Helical Polyacetylene Synthesized with a Chiral Nematic Reaction Field

Akagi, Kazuo; Piao, Guangzhe; Kaneko, Shunta; Sakamaki, K.; Shirakawa, Hideki; Kyotani, Mutsumasa

doi:10.1126/science.282.5394.1683

Cited by 405 publications

(206 citation statements)

References 11 publications

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“…[26][27][28] There is a new, advanced form of PA -helical PA (hel PA), synthesized using a chiral nematic liquid crystal as the solvent for the Ziegler-Natta catalyst. [12] Hel PA can be obtained with either R-(counterclockwise) or S-(clockwise) type helicity. X-ray diffraction patterns of both R-and S-type hel PA show a broad reflection, indicating that the films are polycrystalline, corresponding to a spacing of 3.68 A, characteristic of trans-PA. [29] A single fiber has a cross-section that is typically 40-65 nm wide and 130-300 nm high.…”

Section: Advances In the Synthesis Of Polymer Nanofibers And Nanotubesmentioning

confidence: 99%

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Polymer Nanofibers and Nanotubes: Charge Transport and Device Applications

2005

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A critical analysis of recent advances in synthesis and electrical characterization of nanofibers and nanotubes made of different conjugated polymers is presented. The applicability of various theoretical models is considered in order to explain results on transport in conducting polymer nanofibers and nanotubes. The relationship between these results and the one-dimensional (1D) nature of the conjugated polymers is discussed in light of theories for tunneling in 1D conductors (e.g. Luttinger liquid, Wigner crystal). The prospects for nanoelectronic applications of polymer fibers and tubes as wires, nanoscale field-effect transistors (nanoFETs), and in other applications are analyzed.

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Section: Advances In the Synthesis Of Polymer Nanofibers And Nanotubesmentioning

confidence: 99%

“…The most commonly used techniques are template synthesis, [9][10][11] chiral reaction, [12] selfassembly, [13] interfacial polymerization, [14,15] and electrospinning. [16] The template synthesis method is an effective route to synthesize nanofibrils and nanotubes of various polymers.…”

Section: Advances In the Synthesis Of Polymer Nanofibers And Nanotubesmentioning

confidence: 99%

Polymer Nanofibers and Nanotubes: Charge Transport and Device Applications

2005

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“…(a) We have studied helical PA (hel PA) nanofibers synthesized using chiral nematic liquid crystal as a solvent of Ziegler-Natta catalyst following the procedure presented elsewhere [17]. Hel PA has polycrystalline structure [18] and can be made with either R-(counterclockwise) or S-(clockwise) type helicity.…”

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confidence: 99%

Coulomb-blockade transport in quasi-one-dimensional polymer nanofibers

et al. 2005

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We report the low temperature current-voltage (I-V) characteristics studies in quasi one-dimensional conducting polymer nanofibers. We find a threshold voltage V t below which little current flows at temperatures below 30 -40 K. For V > V t current scales as (V/V t -1) ζ , where ζ ~ 1.8 -2.1 at high biases. Differential conductance oscillations are observed whose magnitude increases as temperature decreases below 10 K. We attributed the observed low temperature I-V behavior to Coulomb blockade effects with a crossover to Luttinger liquid-like behavior at high temperature. We demonstrate that at low temperatures such a doped conjugated polymer fiber can be considered as an array of small conducting regions separated by nanoscale barriers, where the Coulomb blockade tunneling is the dominant transport mechanism.PACS numbers: 71.30.+h, 72.20.Ee, 72.80.Le Complex structures built of nanosize conducting objects provide model systems for investigation of transport phenomena on the mesoscopic scale, where quantum confinement and Coulomb charging play an important role [1]. Electronic transport through an array of metallic nanocrystals separated by nanobarriers is determined by the interplay between single-electron charging of an individual conducting region and tunneling between adjacent islands. In such systems both the tunneling resistance between neighboring regions is large, R T >> h/e 2 and the charging energy E C = e 2 /2C of an excess electron on a site is larger than k B T (C is the capacitance of the region). In the presence of both charge and structural disorder this interplay leads to highly nonOhmic current-voltage (I-V) characteristics. Coulomb blockade theory predicts that at low temperatures, there is no current below a specific threshold voltage, V t , while above V t the current follows a power law:with ζ ~ 1 in one dimensional (1D) and 5/3 or 2 in twodimensional (2D) systems [2]. V t depends on the nanocrystal number, the capacitance of the conducting regions and the capacitance between the each region and the back gate. Such a behavior with scaling exponents between 1 and 2.3 has been found, for example, in narrow chains of carbon nanoparticles [3], and in 100 nm wide multilayer of gold particles which exhibited ζ ~ 1.6 [4]. Coulomb-blockade effects have also been observed in multiwalled carbon nanotubes [5], organic thin-film transistors based on highly ordered molecular materials [6] as well as in single-molecular transistor structures [7]. It is evident that the nature of the individual regions: metallic, semiconducting, quantum dots -is irrelevant for this phenomenon to be observed [8]. In view of these results the question arises whether Coulomb-blockade effects can also be observed in such inherent quasi-1D systems as conducting polymer nanofibers. In this connection polyacetylene (PA) nanofibers are of particular interest as the model system for nanotransport studies because of the simple chemical structure, well defined polycrystallinity [9], and good ability for doping [10][11][12]. It is...

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“…Conjugated polymers can be synthesised in a precisely controlled way to form many different structures down to the molecular scale. The most commonly used techniques are template synthesis [10], chiral reactions [11], self-assembly [12], interfacial polymerisation [13], and electrospinning [14]. Use of nanostructured polyaniline (PANi), in the form of nanowires, nanotubes, nanofibres, or nanorods, could greatly improve the sensitivity, owing to the higher exposed surface area, relative to their bulk counterparts [15].…”

Section: Introductionmentioning

confidence: 99%

Concentration-dependent growth and morphology of doped polyaniline nanowires

Nair

Rajeswari

Natarajan

et al. 2013

Journal of Experimental Nanoscience

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Polyaniline nanowires with entangled network structures were synthesised through an electropolymerisation route using a step galvanostatic method on titanium substrate. The morphology of the synthesised polyaniline was investigated by scanning electron microscopy and transmission electron microscopy. The dependence of morphology on the concentration and duration of synthesis has also been studied. Structural characterisation has been done by UV-VIS spectroscopy and Fourier transform infrared spectroscopy. The concentration of the monomer and the duration of synthesis affect the morphology as well as the amount of nanowires deposited.

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Helical Polyacetylene Synthesized with a Chiral Nematic Reaction Field

Cited by 405 publications

References 11 publications

Polymer Nanofibers and Nanotubes: Charge Transport and Device Applications

Polymer Nanofibers and Nanotubes: Charge Transport and Device Applications

Coulomb-blockade transport in quasi-one-dimensional polymer nanofibers

Concentration-dependent growth and morphology of doped polyaniline nanowires

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