60 resultados para semi conducting polymers, electroluminescence, photovoltaics


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The synthesis, characterisation and polymerisation studies of a homologous series of α,ω-bis(pyrrolyl)alkanes are described. These α,ω-bis(pyrrolyl)alkanes were produced using Friedel–Crafts acylation followed by reduction of the carbonyl group using Red-Al®. Chemical polymerisation of the resultant dimers using FeCl3 produced poly(α,ω-bis(pyrrolyl)alkane) films, which were characterised by SEM, FTIR and tested for conductivity.

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Cross-linked poly(α,ω-bis(3-pyrrolyl)alkanes) were directly applied to woven wool substrates by either chemical, vapour or mist polymerization methods. Choice of dopant could greatly improve the surface resistance. The optimum coating on textiles with the lowest surface resistance, highest colour-fastness and stability was achieved using a mist polymerization method with 1,8-bis(pyrrolyl)octane, iron(III) chloride (FeCl3) as the oxidant and p-toluene sulfonic acid sodium salt (pTSA) as the dopant.

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An optimized synthetic method for the production of fluorescent conductive wool using pyrene, rhodamine B and fluorescein is reported. The application of fluorescent conductive polymers to wool was studied using solution and mist polymerization techniques. The effects of incorporating fluorescent dopants into the polymerization solution as well as the encapsulation of fluorescent dyes in a polypyrrole (PPy) micelle were also investigated. It was determined on the basis of both conductivity and fluorescence measurements that the encapsulation of dyes in PPy onto the surface of textiles gave the best results.

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An abrasion-resistant, electrically conductive material comprising a natural fibre-containing substrate and an electrically conductive conjugated polymer coating thereon is disclosed. A process for preparing an abrasion-resistant, electrically conductive material is also disclosed. The process comprises providing at least one monomer capable of forming an electrically conductive conjugated polymer, and a suitable substrate having a substrate surface, subjecting the substrate surface to a surface treatment step to improve abrasion resistance, and exposing the substrate surface to a vapour of the monomer to form an electrically conductive conjugated polymer coating thereon.

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This research first clarified a possible chemical reaction between a dispersing dye and the conducting polymer polypyrrole. Then, the effect of acidic dyes as dopants on the colours, conductivity and thermal stability of polypyrrole were measured. Finally, the polypyrrole nanoparticles were prepared by a microemulsion polymerisation technique.

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Electrochemical synthesis of inherently conducting polymers such as polypyrrole is traditionally performed in a molecular solvent/electrolyte system such acetonitrile/lithium perchlorate. We report the use of ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide and N,N-butylmethylpyrrolidinium bis(trifluoromethanesulfonyl) amide, both as the growth medium and as an electrolyte for the electrochemical cycling of polypyrrole films. Use of the ionic liquid as the growth medium results in significantly altered film morphologies and improved electrochemical activities.

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The commonly held perception that high conductivity in conducting polymers is linked to a high level of π-stacking order in the material is shown here to be of lesser importance in highly conducting poly(3,4-ethylenedioxythiophene) (PEDT), which has been prepared by chemical vapour phase polymerisation. Despite the fact that there is a highly energetic phase transition about 130 °C (110 J/g), and that this transition corresponds to a loss of the long-range π-stacking as observed in grazing angle XRD, the conductivity remains unchanged beyond the transition and only decreases by a factor of two when heating to above 200 °C. The XRD data suggest that order in two dimension remains above the phase transition measured by DSC and this order is sufficient to maintain a high level of electronic conductivity. Furthermore, as the ligand on the iron salt used in the synthesis is varied, the conductivity of the PEDT varies over two orders of magnitude. These phenomena cannot be explained by different degree of doping or crystallinity and it is proposed that the iron salt has an ordering effect during the vapour phase polymerisation.

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Au-doped polyacrylonitrile–polyaniline core–shell nanofibers are fabricated via electrospinning and subsequent gas-phase polymerization, providing a very high field-effect mobility of up to 11.6 cm2 V−1 s−1. This method is also suitable for other conducting polymers and may eventually lead to a new and simplified fabrication of high-performance polymer organic field-effect transistors.