Conducting Polymer Nanostructures Research Articles

Conducting Polymer Nanostructures and Nanocomposites with Carbon Nanotubes: Hierarchical Assembly by Molecular Electrochemistry, Growth Aspects and Property Characterization.

Conducting (or π-conjugated) polymers are promising materials for preparing supramolecular nano-structures and nanocomposites. We report controlled nanostructure syntheses of polypyrrole (PPy) and poylaniline (PANi) via electropolymerization (i.e., in-situ electrochemical anodic oxidation). The density, shape, caliber and thickness of self-assembled PPy micro-containers are regulated by electrochemical potential window for H2 bubbles and number of cyclic voltammetric (potentiodynamic) scans. Likewise, we employed amperometry, chronopotentiometry and potentiodynamic modes using hydrochloric acid as oxidizing agent to prepare PANi nanoparticles and nanotubules. We present our findings from the viewpoint of molecular electrochemistry with growth kinetic aspects yielding mechanistic details (initially forming dimers and oligomers as nucleating agents followed by polymer growth). Also targeted is forming nanocomposites with functionalized single- and multi-walled carbon nanotubes (FSWCNTs and FMWCNTs) as reinforced agent to optimize structural and functional properties. All of these novel nanomaterials are characterized using a range of complementary techniques to establish microscopic structure-property-function relationship.

Nanostructured conducting polymers for energy applications: towards a sustainable platform.

Recently, there has been tremendous progress in the field of nanodimensional conducting polymers with the objective of tuning the intrinsic properties of the polymer and the potential to be efficient, biocompatible, inexpensive, and solution processable. Compared with bulk conducting polymers, conducting polymer nanostructures possess a high electrical conductivity, large surface area, short path length for ion transport and superior electrochemical activity which make them suitable for energy storage and conversion applications. The current status of polymer nanostructure fabrication and characterization is reviewed in detail. The present review includes syntheses, a deeper understanding of the principles underlying the electronic behavior of size and shape tunable polymer nanostructures, characterization tools and analysis of composites. Finally, a detailed discussion of their effectiveness and perspectives in energy storage and solar light harvesting is presented. In brief, a broad overview on the synthesis and possible applications of conducting polymer nanostructures in energy domains such as fuel cells, photocatalysis, supercapacitors and rechargeable batteries is described.

Electrically conducting polymer nanostructures confined in anodized aluminum oxide templates (AAO)

Financial support from the Spanish ‘Ministerio de Economia y Competitividad’ under projects MAT2011-24797 and MAT2014-53437-C2-1 is acknowledged. The authors thank D. Gomez for SEM experiments and I. Munoz for Raman spectra. Authors thank Miguel Angel Lopez Manchado por providing MWCNTs

Efficient Capture and Isolation of Tumor-Related Circulating Cell-Free DNA from Cancer Patients Using Electroactive Conducting Polymer Nanowire Platforms.

Circulating cell-free DNA (cfDNA) is currently recognized as a key non-invasive biomarker for cancer diagnosis and progression and therapeutic efficacy monitoring. Because cfDNA has been detected in patients with diverse types of cancers, the use of efficient strategies to isolate cfDNA not only provides valuable insights into tumour biology, but also offers the potential for developing new cancer-specific targets. However, the challenges associated with conventional cfDNA extraction methods prevent their further clinical applications. Here, we developed a nanostructured conductive polymer platform for the efficient capture and release of circulating cfDNA and demonstrated its potential clinical utility using unprocessed plasma samples from patients with breast and lung cancers. Our results confirmed that the platform's enhanced efficiency allows tumor-specific circulating cfDNA to be recovered at high yield and purity.

ナノ構造化バイオセンサを用いた環境汚染物質の検出

We have discussed about a novel technique of developing a nanostructured polypyrrole biosensor for measurement of very low concentrations of hydrogen peroxide in liquid media. The proposed fabrication method is very effective in growing a nanostructured conductive polymer layer on a planar conductive substrate. In addition enzyme loading was done under a high electric field of 1 kV/m. The developed sensor provides a linear range of 0-200 µmol/l of hydrogen peroxide and a measurement sensitivity of 6.5 Acm-2 (mol/l)-1.

Visible-light active conducting polymer nanostructures with superior photocatalytic activity.

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.

Control of Conducting Polymer Nanostructures for Parahydrophobic Properties

Controlling the water adhesion is fundamental for various applications such as in water harvesting or liquid transportation. In nature, superhydrophobic properties (high apparent contact angles (Θ) and low water adhesion) as well as parahydrophobic properties (high Θ and high water adhesion) are present in flora and fauna. Here, in order to reproduce parahydrophobic properties, nanostructured conducting polymers are elaborated by electropolymerization of 3,4-propylenedioxythiophene (ProDOT) bearing phenyl groups. The use of phenyl groups allows to reduce the polymer surface energy in comparison to long fluorocarbon of hydrocarbon chains. We show that various fibrous morphologies as well as parahydrophobic properties can be controlled with the used electrolyte. This work is also important with the aim to replace long perfluorocarbon chains due to their bioaccumulative potential. This work also opens new doors to patent these kinds of materials and to envisage their commercialization. Keywords: Conducting polymers, electrochemistry, nanostructures, parahydrophobic, sticky, superhydrophobic, wettability.

ChemInform Abstract: Nanostructured Conductive Polymers for Advanced Energy Storage

AbstractReview: 54 refs.

Longitudinal and Lateral Integration of Conducting Polymer Nanowire Arrays via Block-Copolymer-Templated Electropolymerization

Pyrrole (Py) and thiophene derivatives were electropolymerized on a microphase-separated block copolymer [PEO-b-PMA(Az)] coated ITO electrode in order to form the corresponding conducting polymer nanostructures of perpendicularly oriented and hexagonally arranged cylinders as a template without the removal of one of the domains. Polypyrrole (PPy) nanowires grew through PEO cylindrical domains oriented perpendicular to the electrode to afford an array with an aspect ratio of up to 140 and a density of up to 4.4 × 1012 wires/in.2. Long, straight, π-stacked crystalline structures assigned to PPy main chains were observed in high-resolution TEM images of the individual wires. Additional elaborately crafted electropolymerization was demonstrated on a nanometer scale: (i) stepwise electropolymerization of Py and 3,4-ethylenedioxythiophene (EDOT) afforded segmented PPy–poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT–PPy wires with nanoheterojunctions and (ii) one-pot electropolymerization of a mixture of Py a...

Graphene oxide (GO)/reduced-GO and their composite with conducting polymer nanostructure thin films for non-volatile memory device

Graphene oxide (GO) was prepared by the conventional Hummer’s method and subsequently reduced (rGO) by the reduction process using hydrazine hydrate. Further, GO/rGO’s based composite with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) conducting polymer (CP) was prepared. The GO/rGO and CP-GO/rGO thin films were deposited on silicon substrate by drop-casting followed by air drying. Raman Spectroscopy, voltage–current (I–V) and polarization–electric field (P–E) measurements have been carried out to study the micro-structural, electrical and ferroelectric behaviors of GO/rGO and CP-GO/rGO thin films to understand the possibility of fabrication of non-volatile memory device. The linear voltage–current (I–V) relationship shows that the GO thin film behaves as semiconducting whereas rGO thin film behaves like conducting materials that are consistence with the results obtained from Raman spectroscopy measurement. The synthesized GO shows the symmetric log J–V curve with good hysteresis loop; whereas rGO shows similar symmetric curve with very small hysteresis loop. The CP-GO/rGO shows symmetric log J–V curve with very small hysteresis loop on the positive voltage side. The polarization–electric field (P–E) measurements shows that the polarization behavior of rGO is an ideal resistor response; whereas GO and CP-GO/rGO’s have lossy capacitor response (with the combined effects of capacitor and resistor) that are consistence with I–V measurements and could be used for non-volatile memory device.

Conducting polymer nanostructures for photocatalysis under visible light

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.

Polypyrrole-coated cotton fabrics for flexible supercapacitor electrodes prepared using CuO nanoparticles as template

Monodispersed inorganic oxide nanoparticles are one kind of the most commonly used templates for efficient and controllable preparation of conducting polymer nanostructures. In this article, we report the fabrication and characterization of PPy-coated cotton fabrics through in situ chemical polymerization by using CuO nanoparticles as template. The electrical conductivity of the coated samples increases dramatically to 10.0 S cm−1 with the introduction of CuO. The electrochemical properties of the obtained fabrics are examined by cyclic voltammetry and charge/discharge analysis. The increase of scan rate in the range of 5–50 mV s−1 has a small effect on the specific capacitance for the fabric electrode, pointing out the improved ion transportation in this electrode. The charge/discharge test further reveals that the fabric device shows high specific capacitance (225 F g−1 at a current density of 0.6 mA cm−2) and good cycling performance (about 92 % capacitance retention after 200 cycles) in aqueous electrolyte. These PPy-coated fabrics have potential to be used as electrode materials for wearable supercapacitors.

Controlling electrodeposited conducting polymer nanostructures with the number and the length of fluorinated chains for adjusting superhydrophobic properties and adhesion

Controlling the formation of surface nanostructures is highly important for various applications, and in particular for superhydrophobic properties.

Optical And Electrical Properties Of Conducting Polyaniline Nanofibers Synthesized By Interfacial And Rapid Mixing Polymerization

One dimensional conducting polymer nanostructures have been the focus of quite extensive studies worldwide due to their high aspect ratio, high porosity apart from high surface area to volume ratio. Conducting polyaniline nanofibers can be synthesized by various methods. In this paper, we report the preparation of polyaniline nanofibers with an average diameter of 40–70 nm by two different simple approach rapid mixing and interfacial polymerization. The key to producing polyaniline nanofibers is to suppress secondary growth. Based on this, interfacial polymerization and rapidly mixed reactions have been developed that can readily produce nanofibers by slightly modifying the conventional chemical synthesis of polyaniline without the need for any template or structural directing agent. Synthesized polyaniline (PANI) nanofibers were characterized by FTIR spectroscopy, Xray diffraction, transmission electron microscopy for their structural and UV-Vis absorption spectroscopy for optical properties. Direct and indirect transition energy gaps were determined from their Tauc plots. The absorption spectra show a linear fit for the transition. Electrical properties of the synthesized polyaniline nanofibers have been studied and the Arrhenius plots of electrical conductivity for the samples synthesized by rapid mixing and interfacial polymerization method show an approximate equal in their activation energy. The results obtained from optical and electrical properties are well compared, correlated and explained with respect to interfacial and rapid mixing polymerization techniques. Copyright © 2014 VBRI press.

Pulse electropolymerization synthesis of PPy(DBS) nanoparticle layers

A one-step process using a pulse electropolymerization technique is used to fabricate nanoparticles of polypyrrole (PPy) with dodecyl benzene sulfonate (DBS) anions from an aqueous solution without template and without using any chemical additives. The morphology of particles is controlled by changing the pulse duration (from 120 to 0.5 s), while keeping the relaxation time constant at 15 s. Short pulses resulted in the formation of PPy(DBS) nanoparticles with an average particle size of about 50 nm. The control of the size of the PPy(DBS) nanoparticles is ascribed to a pulse electropolymerization growth mechanism, whereby progressive nucleation associated with two-dimensional growth is initiated at each new pulse cycle from the equilibrium electrolyte solution. Short pulses are needed to avoid nonuniform growth of nanoparticles and control the particle size. Sufficiently long relaxation time is required to restore the equilibrium concentrations in the vicinity of the working electrode by suppressing the double layer. Combining short pulses with sufficiently long relaxation times enables the formation of PPy(DBS) nanoparticles. The proposed short-pulse technique is meant to be applied to the fabrication of a wide range of nanostructured conductive polymers.

Surface-dependent self-assembly of conducting polypyrrole nanotube arrays in template-free electrochemical polymerization.

One-dimensional conducting polymer nanostructure arrays could provide short ion transport paths, thus delivering superior chemical/physical performance and having large potential as intelligent switching materials. In this work, in situ electrochemical atomic force microscopy is employed to monitor the self-assembly of conducting polypyrrole nanotube arrays in template-free electrochemical polymerization. The specific spreading behavior of pyrrole micelles on the conductive substrate is important to large-area self-assembly of conducting polypyrrole nanotube arrays and the insight into self-assembly of conducting polypyrrole nanotube arrays is discussed. Moreover, compared with unoriented nanostructured polypyrrole, the conducting polypyrrole nanotube arrays possess enhanced electrical and electrochemical performances.

Synthesis And Characterization Of Nanofibers Of Conducting Polyaniline And Its Substitute Derivative

Intrinsically conducting polymers have been extensively studied due to their fascinating electronic properties and potential applications. One dimensional conducting polymer nanostructures have been the focus of quite extensive studies worldwide due to their high aspect ratio, high porosity apart from high surface area to volume ratio. In this paper, we report the synthesis of nanofibers of polyaniline and its substitute derivates and their comparative study in respect of electrical conductivity. Nanofibers of doped polyaniline (PANI), poly(o-methoxyaniline) (POMXA) and poly(o-methylaniline) (POMLA) were synthesized without need of any templates by interfacial polymerization. SEM, TEM, FTIR, UV-VIS and XRD were used to characterize the synthesized conducting polymeric materials. The average diameters of the synthesized nanofibers of conducting polymeric materials were in the range of 70-120 nm. The electrical conductivity was found to be in the range of 0.3 - 1.0 S/cm following the order as POMXA < POMLA < PANI which was found to be closely related to the size dependent electrical properties of the nanofibers. Optical band gap of these polymers was evaluated from UV–VIS absorption studies. Direct and indirect transition energy band gaps were determined from Tauc’s plots. Interfacial polymerization was shown to be readily scalable to produce bulk quantities of nanofibers of substitute derivative of polyaniline.

A facile method to synthesize polypyrrole nanoparticles in the presence of natural organic phosphate

The conductive polymers with unique nanostructures have attracted intense interest due to their potential application. Here the well-defined polypyrrole nanoparticles were facile fabricated via the facile chemical oxidative polymerization of pyrrole with high feeding ratio of phytic acid. Phytic acid is a renewable resource and a natural carbohydrate compound with a vast number of phosphate groups from plant which was used as the template and dopant for the nanostructured conductive polymer for the first time. The samples exhibit the well-defined nanoparticles observed by scanning electron microscope (SEM) and atomic force microscope (AFM). The PPy nanoparticles were achieved and outstanding electrical conductivity as high as 5263Sm−1 was obtained with the feeding mass ratio of phytic acid: pyrrole=3:7. Furthermore, the polypyrrole nanoparticles were characterized with Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and electrical conductivity techniques.

Confined Motion, Excitonic Migration, and Superradiance of Ordered Chlorophyll a Assembly Packed in Two Different Polypyrrole Nanostructures

The intermolecular excitonic migration in highly packed environment of light harvesting complex can be regulated by different peptide binding during photosynthesis. Porphyrin based conducting polymer nanostructures might be expected to exhibit similar behavior by introducing disorder through different interactions, thereby facilitating control over excitonic delocalization. Polypyrrole synthesized in the presence of two different chlorophyll a (CHL-a) species [spherical and cylindrical micelles] not only gives rise to two different nanostructures that are spherical and rod shaped (1D), evident from FESEM, but also differ in excitonic interactions, which is evident from fluorescence, UV–vis, and TCSPC experiments. The excitonic delocalization length and dipole–dipole coupling strength are higher in spherical species coupled with strong macrocyclic coordination resulting in enhanced superradiance. The ratio of radiative and nonradiative decay rate is higher in 1D nanostructure, implying that exciton decay r...

Fabrication of one-dimensional multifunctional poly-Schiff base bars by anodic aluminum oxide template

A simple strategy has been adopted for the fabrication of 1D nanobars PSB using anodic aluminum oxide template. Scanning electron microscope measurements provided direct evidence that the nanostructure showed a uniform width and depth in the appropriate time during the etch conditions. The electrochemical characteristics and the photovoltaic behaviors of PSB nanobar were characterized by cyclic voltammetry. The 1D conducting polymer nanostructures exhibited improved charge transport properties, and enhanced electrochemical properties, compared to their bulk polymer materials. And it also exhibited excellent electrochromic, acidochromic, and photoelectric characteristics.