO : x[0.8(0.75AgI:0.25AgCl) : 0.2(Ag2 O:V2O5)], where 0 < x < 50 wt%, were reported. GPEs were casted using the hot-press techniques developed in recent times. The composition: 70PEO : 30[0.8(0.75AgI : 0.25AgCl) : 0.2(Ag2O : V2O5)] with conductivity ()? 7.7 × 10?7 S cm?1 was identified as highest conducting composition from the compositional-dependent conductivity studies. The ionic mobility (), mobile ion concentration (), ionic transference number (ion) and ionic drift velocity (d) of GPEs were determined at different temperatures with the help of the d.c. polarization technique and other well-known important relations.

  16. Hybrid nanocomposites based on conducting polymer and silicon nanowires for photovoltaic application

    International Nuclear Information System (INIS)

    Hybrid nanocomposites based on a nanoscale combination of organic and inorganic semiconductors are a promising way to enhance the performance of solar cells through a higher aspect ratio of the interface and the good processability of polymers. Nanocomposites are based on a heterojunction network between poly (2-methoxy-5-(2-ethyhexyl-oxy)-p-phenylenevinylene) (MEH-PPV) as an organic electron donor and silicon nanowires (SiNWs) as an inorganic electron acceptor. Nanowires (NWs) seem to be a promising material for this purpose, as they provide a large surface area for contact with the polymer and a designated conducting pathway whilst their volume is low. In this paper, silicon nanowires are introduced by mixing them into the polymer matrix. Hybrid nanocomposites films were deposited onto ITO substrate by spin coating method. Optical properties and photocurrent response were investigated. Charge transfer between the polymer and SiNWs has been demonstrated through photoluminescence measurements. The photocurrent density of ITO/MEH-PPV:SiNWs/Al structures have been obtained by J–V characteristics. The Jsc value is about 0.39 µA/cm2. - Highlights: • SiNWs synthesis by Vapor–Liquid–Solid (VLS) mechanism. • SiNWs contribution to absorption spectra enhancement of MEH-PPV:SiNWs nanocomposites. • Decrease of PL intensity of MEH-PPV by addition of SiNWs. • Charge transfer process was taken place. • ITO/MEH-PPV:SiNWs/Al structure shows a photovoltaic effect, with a FF of 0.32

  17. Towards TiO2-conducting polymer hybrid materials for lithium ion batteries

    International Nuclear Information System (INIS)

    Nanocomposites of TiO2 (anatase) with polypyrrole (Ppy) or poly(3,4-ethylenedioxythiophene) (PEDOT) were prepared via electrochemical routes. The deposition process of the conducting polymer films was performed in the presence of perchlorate, p-toluenesulphonate (TOS) or bis(trifluoromethylsulphonyl)imide (TFSI) anions in propylene carbonate (PC). The obtained electrode materials were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). An improvement of lithium ion intercalation/de-intercalation properties of titanium(IV) oxide as a result of its interfacing with the polymers is evidenced. This effect was strongly dependent on the thickness of the polymer layer and closely related to the polymer facility for transporting of lithium ion. Polypyrrole properties, in contrast to the PEDOT case, are very sensitive to selection of the substrate material (Pt or Pt/TiO2) during electropolymerization. Polypyrrole deposited on a rough surface exhibits an improvement in its ion exchange abilities. The impact of underlying TiO2 layers on Ppy properties has an indirect (synergic) influence on the effectiveness of lithium ion intercalation into the oxide too. The properties of the composites were discussed also in view of the comparative electrochemical quartz crystal microbalance (EQCM) study focussing on ion transport properties of Ppy and PEDOT.

  18. Normal stiffness calibration of microfabricated tri-layer conducting polymer actuators

    International Nuclear Information System (INIS)

    This paper reports on the stiffness characterization of microfabricated tri-layer conducting polymer (PPy) actuators. The rectangular, polypyrrole microactuators, which could operate both in aqueous and non-aqueous media, were fabricated using an excimer laser ablation technique that provided high throughput production and did not require cleanroom facilities. The microactuators were fixed at one end with electrical contacts and the other was end free to act as an electroactive microcantilever beam. An atomic force microscope (AFM) was used to measure the microactuator deflection under a range of normal forces applied by the AFM cantilever. A modified reference spring constant calibration method was employed to determine the stiffness constants of the microactuators. The stiffness of the microactuators in the electroactive (electrically stimulated) and passive state (no stimulation) were evaluated separately and compared. In doing so, the study presents results leading to the stiffness characterization of the first air-operated polymer microactuators and implementation of a simple, reliable and effective method for directly measuring the spring constant of polymer microactuators. This method is an alternative to the use of mechanical modeling methods, which can be difficult to implement for multi-layer (composite) polymer actuators. Importantly, our results highlight several requirements for using the reference spring method to accurately determine stiffness values of any microcantilever generally fabricated from soft, deformable materials

  19. Precision patterning of conductive polymer nanocomposite using a laser-ablated thin film

    Science.gov (United States)

    Liu, Chao-Xuan; Choi, Jin-Woo

    2012-04-01

    We introduce a simple, reliable and low-cost microfabrication technique utilizing laser ablation of a thin polymer film to pattern polymer nanocomposite at a high resolution. A conductive composite of poly(dimethylsiloxane) (PDMS) and carbon nanotubes (CNTs) was selected due to their wide use in microelectromechanical systems (MEMS) and unique properties including flexibility and piezoresistivity. To pattern nanocomposite, an excimer laser ablated through a thin polyethylene terephthalate film creating mold patterns. PDMS-CNTs nanocomposite was then filled into the mold with excessive amount removed by a smooth-edged tool. Bulk PDMS was poured atop and cured. After debonding devices with relief patterns of polymer nanocomposite could be readily realized. Fabrication conditions were optimized which led to reliable patterning of various microstructures. Detailed surface profiling revealed excellent pattern authenticity and uniformity. Minimal feature size of patterns reached below 20 µm which indicated a significant improvement from prior reports. Moreover, the presented technique required only a software design to rapidly generate new patterns, thereby eliminating costly hardware such as lithography mask, stamp and clean room. Fabrication time and cost could be consequently reduced—ideal for lab prototyping purposes. Sensor examples are discussed to demonstrate versatile applications of polymer nanocomposite in MEMS.

  20. Correlation between ionic conductivity and fluidity of polymer gel electrolytes containing NH4CF3SO3

    Indian Academy of Sciences (India)

    Harinder Pal Singh; Rajiv Kumar; S S Sekhon

    2005-08-01

    Nonaqueous polymer gel electrolytes containing ammonium triflate (NH4CF3SO3) and dimethylacetamide (DMA) with polymethylmethacrylate (PMMA) as the gelling polymer have been synthesized which show high value of conductivity (? 10-2 S/cm) at 25°C. The conductivity of polymer gel electrolytes containing different concentrations of NH4CF3SO3 shows a small decrease with the addition of PMMA and this has been correlated with the variation of fluidity of these gel electrolytes. The small decrease in conductivity with PMMA addition shows that polymer plays the role of stiffener and this is supported by FTIR results which also indicates the absence of any active interaction between polymer and NH4CF3SO3 in these gel electrolytes.

  1. Conducting polymers, buckminsterfullerenes, and carbon nanotubes: optoelectronic materials based on architectural diversity of the ?-conjugated structure

    International Nuclear Information System (INIS)

    Recent discovery of superconductivity in self assembled poly(3-hexylthiophene) two-dimensional conjugated sheets indicates the possible applications of plastics even in superconducting optoelectronic devices. Just as the discovery of C60 has created an entirely new branch of carbon chemistry, the subsequent discovery of carbon nanotubes by lijima in 1991 opened up a new era in material science and nanotechnology. These elongated nanotubes consist of carbon hexagons arranged in a concentric manner with both ends normally capped by fullerene-like structures containing pentagons. Having a conjugated all-carbon structure with unusual molecular symmetries, fullerenes and carbon nanotubes also show interesting electronic, photonic, magnetic and mechanical properties, attractive for various applications, including optical limiters, photovoltaic cells and field emitting displays. For most of the above applications, it is highly desirable to prepare ordered/micropatterned conducting polymers, fullerenes, and carbon nanotubes. Although the microfabrication of conducting polymers has been an active research area for some years, it is a very recent development for fullerenes and carbon nanotubes. Recently, we doped polyaniline (PANI) with a hydrogensulfated fullerenol derivative containing multiple -OSO3H groups (i.e. C60(OH)6(OSO3H)6) to produce three-dimensional PANI conductors with a room-temperature conductivity of up to 100 S cm-1. This value of conductivity is about six orders of magnitude higher than the typical value for C60 doped conducting polymers. Later, in collaboration with Wan's group at the Chinese Academy of Sciences, we have also synthesized PANI nanotubes via a self assembled C60(OH)6(OSO3H)6 supramolecular template using (NH4)2S2O8 as an oxidant. These results, together with the more recent discovery of a hollow sphere, self assembled by the potassium salt of pentaphenyl fullerene (Ph5C60K) in water, clearly indicate that supramolecular chemistry has broadened the scope for preparing new optoelectronic materials from the ?-conjugated entities. Copyright (2001) CSIRO Australia

  2. Bionanocompósitos preparados por incorporação de nanocristais de celulose em polímeros biodegradáveis por meio de evaporação de solvente, automontagem ou eletrofiação / Bio-based nanocomposites obtained by incorporation of cellulose nanocrystals into biodegradable polymers through casting, layer-by-layer or electrospinning methods

    Scientific Electronic Library Online (English)

    Fabiano Vargas, Pereira; Everton Luiz de, Paula; João Paulo de, Mesquita; Alessandra de Almeida, Lucas; Valdir, Mano.

    Full Text Available [...] Abstract in english This review reports the preparation and characterization of bionanocomposites based on biodegradable polymers reinforced with cellulose nanocrystals (CNC) described in the literature. The outstanding potential of cellulose nanocrystals as reinforcement fillers of biodegradable polymers is presented [...] with an emphasis on the solution casting process, which is an appropriate method to investigate the physico-chemical effects of the incorporation of CNC into the polymeric matrices. Besides solution casting, other small scale methods such as electrospinning and layer-by-layer are also covered.

  3. X-ray evaluation of the boundary between polymer electrolyte and platinum and carbon functionalization to conduct protons in polymer electrolyte fuel cells

    Science.gov (United States)

    Oka, Kazuki; Ogura, Yuta; Izumi, Yasuo

    2014-07-01

    In polymer electrolyte fuel cells (PEFCs), it is important to secure proximate diffusion paths of reactants and electrons. One approach is to optimize the boundary between polymer electrolyte and Pt nanoparticle surface. Based on synchrotron X-ray absorption fine structure to monitor directly the status of catalysts in PEFCs, it was found that Pt sites were reduced to Pt0 by alcohols contained in polymer electrolyte dispersion solution during the preparation of cathode of PEFC. As in membrane electrolyte assembly, only the Pt sites not covered by polymer electrolyte re-oxidized to Pt2+/4+. Thus, the interface between Pt and polymer electrolyte was evaluated. The other approach is to functionalize carbon surface with sulfonate/sulfate group to conduct protons. Similar level of proton conductivity was observed in current-voltage dependence compared to using polymer electrolyte, but polymer electrolyte was advantageous to lose less voltage for activation. Based on this comparison, optimum catalyst on cathode is proposed comprising surface sulfonate/sulfate group on carbon mixed with polymer electrolyte. Further optimization of cathode catalyst is proposed to functionalize carbon with sulfonate group linked to fluorocarbon branch.

  4. Conductive Circuit Containing a Polymer Composition Containing Thermally Exfoliated Graphite Oxide and Method of Making the Same

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2014-01-01

    A conductive circuit containing a polymer composite, which contains at least one polymer and a modified graphite oxide material, containing thermally exfoliated graphite oxide having a surface area of from about 300 m(sup.2)/g to 2600 m(sup.2)/g, and a method of making the same.

  5. Controllable growth of nanoscale conductive filaments in solid-electrolyte-based ReRAM by using a metal nanocrystal covered bottom electrode.

    Science.gov (United States)

    Liu, Qi; Long, Shibing; Lv, Hangbing; Wang, Wei; Niu, Jiebin; Huo, Zongliang; Chen, Junning; Liu, Ming

    2010-10-26

    Resistive memory (ReRAM) based on a solid-electrolyte insulator is a promising nanoscale device and has great potentials in nonvolatile memory, analog circuits, and neuromorphic applications. The underlying resistive switching (RS) mechanism of ReRAM is suggested to be the formation and rupture of nanoscale conductive filament (CF) inside the solid-electrolyte layer. However, the random nature of the nucleation and growth of the CF makes their formation difficult to control, which is a major obstacle for ReRAM performance improvement. Here, we report a novel approach to resolve this challenge by adopting a metal nanocrystal (NC) covered bottom electrode (BE) to replace the conventional ReRAM BE. As a demonstration vehicle, a Ag/ZrO(2)/Cu NC/Pt structure is prepared and the Cu NC covered Pt BE can control CF nucleation and growth to provide superior uniformity of RS properties. The controllable growth of nanoscale CF bridges between Cu NC and Ag top electrode has been vividly observed by transmission electron microscopy (TEM). On the basis of energy-dispersive X-ray spectroscopy (EDS) and elemental mapping analyses, we further confirm that the chemical contents of the CF are mainly Ag atoms. These testing/metrology results are consistent with the simulation results of electric-field distribution, showing that the electric field will enhance and concentrate on the NC sites and control location and orientation of Ag CFs. PMID:20853865

  6. Conducting polymers - mechanisms of cationic sensitivity and the methods of inducing thereof

    International Nuclear Information System (INIS)

    Highlights: • The open-circuit cationic sensitivity of conducting polymers is discussed. • Inducing sensitivity by p-doping with metal complexing ligands (MCL) is shown. • Using MCL allows obtaining CP films with sensitivity independent of oxidation state. - Abstract: Different methods for inducing open-circuit cationic sensitivity of the conducting polymer (CP) films doped with Metal Complexing Ligands (MCL) are presented. Selected MCLs have the R-(MCG-H)p(SO3H)n, structure and contain bulky organic group (R), “n” sulphonate groups responsible for CP doping and “p” metal complexing groups (-MCG-H) responsible for formation of the complexes with a narrow group of cations. MCLs molecules introduced to CP layer as bulky doping anions are immobilized inside CP layer and preserve their chemical properties known from water chemistry. Similarly, as ionophores, they can form complexes inside CP membrane with selected cations only. It was shown that formation of the complex inside the polymer layer is necessary for inducing preferred open-circuit sensitivity of the CP membrane. Various, efficient methods of the CP-MCL film sensitization towards calcium, magnesium as well as copper, cadmium, lead or zinc cations are presented

  7. Microtexturing of the conductive PEDOT:PSS Polymer for superhydrophobic organic electrochemical transistors

    KAUST Repository

    Gentile, Francesco

    2014-01-22

    Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry and materials science to obtain an advanced device where, on account of the superhydrophobicity of the system, the solutions of interest can be manipulated and, on account of the conductive PEDOT:PSS polymer, the charged molecules dispersed inside can be quantitatively measured. This original substrate preparation allowed to perform electrochemical measurements on ionized species in solution with decreasing concentration down to 10 -7 molar. Moreover, it was demonstrated the ability of the device of realizing specific, combined time and space resolved analysis of the sample. Collectively, these results demonstrate how a tight, interweaving integration of different disciplines can provide realistic tools for the detection of pathologies. The scheme here introduced offers breakthrough capabilities that are expected to radically improve both the pace and the productivity of biomedical research, creating an access revolution. 2014 Francesco Gentile et al.

  8. Dielectric properties and conductivity of carbon nanofiber/semi-crystalline polymer composites

    International Nuclear Information System (INIS)

    The properties of semi-crystalline polymer nanocomposites are affected by the nanofillers directly and indirectly, as two phases, i.e., crystalline and amorphous, exist in the polymer. The effects of nanofillers on the two phases could be competitive. The dielectric properties and conductivity of carbon nanofibers (CNF)/semi-crystalline polymer nanocomposites are studied in this paper. CNF/polypropylene (PP) nanocomposites are prepared in experiment by melt blending. The resulting morphology and crystalline structure are characterized by means of differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy. The PP nanocomposite containing 5 wt.% CNF exhibits a surprisingly high dielectric constant under wide sweep frequencies attended by low dielectric loss. Its dielectric constant is >600 under lower frequency, and remains >200 at a frequency of 4000 Hz. The electrical and thermal conductivities of the nanocomposites are studied, and enhancements are seen with increased CNF content. Theoretical analyses on the physical properties are carried out by applying the existing models. Research results indicate that a common commercial plastic with good comprehensive performance, which exhibited the potential for applications in advanced electronics, was obtained by a simple industry benign technique

  9. Fast prototyping of conducting polymer microelectrodes using resistance-controlled high precision drilling

    DEFF Research Database (Denmark)

    Kafka, Jan Robert; Geschke, Oliver

    2011-01-01

    We present a straightforward method for fast prototyping of microelectrode arrays in the highly conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Microelectrode arrays were produced by electrical resistance-controlled microdrilling through an insulating polymer layer (TOPAS® 5013) covering a PEDOT layer. The sudden drop in electrical resistance between the metal drill and the PEDOT layer upon physical contact was employed as stop criterion for the drilling process. Arrays of 3×3 microelectrodes of diameter 30?m or 100?m, respectively, and having center-to-center electrode spacings of 130?m and 300?m, respectively, were fabricated. Their functionality was verified by chronoamperometry on potassium ferro-/ferricyanide. Comparison of the experimentally obtained results to finite element modeling of the respective electrode configurations shows that the conducting polymer electrodes approach the steady state currents predicted from modeling, but at a much slower rate than expected. This is shown to be caused by the use of electroactive PEDOT electrodes. Subtraction of the latter contribution gives approach to steady state currents within a few seconds, which is in very good agreement with the modeled response time.

  10. Preparation and study of conductivity in lithium salt complexes of mixed MEEP : PEO polymer electrolytes

    Indian Academy of Sciences (India)

    G Saibaba; D Srikanth; A Ramachandra Reddy

    2004-02-01

    Poly(ethylene oxide)–LiX complexes and poly[bis(methoxy ethoxy ethoxide) phosphazene]–LiX complexes of polymer thin films were prepared. Conductivity measurements were carried out and the values were found to lie between 10-8 and 1.7 × 10-5 (S/cm). MEEP : LiX salts showed higher conductivity than PEO–LiX salts despite lower dimensional stability. For enhancing stability and conductivity, MEEP–PEO : (LiX)$_n$ systems were prepared and conductivity measurements carried out. Further the MEEP/PEO : (LiX)$_n$ was doped with Al2O3 and TiO2 nanocomposite ceramic fillers and the conductivity was studied. The conductivity vs temperature plots showed the enhancement of conductivity with TiO2 added nanocomposite ceramic fillers. The enhanced conductivity is explained on the basis of the effect of local structural modification-promoting localized amorphous region-for enhancement of the Li+ ion transport.

  11. Effect of casting solvent interactions on proton conductivity in sulfonated polymer (PEEK) proton exchange membranes

    International Nuclear Information System (INIS)

    The proton conductivity of solvent-cast proton exchange membranes (PEM) prepared from sulfonated poly(ether ether ketone) (SPEEK) was found to be sensitive to the choice of casting solvent and the membrane drying conditions. Using proton nuclear magnetic resonance (NMR) spectroscopy, several factors were shown to affect proton conductivity in PEMs. NMR revealed the formation of strong interactions between SPEEK polymer and the casting solvents dimethylformamide (DMF) and dimethyl cetamide (DMAc), commonly used in PEM preparation. DMF readily hydrogen-bonds with the polymers' sulfonic acid groups starting at temperatures as low as 60oC. However, DMAc is much less susceptible to hydrogen bonding, which occurs only above 100oC. Both DMF and DMAc solvent interactions with SPEEK during PEM preparation significantly affect the proton conductivity properties. In addition, both solvents are prone to thermal decomposition resulting in dimethylamine which also strongly hydrogen-bonds with SPEEK. The presence of residual sulfuric acid originating from SPEEK preparation has a catalytic effect on the thermal degradation of DMF and DMAc. Under high temperature treatment of films, residual sulfuric acid reacts with both DMF and DMAc, causing their degradation resulting in the formation of N,N-dimethylaminium hydrogensulfate which is also believed to have a negative effect on proton conductivity. (author)

  12. Conductivity and adhesion enhancement in low-temperature processed indium tin oxide/polymer nanocomposites

    International Nuclear Information System (INIS)

    We report on the conductivity and adhesion enhancement of indium tin oxide (In2O3:Sn; ITO) nanoparticle films by the application of polymers as matrix material. We fabricated ITO layers at a maximum process temperature of 130 oC by modifying and spin-coating nanoparticulate ITO dispersions. Dispersions containing the organic film-forming agent polyvinylpyrrolidone (PVP) and the organofunctional coupling agent 3-methacryloxypropyltrimethoxysilane (MPTS) have been developed to obtain transparent and conducting coatings on substrates which do not withstand high process temperatures like polymers or already processed glasses. The layers were cured by UV-irradiation as well as by low-temperature heat treatment (T = 130 oC) in air and under forming gas atmosphere (N2/H2). The influence of the additives on the electrical, optical, morphological and mechanical layer properties is reported. Compared to best pure ITO layers (3.1 ?-1 cm-1), the ITO-MPTS-PVP nanocomposite coatings exhibit a conductance of 9.8 ?-1 cm-1. Stable sheet resistances of 750 ?/? at a coexistent transmittance of 86% at 550 nm for a layer thickness of about 1.3 ?m were achieved. The conductance enhancement is a consequence of the consolidation of the ITO nanoparticle network due to the acting shrinkage forces caused either by drying in the case of PVP or UV-irradiation induced condensation and polymerization reactions in the case of MPTS.

  13. Contribution to the electromagnetic study of conducting polymers and chiral structures

    International Nuclear Information System (INIS)

    In this work, an electromagnetic characterisation of organic absorptive materials partially made of conductive polymer is presented. Poly-pyrrole-Teflon alloys containing from 0 to 20 pc (in volume) poly-pyrrole were prepared and characterised from dc to 6 GHz. The complex permittivity shows that these materials are absorptive; the dielectric properties strongly depend on the composition and are correctly modelled by a percolation law. A dielectric relaxation was observed for the conductive alloys and this phenomenon is interpreted as the result of an electronic conduction process insured by a charged carriers hopping. A model was developed; it is in good agreement with these results. The difference between the low and high frequency behaviour is also underlined. Microwave chiral structures were manufactured. A cholesteric arrangement of uniaxial slabs was measured in transmission between 4 and 6 GHz; the experimental results are correctly modelled by cascading quadrupolar scattering matrices. New chiral materials were prepared by mixing millimetric helices made of poly-pyrrole with an insulating matrix. These materials exhibit a rotatory power and a good absorption of electromagnetic waves which is connected to the poly-pyrrole concentration. The interest in using conductive polymers to design absorptive chiral materials in the microwave domain is put in evidence and the experimental results are in good agreement with a numerical model; nevertheless, the optimisation of these materials remains difficult. (author)

  14. Investigation of mechanical and conductive properties of shape memory polymer composite (SMPC)

    Science.gov (United States)

    Leng, Jinsong; Lan, Xin; Lv, Haibao; Zhang, Dawei; Liu, Yanju; Du, Shanyi

    2007-04-01

    This paper is concerned about an investigation of mechanical and electrical conductive properties of carbon fiber fabric reinforced shape memory polymer composite (SMPC). The shape memory polymer (SMP) is a thermoset styrene-based resin. SMP is a promising smart material, which is under intensive investigation at present. Its primary advantages over other smart materials are the high strain capacity (200% reversible strain), low density and low cost etc.. But its major drawbacks are low strength, low modulus and low recovery stress. So the fiber reinforced SMPC was naturally considered to be investigated in this paper, which may overcome the disadvantages mentioned above. The investigation was conducted with experimental methods: Dynamic Mechanical Analyzer (DMA), static and mechanical cycle loading tests, microscope observation of microstructural deformation mechanism, conductivity and shape recovery tests. Results indicated that SMPC showed higher glass transition temperature (T g) than neat SMP and improved the storage modulus, bending modulus, strength and resistance against relaxation and creep. Both fiber microbuckling and fracture of SMPC were observed after the static 3-ponit bending test at the constant room temperature. SMPC showed favorable recovery performances during thermomechanical cycles of the bending recovery test and the fiber microbuckling was obvious. Moreover, the conductive SMPC of this study experienced low electrical resistivity and performed a good shape memory effect during numerous thermomechanical cycles.

  15. Energy level alignment at interfaces with pentacene: metals versus conducting polymers

    Science.gov (United States)

    Koch, N.; Elschner, A.; Johnson, R. L.; Rabe, J. P.

    2005-05-01

    Ultraviolet photoemission spectroscopy was used to determine the work function ? and the hole injection barriers ?h of interfaces formed between pentacene and two fundamentally different electrode materials: (i) conductive polymers comprising poly(3,4-ethylenedioxythiophene) and sulfonate moieties, and (ii) Au with chemisorbed Cl. ? of these substrates before pentacene deposition covers a wide range of 4.25-5.15 eV for the polymers, and extends to 5.8 eV for Au-Cl. Despite this huge variation in ?, ?h after pentacene deposition is found to be almost identical for all cases (?0.35 eV). The mechanism responsible for ?h being independent of initial surface ? is proposed to be an interfacial charge transfer reaction leading to cationic pentacene species. These findings are compared to interfaces between pentacene and clean metal surfaces, where ?h was found to decrease with increasing substrate ?.

  16. Energy level alignment at interfaces with pentacene: metals versus conducting polymers

    International Nuclear Information System (INIS)

    Ultraviolet photoemission spectroscopy was used to determine the work function phi and the hole injection barriers ?h of interfaces formed between pentacene and two fundamentally different electrode materials: (i) conductive polymers comprising poly(3,4-ethylenedioxythiophene) and sulfonate moieties, and (ii) Au with chemisorbed Cl. phi of these substrates before pentacene deposition covers a wide range of 4.25-5.15 eV for the polymers, and extends to 5.8 eV for Au-Cl. Despite this huge variation in phi, ?h after pentacene deposition is found to be almost identical for all cases (?0.35 eV). The mechanism responsible for ?h being independent of initial surface phi is proposed to be an interfacial charge transfer reaction leading to cationic pentacene species. These findings are compared to interfaces between pentacene and clean metal surfaces, where ?h was found to decrease with increasing substrate phi

  17. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    DEFF Research Database (Denmark)

    Andresen, Kristian; Hansen, Morten

    2010-01-01

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstrate the use of AC voltage for electroporation by applying a 1 kHz, +/- 50 V square pulse train to the electrodes and show delivery of polynucleotide fluorescent dye in 46% of human acute monocytic leukemia cells passing the constriction.

  18. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    International Nuclear Information System (INIS)

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstrate the use of AC voltage for electroporation by applying a 1 kHz, ±50 V square pulse train to the electrodes and show delivery of polynucleotide fluorescent dye in 46% of human acute monocytic leukemia cells passing the constriction.

  19. Photovoltaic Cells involving Nonconjugated Conductive Polymer, Iodine-doped cis-Polyisoprene (Natural Rubber)

    Science.gov (United States)

    Jaju, S.; Thakur, M.

    2014-03-01

    Photovoltaic cells have been fabricated using titanium dioxide/doped cis-polyisoprene/carbon on ITO glass-substrates. Photocurrents and photo-voltages for different intensities of light (from a white light bulb, emission at 300-700 nm) have been measured. Use of the iodine-doped nonconjugated conductive polymer film (absorption ~ 250 to 700 nm) has led to significant enhancement of photocurrent compared to previous reports which included undoped polymer in a different cell-structure. A maximum photocurrent of about 0.20 mA was observed for a light intensity of ~ 5 mW/cm2. The maximum photo-voltage as observed was about 0.70 V for the same light intensity. Natural rubber being inexpensive these cells may provide cheaper alternatives to other reported cell structures.

  20. Visualization of Ion Conductivity: Vapochromic Luminescence of an Ion-Conductive Ruthenium(II) Metalloligand-Based Porous Coordination Polymer.

    Science.gov (United States)

    Watanabe, Ayako; Kobayashi, Atsushi; Saitoh, Erika; Nagao, Yuki; Yoshida, Masaki; Kato, Masako

    2015-12-01

    We synthesized a new porous coordination polymer {La1.75(OH)1.25[Ru(dcbpy)3]·16H2O} (La7-[4Ru]4; H2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) composed of a luminescent ruthenium(II) metalloligand [Ru(4,4'-dcbpy)3](4-) and La(3+) cations. X-ray analysis for La7-[4Ru]4 revealed that the La(3+) cations and [4Ru] metalloligands are crystallized in a molar ratio of 7:4 with OH(-) counteranions and a void fraction of ?25.5%. Interestingly, La7-[4Ru]4 shows a reversible structural transition triggered by water ad/desorption, which affects not only the triplet metal-to-ligand charge-transfer ((3)MLCT) emission energy but also the ion conductivity in the solid state. This correlation suggests that La7-[4Ru]4 is an interesting material that enables visualization of the ion conductivity via the (3)MLCT emission energy. PMID:26599494

  1. Composites materials of graphene derivatives and electrically conducting polymers and their application in solid-state ion-selective electrodes.

    Czech Academy of Sciences Publication Activity Database

    Lindfors, T.; Österholm, A.; Boeva, Z.; Kauppila, J.; Bober, Patrycja; Milakin, K.; Gyurcsányi, R. E.

    Toulouse : Phantoms Foundation, 2014. s. 166-167. [International Conference & Exhibition Graphene 2014. 06.05.2014-09.05.2014, Toulouse] Institutional support: RVO:61389013 Keywords : conducting polymers * graphene materials Subject RIV: CD - Macromolecular Chemistry

  2. Mesoscale Origin of the Enhanced Cycling-Stability of the Si-Conductive Polymer Anode for Li-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Meng; Xiao, Xingcheng; Liu, Gao; Thevuthasan, Suntharampillai; Baer, Donald R.; Zhang, Jiguang; Liu, Jun; Browning, Nigel D.; Wang, Chong M.

    2014-01-14

    Electrode used in lithium-ion battery is invariably a composite of multifunctional components. The performance of the electrode is controlled by the interactive function of all components at mesoscale. Fundamental understanding of mesoscale phenomenon sets the basis for innovative designing of new materials. Here we report the achievement and origin of a significant performance enhancement of electrode for lithium ion batteries based on Si nanoparticles wrapped with conductive polymer. This new material is in marked contrast with conventional material, which exhibit fast capacity fade. In-situ TEM unveils that the enhanced cycling stability of the conductive polymer-Si composite is associated with mesoscale concordant function of Si nanoparticles and the conductive polymer. Reversible accommodation of the volume changes of Si by the conductive polymer allows good electrical contact between all the particles during the cycling process. In contrast, the failure of the conventional Si-electrode is probed to be the inadequate electrical contact.

  3. Evaluation of interactive effects on the ionic conduction properties of polymer gel electrolytes.

    Science.gov (United States)

    Saito, Yuria; Okano, Miki; Kubota, Keigo; Sakai, Tetsuo; Fujioka, Junji; Kawakami, Tomohiro

    2012-08-23

    Ionic mobility of electrolyte materials is essentially determined by the nanoscale interactions, the ion-ion interactions and ion-solvent interactions. We quantitatively evaluated the interactive situation of the lithium polymer gel electrolytes through the measurements of ionic conductivity and diffusion coefficients of the mobile species of the lithium polymer electrolytes. The interactive force between the cation and anion in the gel depended on the mixing ratio of the binary solvent, ethylene carbonate plus dimethyl carbonate (EC/DMC). The gel with the solvent (3:7 EC:DMC) showed minimal cation-anion interaction, which is the cause of the highest ionic mobility compared with those of the other gels with different solvents. This suggests that the cation-anion interaction does not simply depend on the dielectric constant of the solvent but is associated with the solvation condition of the lithium. In the case of the gel with the 3:7 EC/DMC solvent, most of the EC species strongly coordinate to a lithium ion, forming the stable solvated lithium, Li(EC)(3)(+), and there are no residual EC species for exchange with them. As a result, the solvating EC species would be a barrier that restricts the anion attack to the lithium leading to the smallest cation-anion interaction. On the other hand, interaction between the cation and polar sites, hydroxyl and oxygen groups of ether of the polyvinyl butyral (PVB) and polyethylene oxide (PEO) polymer, respectively, in the gels was another dominant factor responsible for cation mobility. It increased with increasing polar site concentration per lithium. In case of the PVB gels, cation-anion interaction increased with an increasing polymer fraction of the gel contrary to the independent feature of PEO gels with the change of the polymer fraction. This indicates that the cation-anion interaction is associated with the polymer structure of the gel characterized by the kind and configuration of polar groups, molecular weight, and network morphology of the polymer. PMID:22831401

  4. Reversible light-controlled conductance switching of azobenzene-based metal/polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Pakula, Christina; Zaporojtchenko, Vladimir; Strunskus, Thomas; Faupel, Franz [Institut fuer Materialwissenschaft-Materialverbunde, Technische Fakultaet der Christian-Albrechts-Universitaet zu Kiel, Kaiserstrasse 2, D-24143 Kiel (Germany); Zargarani, Dordaneh; Herges, Rainer, E-mail: ff@tf.uni-kiel.de [Otto-Diels-Institut, CAU Kiel, Otto-Hahn-Platz 4, D-24118 Kiel (Germany)

    2010-11-19

    We present a new concept of light-controlled conductance switching based on metal/polymer nanocomposites with dissolved chromophores that do not have intrinsic current switching ability. Photoswitchable metal/PMMA nanocomposites were prepared by physical vapor deposition of Au and Pt clusters, respectively, onto spin-coated thin poly(methylmethacrylate) films doped with azo-dye molecules. High dye concentrations were achieved by functionalizing the azo groups with tails and branches, thus enhancing solubility. The composites show completely reversible optical switching of the absorption bands upon alternating irradiation with UV and blue light. We also demonstrate reversible light-controlled conductance switching. This is attributed to changes in the metal cluster separation upon isomerization based on model experiments where analogous conductance changes were induced by swelling of the composite films in organic vapors and by tensile stress.

  5. Assembly of three coordination polymers based on a sulfonic-carboxylic ligand showing high proton conductivity.

    Science.gov (United States)

    Zhao, Shu-Na; Song, Xue-Zhi; Zhu, Min; Meng, Xing; Wu, Lan-Lan; Song, Shu-Yan; Wang, Cheng; Zhang, Hong-Jie

    2015-01-21

    Three new coordination polymers (CPs)/metal-organic frameworks (MOFs) with different structures have been synthesized using 4,8-disulfonyl-2,6-naphthalenedicarboxylic acid (H4L) and metal ions, Cu(2+), Ca(2+) and Cd(2+). The Cu compound features a one-dimensional chain structure, further extending into a 2D layer network through H-bond interactions. Both the Ca and Cd compounds show 3D frameworks with (4,4)-connected PtS-type topology and (3,6)-connected bct-type topology, respectively. These CPs/MOFs all exhibit proton conduction behavior, especially for the Cu compound with a proton conductivity of 3.46 × 10(-3) S cm(-1) at 368 K and 95% relative humidity (RH). Additionally, the activation energy (Ea) has also been investigated to deeply understand the proton-conduction mechanism. PMID:25406590

  6. Ultrafast photo-conductivity in BAMH-PPV polymer thin-films

    Science.gov (United States)

    Liang, H. Y.; Cao, W. L.; Du, M.; Kim, Y.; Herman, W. N.; Lee, C. H.

    2006-02-01

    The carrier life time in poly(2,5-bis[ N-methyl- N-hexylamino]phenylene vinylene (BAMH-PPV) is measured by photo-conductive sampling. A systematic study of the influence of both external bias electric field and illumination intensity on the photo-conductance of the polymer is carried out. The photo-conductance remained roughly constant with the applied electric field up to 6 × 10 5 V/cm. Electric pulsewidths of 2 ps were measured. The transient carrier mobility is calculated. For 93 nm thick film the lower limit is estimated to be 0.24 (cm 2/V s) when assuming unity quantum efficiency. This transient mobility value could be 480 (cm 2/V s) when taking quantum efficiency to be 0.05% according to Hendry et al. [E. Hendry, M. Koeberg, J. M. Schins, L.D.A. Siebbeles and M. Bonn, Phys. Rev. B. 70 (2004) 033202].

  7. Carbon Nanotube/Conductive Additive/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

    Science.gov (United States)

    Smith, Joseph G., Jr.; Watson, Kent A.; Delozier, Donavon M.; Connell, John W.

    2003-01-01

    Thin film membranes of space environmentally stable polymeric materials possessing low color/solar absorptivity (alpha) are of interest for potential applications on Gossamer spacecraft. In addition to these properties, sufficient electrical conductivity is required in order to dissipate electrostatic charge (ESC) build-up brought about by the charged orbital environment. One approach to achieve sufficient electrical conductivity for ESC mitigation is the incorporation of single wall carbon nanotubes (SWNTs). However, when the SWNTs are dispersed throughout the polymer matrix, the nanocomposite films tend to be significantly darker than the pristine material resulting in a higher alpha. The incorporation of conductive additives in combination with a decreased loading level of SWNTs is one approach for improving alpha while retaining conductivity. Taken individually, the low loading level of conductive additives and SWNTs is insufficient in achieving the percolation level necessary for electrical conductivity. When added simultaneously to the film, conductivity is achieved through a synergistic effect. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

  8. Quantifying Molecular-Level Cell Adhesion on Electroactive Conducting Polymers using Electrochemical-Single Cell Force Spectroscopy

    Science.gov (United States)

    Zhang, Hongrui; Molino, Paul J.; Wallace, Gordon G.; Higgins, Michael J.

    2015-09-01

    Single Cell Force Spectroscopy was combined with Electrochemical-AFM to quantify the adhesion between live single cells and conducting polymers whilst simultaneously applying a voltage to electrically switch the polymer from oxidized to reduced states. The cell-conducting polymer adhesion represents the non-specific interaction between cell surface glycocalyx molecules and polymer groups such as sulfonate and dodecylbenzene groups, which rearrange their orientation during electrical switching. Single cell adhesion significantly increases as the polymer is switched from an oxidized to fully reduced state, indicating stronger cell binding to sulfonate groups as opposed to hydrophobic groups. This increase in single cell adhesion is concomitant with an increase in surface hydrophilicity and uptake of cell media, driven by cation movement, into the polymer film during electrochemical reduction. Binding forces between the glycocalyx and polymer surface are indicative of molecular-level interactions and during electrical stimulation there is a decrease in both the binding force and stiffness of the adhesive bonds. The study provides insight into the effects of electrochemical switching on cell adhesion at the cell-conducting polymer interface and is more broadly applicable to elucidating the binding of cell adhesion molecules in the presence of electrical fields and directly at electrode interfaces.

  9. Increasing ionic conductivity and mechanical strength of a plastic electrolyte by inclusion of a polymer

    International Nuclear Information System (INIS)

    In this contribution we present a soft matter solid electrolyte which was obtained by inclusion of a polymer (polyacrylonitrile, PAN) in LiClO4/LiTFSI-succinonitrile (SN), a semi-solid organic plastic electrolyte. Addition of the polymer resulted in considerable enhancement in ionic conductivity as well as mechanical strength of LiX-SN (X = ClO4, TFSI) plastic electrolyte. Ionic conductivity of 92.5%-[1 M LiClO4-SN]:7.5%-PAN (PAN amount as per SN weight) composite at 25 deg. C recorded a remarkably high value of 7 x 10-3 ?-1 cm-1, higher by few tens of order in magnitude compared to 1 M LiClO4-SN. Composite conductivity at sub-ambient temperature is also quite high. At -20 deg. C, the ionic conductivity of (100 - x)%-[1 M LiClO4-SN]:x%-PAN composites are in the range 3 x 10-5-4.5 x 10-4 ?-1 cm-1, approximately one to two orders of magnitude higher with respect to 1 M LiClO4-SN electrolyte conductivity. Addition of PAN resulted in an increase of the Young's modulus (Y) from Y ? 0 for LiClO4-SN to a maximum of 0.4 MPa for the composites. Microstructural studies based on X-ray diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy suggest that enhancement in composite ionic conductivity is a combined effect of decrease in crystallinity and enhanced trans conformer concentration

  10. Investigation of the Ionic conductivity and dielectric measurements of poly (N-vinyl pyrrolidone)-sulfamic acid polymer complexes

    International Nuclear Information System (INIS)

    Polymer electrolyte complexes of poly (N-vinyl pyrrolidone) (PVP)-sulfamic acid (NH2SO3H) were prepared by a familiar solution casting method with different molar concentrations of PVP and sulfamic acid. The interaction between PVP and NH2SO3H was confirmed by Fourier transform infrared spectroscopy analysis. Laser microscopy analysis was used to study the surface morphology of the polymer complexes. The glass transition temperature (Tg) and the melting temperature (Tm) of polymer complexes were computed from Differential scanning calorimetric studies. AC impedance spectroscopic measurements revealed that the polymer complex, 97 mol% PVP-3 mol% NH2SO3H shows higher ionic conductivity with two different activation energies above and below the glass transition temperature (Tg). Dielectric studies confirmed that the dc conduction mechanism has dominated in the polymer complexes. The value of power law exponent (n) confirmed the translational motion of ions from one site to another vacant site in these complexes

  11. Effect of silver nanoparticles on the DC conductivity in chitosan-silver triflate polymer electrolyte

    International Nuclear Information System (INIS)

    A solid polymer electrolyte composed of chitosan and silver triflate (AgCF3SO3) has been prepared by the solution cast technique. The formation of polymer-salt complex has been confirmed by X-ray diffraction. The DC electrical conductivity of chitosan-silver triflate electrolyte has been investigated between 303 and 423 K, using electrochemical impedance spectroscopy over the frequency range from 50 Hz to 1000 kHz. The conductivity was found to increase with increase in AgCF3SO3 concentration at room temperature. The DC conductivity obeys Arrhenius relationship up to a particular temperature and decreases at higher temperatures due to decrease in silver ions as a result of the formation of silver nanoparticles. The presence of an additional semicircular arc in the Cole-Cole plot obtained above 328 K indicates the existence of grain boundaries, which can be attributed to the silver particles. The presence of silver particles also have been proven by XRD after heating at 333, 363, and 393 K where the (1 1 1) peak of Ag is observed to increase with temperature. The silver particles were shown to be of nanosize using transmission electron microscopy (TEM).

  12. Effect of silver nanoparticles on the DC conductivity in chitosan-silver triflate polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Shujahadeen B.; Abidin, Z.H.Z. [Center for Ionics University Malaya, Physics Department, Faculty of Science, 50603 Kuala Lumpur (Malaysia); Arof, A.K., E-mail: akarof@um.edu.m [Center for Ionics University Malaya, Physics Department, Faculty of Science, 50603 Kuala Lumpur (Malaysia)

    2010-11-01

    A solid polymer electrolyte composed of chitosan and silver triflate (AgCF{sub 3}SO{sub 3}) has been prepared by the solution cast technique. The formation of polymer-salt complex has been confirmed by X-ray diffraction. The DC electrical conductivity of chitosan-silver triflate electrolyte has been investigated between 303 and 423 K, using electrochemical impedance spectroscopy over the frequency range from 50 Hz to 1000 kHz. The conductivity was found to increase with increase in AgCF{sub 3}SO{sub 3} concentration at room temperature. The DC conductivity obeys Arrhenius relationship up to a particular temperature and decreases at higher temperatures due to decrease in silver ions as a result of the formation of silver nanoparticles. The presence of an additional semicircular arc in the Cole-Cole plot obtained above 328 K indicates the existence of grain boundaries, which can be attributed to the silver particles. The presence of silver particles also have been proven by XRD after heating at 333, 363, and 393 K where the (1 1 1) peak of Ag is observed to increase with temperature. The silver particles were shown to be of nanosize using transmission electron microscopy (TEM).

  13. Effect of silver nanoparticles on the DC conductivity in chitosan-silver triflate polymer electrolyte

    Science.gov (United States)

    Aziz, Shujahadeen B.; Abidin, Z. H. Z.; Arof, A. K.

    2010-11-01

    A solid polymer electrolyte composed of chitosan and silver triflate (AgCF 3SO 3) has been prepared by the solution cast technique. The formation of polymer-salt complex has been confirmed by X-ray diffraction. The DC electrical conductivity of chitosan-silver triflate electrolyte has been investigated between 303 and 423 K, using electrochemical impedance spectroscopy over the frequency range from 50 Hz to 1000 kHz. The conductivity was found to increase with increase in AgCF 3SO 3 concentration at room temperature. The DC conductivity obeys Arrhenius relationship up to a particular temperature and decreases at higher temperatures due to decrease in silver ions as a result of the formation of silver nanoparticles. The presence of an additional semicircular arc in the Cole-Cole plot obtained above 328 K indicates the existence of grain boundaries, which can be attributed to the silver particles. The presence of silver particles also have been proven by XRD after heating at 333, 363, and 393 K where the (1 1 1) peak of Ag is observed to increase with temperature. The silver particles were shown to be of nanosize using transmission electron microscopy (TEM).

  14. Conductive Polymer Microelectrodes for on-chip measurement of transmitter release from living cells

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Matteucci, Marco

    2012-01-01

    In this paper, we present techniques to trap a group of neuronal cells (PC 12) close to band microelectrodes and quantitatively measure cellular transmitter release. Different trapping approaches were investigated including coating of electrodes by layers enhancing cell attachment and by pressure driven cell trapping inside closed chip devices. Conductive polymer microelectrodes were used to measure transmitter release using electrochemical methods such as cyclic voltammetry and constant potential amperometry. By measuring the oxidation current at a cyclic voltammogram, the concentration of released transmitter molecules could be estimated.

  15. Conducting Polymer Material Characterization Using High Frequency Planar Transmission Line Measurement

    OpenAIRE

    Young Seek Cho; Rhonda R. Franklin

    2012-01-01

    A conducting polymer, poly 3-hexylthiophene (P3HT) is characterized with the metal-insulator-semiconductor(MIS) measurement method and the high frequency planar circuit method. From the MIS measurement method, therelative dielectric constant of the P3HT film is estimated to be 4.4. For the high frequency planar circuit method, acoplanar waveguide is fabricated on the P3HT film. When applying +20 V to the CPW on P3HT film, the P3HT film isin accumulation mode and becomes lossy. The CPW on P3HT...

  16. Conducting polymers based counter electrodes for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Veerender, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Saxena, Vibha, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gusain, Abhay, E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Jha, P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Koiry, S. P., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Chauhan, A. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Aswal, D. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com; Gupta, S. K., E-mail: veeru1009@gmail.com, E-mail: veeru1009@gmail.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

    2014-04-24

    Conducting polymer films were synthesized and employed as an alternative to expensive platinum counter electrodes for dye-sensitized solar cells. poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) thin films were spin-coated and polypyrrole films were electrochemically deposited via cyclic voltammetry method on ITO substrates. The morphology of the films were imaged by SEM and AFM. These films show good catalytic activity towards triiodide reduction as compared to Pt/FTO electrodes. Finally the photovoltaic performance of DSSC fabricated using N3 dye were compared with PT/FTO, PEDOT/ITO, and e-PPy counter electrodes.

  17. Conducting polymers based counter electrodes for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Conducting polymer films were synthesized and employed as an alternative to expensive platinum counter electrodes for dye-sensitized solar cells. poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) thin films were spin-coated and polypyrrole films were electrochemically deposited via cyclic voltammetry method on ITO substrates. The morphology of the films were imaged by SEM and AFM. These films show good catalytic activity towards triiodide reduction as compared to Pt/FTO electrodes. Finally the photovoltaic performance of DSSC fabricated using N3 dye were compared with PT/FTO, PEDOT/ITO, and e-PPy counter electrodes

  18. Friendly conditions-synthesis of platinum nanoparticles supported on conducting polymer: methanol electrooxidation

    OpenAIRE

    Salavagione, Horacio Javier; Sanchis Bermúdez, Carlos; Morallón Núñez, Emilia

    2007-01-01

    An easy method to synthesize Pt nanoparticles supported on conductive polymers has been explored. The synthesis was carried out under “soft” conditions, i.e., at low temperatures and without using strong reducing agent. The optimal synthesis conditions have been established. Thus, the particles had almost monodisperse size distribution, around 2.4 nm, when the synthesis was carried out at 100 °C, and around 1.4 nm when it was done at 75 °C. Also, it has been demonstrated that the platinum loa...

  19. Conducting polymer/polyimide-clay nanocomposite coatings for corrosion protection of AA-2024 alloy

    Science.gov (United States)

    Shah, Kunal G.

    Corrosion of metals is a major problem in the aerospace and automobile industry. The current methods of corrosion protection such as chromate conversion coatings are under increased scrutiny from the Environmental Protection Agency (EPA) due to their carcinogenic nature. Intrinsically conducting polymers (ICPs) like polyaniline and polypyrrole have been considered as a potential replacement for chromate conversion coatings and have been under investigation since past decade. The goal of this study is to replace the chromate conversion coating by an environmentally friendly organic coating. Poly (N-ethyl aniline) coating was electrodeposited as the primer layer and polyimide-clay nanocomposite was solution cast as the barrier layer on AA-2024 alloy. This study will provide a better understanding of the corrosion protection mechanism of the conducting polymer coating. Various characterization techniques such as infrared spectroscopy, cyclic voltammetry and scanning electron microscopy were used to study the formation, chemical structure and morphology of the coatings. Electrodeposition parameters like monomer concentration, applied current density and the reaction time were varied in order to optimize the properties of the conducting polymer coating. The corrosion performance of the primer coating was evaluated by DC polarization studies. It was found that poly (N-ethyl aniline) reduces from emeraldine to leucoemeraldine form; reducing the rate of cathodic reaction, which reduces the rate of corrosion of AA-2024 alloy. Polyimide-clay nanocomposite coating was solution cast on the conducting polymer primer layer for enhancing the barrier and corrosion properties of the coating system. The concentration of polyimide (10--25 vol%) and clay (0.1 and 1 wt%) were varied in the coating formulation to optimize the barrier properties of topcoat. X-ray diffraction showed that the intergallery clay distance decreased from 17.2 A to 11.79 A after immidization of polyimide-clay nanocomposite coating and infrared spectroscopy suggested that there was hydrogen bonding interaction between clay and polyimide chains. DC polarization study, electrochemical impedance spectroscopy and scanning vibrating electrode technique were used to evaluate the corrosion property and model the coating degradation in corrosive medium. It was found that the corrosion property were dependent on the thickness of the barrier coat and concentration of clay in the polyimide coating. The results obtained from the above mentioned test suggest that poly (N-ethyl aniline)/polyimide-clay nanocomposite coatings system is a potential candidate to replace the traditionally used and environmentally unfriendly chromate conversion coating.

  20. Gas Sensing Properties of Single Conducting Polymer Nanowires and the Effect of Temperature

    OpenAIRE

    Dan, Yaping; Cao, Yanyan; Mallouk, Tom E.; Evoy, Stephane; Johnson, A. T. Charlie

    2008-01-01

    We measured the electronic properties and gas sensing responses of template-grown poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS)-based nanowires. The nanowires have a "striped" structure (gold-PEDOT/PSS-gold), typically 8um long (1um-6um-1um for each section, respectively) and 220 nm in diameter. Single-nanowire devices were contacted by pre-fabricated gold electrodes using dielectrophoretic assembly. A polymer conductivity of 11.5 +/- 0.7 S/cm and a con...

  1. Performance Improvement by Layout Designs of Conductive Polymer Microelectrode Based Impedimetric Biosensors

    DEFF Research Database (Denmark)

    Rosati, Giulio; Daprà, Johannes

    2014-01-01

    In this work we present a theoretical, computational, and experimental evaluation of the performance of an impedimetric biosensor based on interdigitated conductive polymer (PEDOT:TsO) microelectrodes in a microfluidic system. The influence of the geometry of the electrodes and microchannels on the electrochemical performance of the biosensor was exploited to improve the detection system. The developed model allowed us to predict the performance of the electrochemical system, and thus to optimize the geometry for electrochemical impedance spectroscopy (EIS). Finally, the optimized electrode design was validated by the detection of a clinically relevant target (ampicillin) at picomolar concentrations.

  2. A summary report on the Flat-Plate Solar Array Project Workshop on Transparent Conducting Polymers

    Science.gov (United States)

    Kachare, R.; Moacanin, J.

    1985-01-01

    The proceedings and technical discussions of a workshop on Transparent Conducting Polymers (TCP) for solar cell applications are reported. This is in support of the Device Research Task of the Flat-Flate Solar Array Project. The workshop took place on January 11 and 12, 1985, in Santa Barbara, California. Participants included university and industry researchers. The discussions focused on the electronic and optical properties of TCP, and on experimental issues and problems that should be addressed for high-efficiency solar cell application.

  3. Conductivity and Activation Energy in Polymers Synthesized by Plasmas of Thiophene

    Scientific Electronic Library Online (English)

    Ma. Guadalupe, Olayo; Guillermo J., Cruz; Salvador, López; Juan, Morales; Roberto, Olayo.

    2010-03-01

    Full Text Available En este trabajo se estudia la síntesis por plasmas resistivos a radiofrecuencia de politiofeno, su conductividad eléctrica, energía de activación y morfología. Las continuas colisiones de partículas en el plasma inducen la polimerización del tiofeno pero también rompen algunos anillos del monómero p [...] roduciendo polímeros complejos con anillos de tiofeno y segmentos de hidrocarburos alifáticos. Estas reacciones químicas multidireccionales son más marcadas en tiempos de reacción largos donde la morfología de las películas evoluciona de superficies lisas, a bajos tiempos de reacción, hasta la formación de partículas esféricas con diámetros de 300 a 1000 nm. Entre ambas morfologías, algunas burbujas se forman sobre la superficie. La conductividad intrínseca de los politiofenos sintetizados de esta manera varía en el intervalo de 10-10 a 10-8 S/m, con conductividad sensible a la humedad de los polímeros, la cual produce variaciones de hasta 5 órdenes de magnitud. La energía de activación relacionada con la conductividad intrínseca se calculó entre 0.56 y 1.41 eV, incrementándose con el tiempo de reacción. Abstract in english The electric conductivity, activation energy and morphology of polythiophene synthesized by radiofrequency resistive plasmas are studied in this work. The continuous collisions of particles in the plasma induce the polymerization of thiophene but also break some of the monomer molecules producing co [...] mplex polymers with thiophene rings and aliphatic hydrocarbon segments. These multidirectional chemical reactions are more marked at longer reaction times in which the morphology of the polymers evolved from smooth surfaces, at low exposure time, to spherical particles with diameter in the 300-1000 nm interval. Between both morphologies, some bubbles are formed on the surface. The intrinsic conductivity of plasma polymers of thiophene synthesized in this way varied in the range of 10-10 to 10-8 S/m; however, the conductivity resulted very sensitive to the water content in the polymers, which produced variations of up to 5 magnitude orders. The activation energy of the intrinsic conductivity was between 0.56 and 1.41 eV, increasing with the reaction time.

  4. Impedance Study of Drinking Water and Tastants Using Conducting Polymer and Metal Electrodes

    OpenAIRE

    Pawan Kapur; Mopsy Dhiman,; Ganguli; Madan Lal Singla

    2012-01-01

    In this study the sensing capabilities of a combination of metals and conducting polymer electrodes for drinking water and dissolved tastants using an AC-impedance mode in frequency range 102 to 105 Hz at 0.1 V potential has been carried out. Classification of seven different bottled and municipal drinking water samples along with various tastants dissolved in DI water(DI water) for KCl (5mM) (salty), HCl (5 mM) (sour) quinine (0.1 mM) (bitter), sucrose (5 mM) (sweet), black tea liquor, blac...

  5. Ferroelectric polymer-gated graphene memory with high speed conductivity modulation

    International Nuclear Information System (INIS)

    The feasibility of a high speed ferroelectric graphene memory device using a ferroelectric polymer (PVDF–TrFE)/graphene stack has been demonstrated. The conductivity of this metal–ferroelectric–graphene (MFG) device could be modulated up to 775% with a very fast programming speed down to 10 ns. Also, programmed states were maintained up to 1000 s with endurance over 1000 cycles. In addition to demonstrating a single memory device, the array-level integration and cell write/read functionality of a 4 × 4 MFG array adopting a graphene bit line has also been confirmed to show the feasibility of MFG memory. (paper)

  6. Light-Controlled Conductance Switching in Azobenzene-Containing MWCNT-Polymer Nanocomposites.

    Science.gov (United States)

    Basuki, Sri Wahyuni; Schneider, Viktor; Strunskus, Thomas; Elbahri, Mady; Faupel, Franz

    2015-06-01

    We report on reversible light-controlled conductance switching in devices consisting of multiwalled carbon nanotube (MWCNT)-polymer nanocomposites blended with azobenzene molecules and photoisomerization of the latter. Both the azobenzene molecules and MWCNT, which are functionalized with carboxyl groups (MWCNT-COOH), are embedded independently in a poly(methyl methacrylate) matrix, and thin films are prepared by using a simple spin-coating technique. We demonstrate the feasibility of the present concept with a photocurrent switching amplitude of almost 10%. PMID:25961784

  7. Electrical conductivity and Raman imaging of double wall carbon nanotubes in a polymer matrix

    OpenAIRE

    Tishkova, Victoria; Raynal, Pierre Ivan; Puech, Pascal; Lonjon, Antoine; Le Fournier, Marion; Demont, Philippe; Flahaut, Emmanuel; Bacsa, Wolfgang

    2011-01-01

    Raman spectroscopy is used to access the dispersion state of DWNTs in a PEEK polymer matrix. The interaction of the outer tube with the matrix can be determined from the line shape of the Raman G band. This allows us to distinguish regions where the nanotubes are well dispersed and regions where the nanotubes are agglomerated. The percolation threshold of the electrical conductivity of the double wall carbon nanotubes (DWNTs)/PEEK nanocomposites is found to be at 0.2-0.3 wt.%. We find a maxim...

  8. Nanocrystal skins with exciton funneling for photosensing.

    Science.gov (United States)

    Akhavan, Shahab; Cihan, Ahmet Fatih; Bozok, Berkay; Demir, Hilmi Volkan

    2014-06-25

    Highly photosensitive nanocrystal (NC) skins based on exciton funneling are proposed and demonstrated using a graded bandgap profile across which no external bias is applied in operation for light-sensing. Four types of gradient NC skin devices (GNS) made of NC monolayers of distinct sizes with photovoltage readout are fabricated and comparatively studied. In all structures, polyelectrolyte polymers separating CdTe NC monolayers set the interparticle distances between the monolayers of ligand-free NCs to <1 nm. In this photosensitive GNS platform, excitons funnel along the gradually decreasing bandgap gradient of cascaded NC monolayers, and are finally captured by the NC monolayer with the smallest bandgap interfacing the metal electrode. Time-resolved measurements of the cascaded NC skins are conducted at the donor and acceptor wavelengths, and the exciton transfer process is confirmed in these active structures. These findings are expected to enable large-area GNS-based photosensing with highly efficient full-spectrum conversion. PMID:24599603

  9. Ionic conduction and electrochemical properties of new poly(acrylonitrile-itaconate)-based gel polymer electrolytes

    Science.gov (United States)

    Kim, Y. W.; Gong, M. S.; Choi, B. K.

    A new copolymer polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate (abbreviated as PANI) was synthesized in the hope of getting a polymer host having a better ability of trapping organic solvent to overcome the drawbacks of polyacrylonitrile (PAN) system gel polymer electrolytes. Blend of PAN and PANI was complexed with organic solvents, ethylene carbonate (EC) and ?-butyrolactone (BL), and LiClO 4 salt. The highest room temperature conductivity of 1.9×10 -3 S cm -1 was found for a film of 25PAN-10PANI-50EC/BL-15LiClO 4. The PANI was found to effectively trap organic solvents and, therefore, greatly enhance the miscibility of polymer host and solvents, possibly due to ion chelating ability of itaconate unit. The PAN-PANI blend gel-electrolyte, as compared with pristine PAN-based electrolyte, had better electrochemical stability and was more stable toward lithium electrode, though it exhibited slightly less mechanical rigidity caused by amorphization of the PAN matrix.

  10. Electrical Conductivity Studies on Individual Conjugated Polymer Nanowires: Two-Probe and Four-Probe Results

    Directory of Open Access Journals (Sweden)

    Duvail JeanLuc

    2009-01-01

    Full Text Available Abstract Two- and four-probe electrical measurements on individual conjugated polymer nanowires with different diameters ranging from 20 to 190 nm have been performed to study their conductivity and nanocontact resistance. The two-probe results reveal that all the measured polymer nanowires with different diameters are semiconducting. However, the four-probe results show that the measured polymer nanowires with diameters of 190, 95–100, 35–40 and 20–25 nm are lying in the insulating, critical, metallic and insulting regimes of metal–insulator transition, respectively. The 35–40 nm nanowire displays a metal–insulator transition at around 35 K. In addition, it was found that the nanocontact resistance is in the magnitude of 104? at room temperature, which is comparable to the intrinsic resistance of the nanowires. These results demonstrate that four-probe electrical measurement is necessary to explore the intrinsic electronic transport properties of isolated nanowires, especially in the case of metallic nanowires, because the metallic nature of the measured nanowires may be coved by the nanocontact resistance that cannot be excluded by a two-probe technique.

  11. Visible-light active conducting polymer nanostructures with superior photocatalytic activity.

    Science.gov (United States)

    Ghosh, Srabanti; Kouame, Natalie Amoin; Remita, Samy; Ramos, Laurence; Goubard, Fabrice; Aubert, Pierre-Henri; Dazzi, Alexandre; Deniset-Besseau, Ariane; Remita, Hynd

    2015-01-01

    The development of visible-light responsive photocatalysts would permit more efficient use of solar energy, and thus would bring sustainable solutions to many environmental issues. Conductive polymers appear as a new class of very active photocatalysts under visible light. Among them poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most promising conjugated polymer with a wide range of applications. PEDOT nanostructures synthesized in soft templates via chemical oxidative polymerization demonstrate unprecedented photocatalytic activities for water treatment without the assistance of sacrificial reagents or noble metal co-catalysts and turn out to be better than TiO2 as benchmark catalyst. The PEDOT nanostructures exhibit a narrow band gap (E?=?1.69?eV) and are characterized by excellent ability to absorb light in visible and near infrared region. The novel PEDOT-based photocatalysts are very stable with cycling and can be reused without appreciable loss of activity. Interestingly, hollow micrometric vesicular structures of PEDOT are not effective photocatalysts as compared to nanometric spindles suggesting size and shape dependent photocatalytic properties. The visible-light active photocatalytic properties of the polymer nanostructures present promising applications in solar light harvesting and broader fields. PMID:26657168

  12. Development of ammonia sensors by using conductive polymer/hydroxyapatite composite materials.

    Science.gov (United States)

    Huixia, Li; Yong, Liu; Lanlan, Luo; Yanni, Tan; Qing, Zhang; Kun, Li

    2016-02-01

    In order to improve the gas sensing properties, hydroxyapatite (HAp)-based composites were prepared by mixing with different contents of conductive polymers: polypyrrole (PPy) and polyaniline (PAni). The compositions, microstructures and phase constitutions of polymer/HAp composites were characterized, and the sensing properties were studied using a chemical gas sensing (CGS-8) system. The results showed that, compared to pure HAp, the sensitivities of the composites to ammonia were improved significantly. 5%PPy/HAp and 20%PAni/HAp composites exhibited the best sensitivities to ammonia, and the sensitivities at 500ppm were 86.72% and 86.18%, respectively. Besides, the sensitivity of 5%PPy/HAp at 1000ppm was up to 90.7%. Compared to pure PPy and PAni, the response and the recovery time of 5%PPy/HAp and 20%PAni/HAp at 200ppm were shortened several times, and they were 24s/245s and 15s/54s, respectively. In addition, the composites showed a very high selectivity to ammonia. The mechanism for the enhancement of the sensitivity to ammonia was also discussed. The polymer/HAp composites are very promising in applications of ammonia sensors. PMID:26652394

  13. Conductive polymer nanotube patch for fast and controlled in vivo transdermal drug delivery

    Science.gov (United States)

    Nguyen, Thao M.

    Transdermal drug delivery has created new applications for existing therapies and offered an alternative to the traditional oral route where drugs can prematurely metabolize in the liver causing adverse side effects. Opening the transdermal delivery route to large hydrophilic drugs is one of the greatest challenges due to the hydrophobicity of the skin. However, the ability to deliver hydrophilic drugs using a transdermal patch would provide a solution to problems of other delivery methods for hydrophilic drugs. The switching of conductive polymers (CP) between redox states cause simultaneous changes in the polymer charge, conductivity, and volume—properties that can all be exploited in the biomedical field of controlled drug delivery. Using the template synthesis method, poly(3,4-ethylenedioxythiophene (PEDOT) nanotubes were synthesized electrochemically and a transdermal drug delivery patch was successfully designed and developed. In vitro and in vivo uptake and release of hydrophilic drugs were investigated. The relationship between the strength of the applied potential and rate of drug release were also investigated. Results revealed that the strength of the applied potential is proportional to the rate of drug release; therefore one can control the rate of drug release by controlling the applied potential. The in vitro studies focused on the kinetics of the drug delivery system. It was determined that the drug released mainly followed zero-order kinetics. In addition, it was determined that applying a releasing potential to the transdermal drug delivery system lead to a higher release rate constant (up to 7 times greater) over an extended period of time (˜24h). In addition, over 24 hours, an average of 80% more model drug molecules were released with an applied potential than without. The in vivo study showed that the drug delivery system was capable of delivering model hydrophilic drugs molecules through the dermis layer of the skin within 30 minutes, while the control showed no visible drugs at the same depth. Most importantly, it was determined that the delivery of drugs into the blood stream was stable within 20 minutes. The functionalization of CP was also studied in order to enhance the properties and drug loading capabilities of the polymers. The co-polymerization of poly(3,4-(2-methylene)propylenedioxythiophene) (PMProDot) with polystyrene (PS) and polyvinylcarbazole (PVK) through the highly reactive methylene group was achieved. The modified PMProDot nanotubes demonstrated response times that were two times faster than without modification. The modification of PEDOT nanotubes with polydopamine, a biocompatible polymer, was also investigated and achieved. In depth characterization of functionalized CP demonstrate the ability to fine tune the properties of the polymer in order to achieve the required therapeutic drug release profile.

  14. Montmorillonite as a Conductivity Enhancer in (PEO)9LiCF3SO3 Polymer Electrolyte

    Science.gov (United States)

    Manoratne, C. H.; Rajapakse, R. M. G.; Dissanayake, M. A. K. L.; Bandara, W. M. A. T.; Tennakoon, D. T. B.

    2006-06-01

    The solid polymer electrolyte systems, based on poly(ethylene oxide) (PEO) and lithium ions have attracted much attentions as a potential electrolyte medium in secondary energy sources and electrochromic devises. They show a characteristic property of an enhanced ionic conductivity when a plastizier is added. In this research work, PEO and lithium triflate have been taken as the electrolyte medium and an attempt was paid to improve the ionic conductivity of (PEO)9LiCF3SO3 polymer electrolyte system by choosing montmorillonite (MMT) as the plastisizer. The ionic conductivity, thermal transitions, crystallinity, and bonding of the complex system of (PEO)9LiCF3SO3 + x wt.% MMT (x = 0, 3, 4, 5, 6, 10, 15, 20) were systematically characterized by ac-impedance spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD) spectroscopy and fourier transformed infrared (FTIR) spectroscopy, respectively. The ac-impedance data reveal that the ionic conductivity of (PEO)9LiCF3SO3 system is changed with the concentration of MMT, maximum conductivity of 4.14857 × 10-7 S cm-1 at room temperature was observed for the system of (PEO)9LiCF3SO3 + 5 wt.% MMT. However, the ionic conductivity of the above system was increased with the increase of temperature, and the highest conductivity of 2.63 × 10-4 S cm-1 was observed at 80°C. The DSC and XRD data clearly show that the crystalline nature of PEO is reduced when MMT is added. The glass transition temperature (-46.37°C) and melting temperature (53.72°C) of the above system is reduced compared to those of other systems. This supports to the conductivity enhancement in an amorphous environment. The FTIR spectra obtained for MMT, PEO, (PEO)9LiCF3SO3, and (PEO)9LiCF3SO3 + 5 wt.% MMT clearly indicative that the interactions take place between these constituents, as the intensities of typical stretching vibrational modes of 916 cm-1 ? (Al-O-H), 1040 cm-1 ? (Si-O) and 3300-3700 cm-1 ? (O-H) in MMT, and the vibrational modes of CH2 rocking at 948 and 840 cm-1 and C-O stretching at 1149 and 1090 cm-1 in PEO are shifted. The change of symmetric bending mode of CF3 [?s (CF3)] at 752 cm-1 in lithium triflate has altogether supported the bonding characteristics in the electrolyte system and the corresponding conductivity enhancements.

  15. Lattice thermal conductivity diminution and high thermoelectric power factor retention in nanoporous macroassemblies of sulfur-doped bismuth telluride nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanliang; Mehta, Rutvik J.; Belley, Matthew; Han, Liang; Ramanath, Ganpati; Borca-Tasciuc, Theodorian

    2012-01-01

    We report ultralow lattice thermal conductivity in the 0.3 ???L???0.6?W m?¹ K?¹ range in nanoporous bulk bismuth telluride pellets obtained by sintering chemically synthesized nanostructures, together with single-crystal-like electron mobilities and Seebeck coefficients at comparable charge carrier concentrations. The observed ?L is up to 35% lower than classical effective medium predictions, and can be quantitatively explained by increased phonon scattering at nanopores and nanograins. Our findings are germane to tailoring nanoporous thermoelectric materials for efficient solid-state refrigeration, thermal energy harvesting, and thermal management applications.

  16. Electrochemomechanical Behaviour of Bilayer and Trilayer Films with PEDOT and PPY Conducting Polymers.

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.

    2008-01-01

    A detailed study on bilayer and trilayer films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers is reported. Both polymers are doped with dodecyl benzenesulfonate (DBS) anions. These multi layer films were prepared electrochemically so that the PEDOT layer is very thin compared to that of the PPy layer, and characterized using cyclic voltammetry, optical absorption spectroscopy and electrochemical quartz crystal microbalance (EQCM) techniques. Actuators of bilayer and trilayer free standing films were characterized electromechanically under a constant load of 1.5 g. The cyclic voltammograms as well as the UV-visible spectra of PEDOT and PPy are very different, pointing towards the possibility of being able to separate the two layers experimentally – even when combined in a single film. Bilayer results show combined characteristics of each individual polymer. In trilayer films, the reduction of inner and outer PPy layers takes place at two different potentials. The oxidation occurs at one potential only. The separation between the two reduction peaks depends on the thickness of PEDOT layer, the scan rate and the concentration of cycling electrolyte. This separation becomes smaller with the number of cycles, indicating the enhancement of ion diffusion through the PEDOT layer. Electrochemomechanical measurements show that the strain generated in the polymer significantly decreases with increasing scan rate. Rapid increment in strain and cycling charge is observed during the first few cycles. Bilayer film shows a significant increase in the strain measured at higher scan rate (> 100 mV s-1). The force generation between reduced and oxidized states is much higher for trilayer films and higher for bilayer films than that in a single layer of PPy. These differences are not linked to the Young’s modulus of these films. The addition of a thin PEDOT does not change the Young’s modulus, but changes the force generation significantly.

  17. Hybrid nanocomposites based on conducting polymer and silicon nanowires for photovoltaic application

    Energy Technology Data Exchange (ETDEWEB)

    Chehata, Nadia, E-mail: nadiachehata2@gmail.com [Equipe Dispositifs Electroniques Organiques et Photovoltaïque Moléculaire, Laboratoire de la Matière Condensée et des Nanosciences, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Ltaief, Adnen [Equipe Dispositifs Electroniques Organiques et Photovoltaïque Moléculaire, Laboratoire de la Matière Condensée et des Nanosciences, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Ilahi, Bouraoui [Laboratoire de Micro-optoélectronique et Nanostructures, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Salem, Bassem [Laboratoire des Technologies de la Microélectronique (LTM), UMR 5129 CNRS - UJF, CEA Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Bouazizi, Abdelaziz [Equipe Dispositifs Electroniques Organiques et Photovoltaïque Moléculaire, Laboratoire de la Matière Condensée et des Nanosciences, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Maaref, Hassen [Laboratoire de Micro-optoélectronique et Nanostructures, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Baron, Thierry [Laboratoire des Technologies de la Microélectronique (LTM), UMR 5129 CNRS - UJF, CEA Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); and others

    2014-12-15

    Hybrid nanocomposites based on a nanoscale combination of organic and inorganic semiconductors are a promising way to enhance the performance of solar cells through a higher aspect ratio of the interface and the good processability of polymers. Nanocomposites are based on a heterojunction network between poly (2-methoxy-5-(2-ethyhexyl-oxy)-p-phenylenevinylene) (MEH-PPV) as an organic electron donor and silicon nanowires (SiNWs) as an inorganic electron acceptor. Nanowires (NWs) seem to be a promising material for this purpose, as they provide a large surface area for contact with the polymer and a designated conducting pathway whilst their volume is low. In this paper, silicon nanowires are introduced by mixing them into the polymer matrix. Hybrid nanocomposites films were deposited onto ITO substrate by spin coating method. Optical properties and photocurrent response were investigated. Charge transfer between the polymer and SiNWs has been demonstrated through photoluminescence measurements. The photocurrent density of ITO/MEH-PPV:SiNWs/Al structures have been obtained by J–V characteristics. The J{sub sc} value is about 0.39 µA/cm{sup 2}. - Highlights: • SiNWs synthesis by Vapor–Liquid–Solid (VLS) mechanism. • SiNWs contribution to absorption spectra enhancement of MEH-PPV:SiNWs nanocomposites. • Decrease of PL intensity of MEH-PPV by addition of SiNWs. • Charge transfer process was taken place. • ITO/MEH-PPV:SiNWs/Al structure shows a photovoltaic effect, with a FF of 0.32.

  18. A novel conductive-polymer-based integration process for high-performance flip-chip packages

    Science.gov (United States)

    Lohokare, Saurabh

    Conductive polymers have recently attracted considerable attention for low-temperature fabrication of lead-free, reworkable, and flexible flip-chip interconnects. Using these materials, I demonstrate in this thesis a process that enables low-cost and high-resolution flip-chip interconnects using conventional micro-fabrication techniques. This fabrication process offers improved performance as compared to conventional flip-chip techniques, such as screen-printing, and allows for definition of interconnects with excellent surface uniformity and control over the bump profile. In order to demonstrate the utility and wide applicability of this process, several test implementations that serve as case studies were investigated. Specifically, novel InGaAsSb avalanche photodiodes (APDs), operating around lambda = 2m and targeted for free-space communication and biomedical spectroscopy applications, were fabricated and flip-chip-integrated to test the static electrical characteristics of the polymer bumps. Additionally, the dynamic electrical performance characteristics of the polymer bumps were studied by using AlGaAsSb/AlGaSb p-i-n photodetectors as a case study. The fabrication of these photodetectors, operating around lambda = 1.55mum and targeted for optical communication applications, was accomplished using a customized inductively coupled plasma (ICP) etch process that resulted in a low dark current and excellent speed (3dB bandwidth of 10GHz) and, responsivity (60% external quantum efficiency) characteristics. Furthermore, flip-chip integration was used to demonstrate a three-dimensional, point-to-point micro-optical interconnect, which was 2.33mm-long in a system 15.27mm3 in volume. Lastly, high-speed parallel optical interconnects were demonstrated using polymer-flip-chip-integrated 10GHz vertical-cavity surface-emitting laser (VCSEL) and DOEs. Such interconnects offer the ability to alleviate the communication bottleneck that is projected to occur in future, high-performance computing systems.

  19. Impact of polymer electrolyte membrane fuel cell microporous layer nano-scale features on thermal conductance

    Science.gov (United States)

    Botelho, S. J.; Bazylak, A.

    2015-04-01

    In this study, the microporous layer (MPL) of the polymer electrolyte membrane (PEM) fuel cell was analysed at the nano-scale. Atomic force microscopy (AFM) was utilized to image the top layer of MPL particles, and a curve fitting algorithm was used to determine the particle size and filling radius distributions for SGL-10BB and SGL-10BC. The particles in SGL-10BC (approximately 60 nm in diameter) have been found to be larger than those in SGL-10BB (approximately 40 nm in diameter), highlighting structural variability between the two materials. The impact of the MPL particle interactions on the effective thermal conductivity of the bulk MPL was analysed using a discretization of the Fourier equation with the Gauss-Seidel iterative method. It was found that the particle spacing and filling radius dominates the effective thermal conductivity, a result which provides valuable insight for future MPL design.

  20. Surface-conductive polymer composites based on (BEDT-TTF)2Cu(SCN)2

    International Nuclear Information System (INIS)

    Methods of preparation and studies of the properties of the first polymer composites using (BEDT-TTF)2Cu(SCN)2 (BEDT-TTF=bis(ethylenedithio)tetrathiaf ulvalene) as a conductive phase are reported. It is shown that a network of a conductive (BEDT-TTF)2Cu(SCN)2 salt can be obtained. However, besides superconducting ?-(BEDT-TTF)2Cu(SCN)2 at least two other salts which comprise Cu(SCN)2- are known: ?-phase and (BEDT-TTF)Cu2(SCN)3. Scanning electron microscopy (SEM) micrographs and X-ray diffractograms have shown that, although by chemical oxidation the ?-phase is usually obtained, in the composite films the additive crystallization leads mostly to ?-(BEDT-TTF)2Cu(SCN)2. (orig.)