Starch-assisted synthesis of polypyrrole nanowires by a simple electrochemical approach

Starch, one of the most commonly used polysaccharides, has been adopted for the first time as morphology-directing agent to the electrochemical synthesis of polypyrrole (PPy) nanowires on various electrodes.     

Characteristics of polypyrrole (PPy) nano-tubules made by templated ac electropolymerization

Electrochemical alternating current (ac) method designed for the synthesis of polypyrrole (PPy) nano-tubule arrays is the topic of this paper. Two-step anodic aluminum oxide (AAO) membrane is used as a template. The morphology of PPy nano-tubules is observed by SEM and discussed. FTIR spectra exhibit that the peaks of PPy nano-tubules shift compared to conventional PPy film.     

Towards precise synthesis of functional polymers by iterative electropolymerization

正The controllable synthesis of polymers and macromolecules with precise structures is one of the biggest challenges in polymer chemistry [1]. Although polymers with welldefined architectures and compositions could now be prepared by various living polymerization techniques [1], it remains elusive to produce macromolecular materials with precise controls of monomer sequences and easy purification procedures.     

Facile synthesis of polypyrrole coated copper nanowires: a new concept to engineered core-shell structures

Polypyrrole coated copper nanowires were synthesized in a one-pot manner in the presence of cupric precursor and pyrrole. They displayed ultra-high sensitivity as a potentiometric sensor with considerable environmental stability comparable to noble metals.     

Carbazole derivative synthesis and their electropolymerization

This review article investigates the hot topics by presenting the latest advances in carbazole and its derivative synthesis and their electropolymerization processes. The carbazole-based compounds are particularly attractive due to their important photochemical and thermal stability and good hole-transport ability. Conjugated monomers of carbazole derivatives and their polymers attract interest due to their suitability in a broad range of applications, such as biosensors, corrosion inhibition, photovoltaics, electroluminescent devices, field-effect transistors and supercapacitors, etc. This review article divides two main parts. One of them includes effects of electropolymerization parameters of carbazole and chemical polymerization of carbazole derivatives. In addition, copolymers and composites of carbazole derivatives were presented in the first part. In the second part, the application of polycarbazole and its derivatives was examined as biosensors, corrosion inhibition, supercapacitor, battery, fuel cell, solar cell, electropolymerization, light emitting diodes, and OLEDs.     

Templateless assembly of molecularly aligned conductive polymer nanowires: a new approach for oriented nanostructures

Although oriented carbon nanotubes, oriented nanowires of metals, semiconductors and oxides have attracted wide attention, there have been few reports on oriented polymer nanostructures such as nanowires. In this paper we report the assembly of large arrays of oriented nanowires containing molecularly aligned conducting polymers (polyaniline) without using a porous membrane template to support the polymer. The uniform oriented nanowires were prepared through controlled nucleation and growth during a stepwise electrochemical deposition process in which a large number of nuclei were first deposited on the substrate using a large current density. After the initial nucleation, the current density was reduced stepwise in order to grow the oriented nanowires from the nucleation sites created in the first step. The usefulness of these new polymer structures is demonstrated with a chemical sensor device for H(2)O(2), the detection of which is widely investigated for biosensors. Finally, we demonstrated that controlled nucleation and growth is a general approach and has potential for growing oriented nanostructures of other materials.     

Electrochemical supercapacitive properties of polypyrrole thin films: influence of the electropolymerization methods

A detailed study of the effects of different electropolymerization methods on the supercapacitive properties of polypyrrole (PPy) thin films deposited on carbon cloth is reported. Deposition mechanisms of PPy thin films through cyclic voltammetry (CV), potentiostatic (PS), and galvanostatic (GS) modes have been analyzed. The resulting PPy thin films have been characterized by X-ray photoelectron spectroscopy (XPS), SEM, and TEM. The electrochemical properties of PPy thin films were investigated by cyclic voltammetry and galvanostatic charge/discharge. The results showed that the different electrodeposition modes of synthesis significantly affect the supercapacitive properties of PPy thin films. Among different modes of electrodeposition, PPy synthesized by a potentiostatic mode exhibits maximum specific capacitance of 166 F/g with specific energy of 13 Wh/kg; this is attributed to equivalent proportions of the oxidized and neutral states of PPy. Thus, these results provide a useful orientation for the use of optimized electrodeposition modes for the growth of PPy thin films to be applied as electrode material in supercapacitors.     

Naphthobipyrrole: versatile synthesis and electropolymerization

A facile synthetic route to a new polycyclic pyrrole derivative, 3,8-diethyl-1,10-dihydro-benzo[e]pyrrolo[3,2-g]indole (1), is reported. This annulated bipyrrole acts as a monomer for electropolymerization and forms an electrochromic conducting polymer (poly1) when electrooxidized at low potentials (0.4 V vs Ag/Ag(+)) in acetonitrile. The presence of alkyl substituents at the 3 and 8 carbons (β-pyrrolic positions) induces regioselective 2,5'-coupling of the pyrrole repeat units and gives rise to the more uniform polymeric product, poly1. Poly1 exhibits globular morphology, as judged from SEM pictures. Its spectroelectrochemical features can be attributed to the formation of four possible states: neutral, polaron, bipolaron, and transverse bipolaron. The relatively low switching potentials (-0.6 to +0.9 V vs Ag/Ag(+) in MeCN) displayed by poly1 leads us to suggest that 1 has a role to play as a polymerizable moiety for the development of multicolor electrochromic materials.     

导电聚吡咯纳米线的电化学无模板法可控合成与表征

以β-萘磺酸(NSA)为掺杂剂,采用电化学无模板法制备了聚吡咯(PPy)纳米线.研究了NSA浓度、吡咯(Py)单体浓度及反应温度对PPy纳米线形貌的影响.分别采用场发射扫描电子显微镜(FE-SEM)和拉曼光谱对PPy纳米线的结构形貌和化学结构进行了表征.结果表明,利用电化学无模板法可得到中空的PPy纳米线;NSA浓度会影响PPy纳米线的取向性;增大Py单体浓度,可制得圆锥状PPy纳米线;低温有利于合成形状细长、紧密堆积的PPy纳米线.PPy纳米线形貌受游离Py浓度及Py-NSA胶束数量影响,通过调节NSA浓度、Py浓度及反应温度改变游离Py浓度及Py-NSA胶束数量,可制得不同形貌的PPy纳米线.     

Coordinated organogel templated fabrication of silver/polypyrrole composite nanowires

A new method to fabricate metal/conducting polymer composite nanowires is presented by taking silver/polypyrrole composite nanowires as an example.A silver(Ⅰ)-coordinated organogel as template was prepared firstly,and redox-polymerization of pyrrole took place on the gel fiber,giving product of silver/polypyrrole nanowires.The silver/polypyrrole nanowires were characterized by multiple techniques.This strategy could be carried out in one-step procedure at room temperature,and it proves the utility of coordinated organogels in template synthesis of polymer nanostructures.     

Bulk synthesis of polypyrrole nanofibers by a seeding approach

The morphology of doped polypyrrole.Cl powder changes dramatically from granular to nanofibrillar when a very small amount (1-4 mg) of V2O5 nanofibers are added to a chemical oxidative polymerization of pyrrole in aq 1.0 M HCl using (NH4)2S2O8 as the oxidant. Unlike the polyaniline system, a key synthetic requirement in the polypyrrole system is for the seed template to be "active", i.e., to be capable of independently oxidizing the pyrrole monomer. Thin, strongly adherent films can be obtained on inert surfaces such as glass, plastics, etc., directly from the polymerization mixture without any bulk product isolation steps, significantly simplifying the processing of these nanofibers.     

Application of polypyrrole nanowires for the development of a tyrosinase biosensor

Polypyrrole nanowires (PPyNWs) were fabricated and examined as a structural component of amperometric biosensor matrix. An enzyme, tyrosinase (TYR), was immobilized onto PPyNWs using glutaraldehyde (GA). Matrix composite morphology was investigated using scanning electron microscopy. Electrochemical behavior of the prepared PPyNWs/GA/TYR biosensor towards catechol was studied and the assessment of its analytical characteristics was carried out taking into account linear range, sensitivity, repeatability, reproducibility and operational stability.     

Controllable synthesis of conducting polypyrrole nanostructures

Wire-, ribbon-, and sphere-like nanostructures of polypyrrole have been synthesized by solution chemistry methods in the presence of various surfactants (anionic, cationic, or nonionic surfactant) with various oxidizing agents [ammonium persulfate (APS) or ferric chloride (FeCl3), respectively]. The surfactants and oxidizing agents used in this study have played a key role in tailoring the nanostructures of polypyrrole during the polymerization. It is inferred that the lamellar structures of a mesophase are formed by self-assembly between the cations of a long chain cationic surfactant [cetyltrimethylammonium bromide (CTAB) or dodeyltrimethylammonium bromide (DTAB)] and anions of oxidizing agent APS. These layered mesostructures are presumed to act as templates for the formation of wire- and ribbon-like polypyrrole nanostructures. In contrast, if a short chain cationic surfactant octyltrimethylammonium bromide (OTAB) or nonionic surfactant poly(ethylene glycol) mono-p-nonylphenyl ether (Opi-10) is used, sphere-like polypyrrole nanostructures are obtained, whichever of the oxidizing agents mentioned above is used. In this case, micelles resulting from self-assembly among surfactant molecules are envisaged to serve as the templates while the polymerization happens. It is also noted that, if anionic surfactant sodium dodeyl surfate (SDS) is used, no characteristic nanostructures of polypyrrole were observed. This may be attributed to the doping effect of anionic surfactants into the resulting polypyrrole chains, and as a result, micelles self-assembled among surfactant molecules are broken down during the polymerization. The effects of monomer concentration, surfactant concentration, and surfactant chain length on the morphologies of the resulting polypyrrole have been investigated in detail. The molecular structures, composition, and electrical properties of the nanostructured polypyrrole have also been investigated in this study.     

Electrochemical synthesis of novel polypyrrole microstructures

Polypyrrole microstructures with unusual morphologies have been synthesized by direct electrochemical oxidation of pyrrole in beta-naphthalenesulfonic acid aqueous solution.     

Electrochemical synthesis of polypyrrole in powder form

Journal of Solid State Electrochemistry - Novel approach to synthesis of conjugated oligomers/polymers is proposed. This approach combines all advantages of electrochemical methods: variation of...     

Preparation of polypyrrole/multi-walled carbon nanotube hybrids by electropolymerization combined with a coating method for counter electrodes in dye-sensitized solar cells

In this work, multi-wall carbon nanotubes coated with polypyrrole (PPy/MWCNT) have been used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). PPy was deposited onto fluorine-doped tin-oxide-coated glass by electrochemical polymerization of pyrrole. Three surfactants were used in the preparation of the hybrids: cationic cetyltrimethylammonium bromide, anionic sodium dodecylbenzenesulfonate (DBSNa), and non-ionic polyoxyethylene sorbitan monolaurate (Tween20). The morphologies of the PPy and PPy/MWCNT hybrids were investigated using scanning electron spectroscopy. Chemical composition of the prepared CEs was determined by X-ray photoelectron spectroscopy and Fourier-transformed infrared spectroscopy. The catalytic activity of the PPy and PPy/MWCNT layers was evaluated using cyclic voltammetry, and the photovoltaic properties of DSSCs with PPy and PPy/MWCNT CEs were characterized using I–V measurements. PPy/MWCNT samples that were prepared by electrochemical polymerization showed the best results when the anionic surfactant DBSNa was used during polymerization. The photoelectric conversion efficiency of PPy/MWCNT prepared by electrochemical polymerization was 2.9%, which was 59% of that of Pt CE (4.9%).