Electrochemical Polymerization Method Research Articles

In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells.

This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30 nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3−/I− redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs.

Preparation of sulfonated graphene/polypyrrole solid-phase microextraction coating by in situ electrochemical polymerization for analysis of trace terpenes

In this study, a novel sulfonated graphene/polypyrrole (SG/PPy) solid-phase microextraction (SPME) coating was prepared and fabricated on a stainless-steel wire by a one-step in situ electrochemical polymerization method. Crucial preparation conditions were optimized as polymerization time of 15min and SG doping amount of 1.5mg/mL. SG/PPy coating showed excellent thermal stability and mechanical durability with a long lifespan of more than 200 stable replicate extractions. SG/PPy coating demonstrated higher extraction selectivity and capacity to volatile terpenes than commonly-used commercial coatings. Finally, SG/PPy coating was practically applied for the analysis of volatile components from star anise and fennel samples. The majority of volatile components identified were terpenes, which suggested the ultra-high extraction selectivity of SG/PPy coating to terpenes during real analytical projects. Four typical volatile terpenes were further quantified to be 0.2–27.4μg/g from star anise samples with good recoveries of 76.4–97.8% and 0.1–1.6μg/g from fennel samples with good recoveries of 80.0–93.1%, respectively.

Electrosynthesis of Polythiophene Nanowires and Their Application for Sensing of Chlorpromazine

Highly ordered polythiophene nanowires have been synthesized by using anodic aluminum oxide (AAO) template through electrochemical polymerization method. The resultant fiber-like polymer structures were identified by the field-emission scanning electron microscopy with diameter of the order of ca 100 nm and a length of up to several micrometers. Different characterizations including SEM, TEM and EDS were employed to prove that conducting polythiophene nanowires were synthesized successfully by this facile method. The synthesized polythiophene nanowires were used for modification of glassy carbon electrode (GCE) for electrochemical sensing of chlorpromazine hydrochloride (CPZ). Under optimal conditions, the proposed sensor could be used for determination of CPZ ranging from 0.1 to130.0 μM with a low detection limit of 0.03 μM (S/N = 3). The prepared sensor possessed accurate and rapid response to CPZ and good stability, sensitivity, repeatability, and no interference by a number of potentially interfering substances. Furthermore it showed an average recovery of 97.9% in human plasma.

Preparation and electrochemical catalytic application of nanocrystalline cellulose doped poly(3,4-ethylenedioxythiophene) conducting polymer nanocomposites

Nanocrystalline cellulose doped conducting polymer PEDOT nanocomposites can be prepared through both chemical (right) and electrochemical (left) polymerization methods.

Controllable synthesis of vertically aligned polypyrrole nanowires as advanced electrode support for fuel cells

Here, we develop a facile electrochemical polymerization method for the synthesis of polypyrrole (PPy) nanowires on Pd modified Nafion® membranes. Interestingly, with altering the deposition potential and temperature, we can easily tune the PPy nanowires from disordered nanostructures to well ordered vertically aligned nanowires. The various PPy nanowires show similar electronic conductivity but diverse hydrophobicity/hydrophilicity. The ordered PPy nanowires can significantly facilitate the mass transport and enhance the catalyst utilization. These two factors together make an obvious performance improvement of fuel cells.

The influence of monomer concentration on the optical properties of electrochemically synthesized polypyrrole thin films

Polypyrrole (PPy) thin films were deposited on stainless steel and ITO coated glass substrate at a constant deposition potential of 0.8 V versus saturated calomel electrode (SCE) by using the electrochemical polymerization method. The PPy thin films were deposited at room temperature at various monomer concentrations ranging from 0.1 M to 0.3 M pyrrole. The structural and optical properties of the polypyrrole thin films were investigated using an X-ray diffractometer (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), and ultraviolet—visible (UV—vis) spectroscopy. The XRD results show that polypyrrole thin films have a semi crystalline structure. Higher monomer concentration results in a slight increase of crystallinity. The polypyrrole thin films deposited at higher monomer concentration exhibit high visible absorbance. The refractive indexes of the polypyrrole thin films are found to be in the range of 1 to 1.3 and vary with monomer concentration as well as wavelength. The extinction coefficient decreases slightly with monomer concentration. The electrochemically synthesized polypyrrole thin film shows optical band gap energy of 2.14 eV.

One-step electrosynthesis of multi-walled carbon nanotube/poly-ortho-aminophenol composite film and investigation of its electrocatalytic properties

In this study, one-step electrochemical polymerization method was developed for the fabrication of multi-walled carbon nanotubes/poly-ortho-aminophenol (MWCNTs/PoAP) composite film to detect oxytetracycline. The fabricated nanocomposite shows good stability and enhanced electrocatalytic ability for the detection of oxytetracycline. The resulting composite can be used as electrode material in an electrochemical capacitor. Scanning electron microscopy and electrochemical methods have been used to characterize the MWCNTs/PoAP nanocomposite film.

Functionalized graphene/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate as counter electrode catalyst for dye-sensitized solar cells

A (grapheme/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate) graphene/PEDOT:PSS composite film was electrodeposited on fluorine-doped tin oxide conductive substrate by one-step electrochemical polymerization method. The low-cost and platinum-free film was used as counter electrode in (dye-sensitized solar cell) DSSC. The cyclic voltammetry, electrochemical impedance spectroscopy and Tafel measurements indicate that the graphene/PEDOT:PSS composite film has low charge-transfer resistance on the electrolyte/electrode interface and high catalytic activity for the reduction of triiodide to iodide and. As a result, the DSSC based on the graphene/PEDOT:PSS counter electrode showed high power conversion efficiency of 7.86% under a simulated sunlight illumination of 100 mW cm−2 (AM 1.5), which is comparable with the performance of the DSSC based on Pt counter electrode (7.31%).

Fast switching and high contrast electrochromic device based on PEDOT nanotube grown on ZnO nanowires

The present work reports preparation of an electrochromic device based on poly(3,4-ethylenedioxythiophene) (PEDOT) modified ZnO nanowires. The vertically aligned ZnO nanowires, being 70nm in diameter, were prepared as a template by hydrothermal process on 65nm ZnO seed layer sputtered on transparent conductive fluorine doped tine oxide substrate. PEDOT was synthesized by electropolymerization using two approaches. The first was prepared at 1.6V constant potential (CP) and the second by 0–2V cyclic voltammetry (CV). The PEDOT nanotubes were successfully grown on ZnO nanowires array by CV electrochemical polymerization but CP method led to formation of PEDOT thin film. The average wall thickness of nanotubes was 20nm. The CV and CP electrodes and devices were characterized by scanning electron microscope, cyclic voltammetry analysis and UV–visible spectrophotometery to study the effect of preparation method on electrode morphology and device stability, response time (tR) and contrast. The CV approach gave rise to tR and contrast of 66ms and 46.1%, respectively; CP method resulted in tR and contrast of 300ms and 37.84%, respectively. While the conventional thin films had response time in order of second.

Poly(3-alkyltellurophene)s Are Solution-Processable Polyheterocycles

The synthesis and characterization of a series of poly(3-alkyltellurophene)s are described. Polymers are prepared by both electrochemical and Kumada catalyst transfer polymerization methods. These polymers have reasonably high molecular weights (M(n) = 5.4-11.3 kDa) and can be processed in a manner analogous to that of their lighter atom analogues. All examples exhibit red-shifted optical absorption, as well as solid-state organization, as evidenced by absorption spectroscopy and atomic force microscopy. Overall, the synthesis and characterization of these materials open up a wide range of future studies involving tellurium-based polyheterocycles.

Both p and n-Dopable, Multichromic, Napthalineimide Clicked Poly(2,5-dithienylpyrrole) Derivatives

Herein we disclose construction and characterization of both p- and n-dopable, multichromic 2,5-dithienylpyrrole (SNS) based electrochromic films and demonstrate usefulness of click chemistry on functionalization of SNS derivatives to enhance optoelectronic properties of the resultant polymer. For this purpose, 1,8-naphthalimide containing monomer (SNS-Napth) was synthesized through click chemistry for the first time. SNS-Napth was subjected to electrochemical polymerization and electrochromic properties of the resultant polymer was investigated in detail. Additionally, 16 different copolymers were synthesized by controlling electrochemical copolymerization conditions such as feed ratio, electrochemical polymerization method and potential. All the polymers revealed ambipolar redox behavior where reversible n- and p-type doping was achieved in cathodic and anodic regime, respectively. The homopolymer had a bandgap of 3.15 eV and displayed yellow-blue color variation upon doping. Copolymers, on the other hand, displayed multichromic behavior where a direct correlation between polymerization conditions (feed ratio, polymerization potential) and spectral behavior, color was determined. Among all copolymers, the ones which were synthesized in excess EDOT medium displayed higher reversibility and shorter switching times whereas amplification of polymerization potential seems to be ineffective in terms of switching times.

A novel conical structure of polyaniline nanotubes synthesized on ITO-PET conducting substrate by electrochemical method

The conical nanotube structure of polyaniline (PANI) was facilely synthesized on indium tin oxide (ITO) conducting polyethylene terephthalate (PET) substrates via electrochemical polymerization method. The tubular morphology of PANI was confirmed by SEM and TEM images. It was observed that one side of PANI conical nanotube was a sharp closed tip, and the other was a circular open tube. In addition, the nanosheets, nanofibers and nanorods of PANI were observed by SEM with polymerization potentials varying from 2.0V to 2.6V. The resulting materials were also characterized by four-probe instrument, FTIR, cyclic voltammetry, and photoelectric measurement. Then the results showed that the optimal efficiency of dye sensitized solar cell (DSSC) with flexible PANI/ITO-PET counter electrode at 2.4V reached to 0.86%, owing to the unique conical nanotube structure, excellent photoelectric property and high electrochemical activity of this PANI electrode. Therefore, the PANI/ITO-PET electrode can be applied as promising flexible electrode materials for DSSCs.

A novel electrochromic and broad infrared emissivity modulation film based on the copolymer of aniline and o-anisidine

A novel electrochromic film based on the copolymer of aniline and o-anisidine was obtained by electrochemical polymerization method. The electrochromic properties of the novel film were investigated by cyclic voltammetry and amperometric i–t curve. The optical properties of the film were investigated by UV–vis spectrophotometer and FT-IR spectroscopy. The results show that different colors of the electrochromic film could be achieved, which exhibits as light grass green, emerald green and blue-violet. The maximum difference of the UV–vis absorption of the film is about 60% between −0.6V and 1.0V, respectively. The biggest different average emissivity dynamic of the film is 0.408 in the wavelength of 8–14μm region.

Template-free electrochemical synthesis and electrochemical supercapacitors application of polyaniline nanobuds

One-step and template-free synthesis of polyaniline nanobuds (PANI NBs), synthesized using anodic electrochemical polymerization method, is reported at room temperature onto a conducting indium-tin-oxide glass substrate. The PANI NBs are characterized for their structural, morphological, and electrochromic properties. Scanning electron microscopy image reveals NBs type architecture, perpendicular to the substrate surface. These NBs are broader at their bottoms and narrower at the tops. Individual NB has confirmed 30 nm top diameter and 100–200 nm length. Electrochemical supercapacitive behavior of the PANI NBs electrode is investigated by measuring cyclic voltammetry curves. Moderate specific capacitance of 128 F/g is achieved in the potential range of −0.2 to 1.0 V at 10 mV/s sweep rate in 0.5 M H2SO4 electrolyte. Influence of inner and outer charges on a resultant specific capacitance is also investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Thermal Degradation Behavior of Polythiophene-modified Montmorillonite Nanocomposite

Polythiophene (PTh) nanoparticles was synthesized by cationic surfactant assisted dilute polymerization method using FeCl3 as oxidant. The physical characterizations of the synthesized PTh nanoparticles were studied by FT-IR and XRD, DSC, SEM. Polythiophene (PTh)/clay nanocomposites were successfully synthesized with montmorillonite modified with Cetyl-Trimethyle - Ammonium Bromide (CTAB) and Didocyl Dimet hyl-Ammonium Bromide (DDAB), 1bromohexadecane (MSAB). The thermal degradation behavior of polythiophene (PTh) in PTH/Na+-montmorillonite (Na+-MMT) nanocomposites prepared by in-situ intercalative polymerization of thiophene into Na+-MMT has been investigated by thermogravimetric analysis (TGA) and X-ray diffraction (XRD), SEM. It was found that the PTh obtained by cationic surfactant assisted dilute polymerization method had better capacitor performances than the same obtained by the conventional chemical and electrochemical polymerization methods. The nanocomposites suggest that the PTh chains for PTh/Na+-MMT nanocomposites are more thermally stable than those for a pure PTh. This improvement in the thermal stability for the nanocomposites is attributed to the presence of Na+-MMT nanolayers with a high aspect ratio acting as barriers, thus shielding the degradation of PTh in the nanogalleries and also hindering the diffusion of degraded PTh from the nanocomposites. The shielding effect of the nanolayers is found to be significant as the Na+-MMT content in the PTh/Na+-MMT nanocomposites is increased. The XRD patterns of the nanocomposites after TGA measurements indicate that the basal spacing (d001) of the PTh/Na+-MMT nanocomposites is almost intact, implying that the thermal decomposition of the PTh chains is believed to occur mainly outside the silicate layers.

Conductance and series resistance measurements of polyaniline/p-Si and polypyrrole/InP junction devices

Polyaniline/p-Si/Al and polypyrrole/p-InP rectifying devices were fabricated. Electrochemical polymerization method has been used for obtaining the polymer films. Some electrical characteristics, such as current–voltage and conductance–voltage/frequency measurements were analyzed. From the I–V characteristics of the devices ideality factor and barrier height values were found as n=2.12, Φ=0.79eV and n=1.68, Φ=0.59eV for polyaniline/p-Si/Al and polypyrrole/p-InP devices respectively. Series resistance Rs calculations were performed as a function of temperature for polyaniline/p-Si/Al device. The values of Rs decreased with temperature for this device. The voltage and temperature dependence of Rs were attributed to the particular distribution density of interface states and interfacial insulator or polymer layer. The conductance–voltage and conductance–frequency characteristics of polypyrrole/p-InP device were investigated at room temperature. It has been seen that the effect of the series resistance is negligible for polypyrrole/p-InP device.

Application of Poly(3,4-ethylenedioxythiophene):Polystyrenesulfonate/Polypyrrole Counter Electrode for Dye-Sensitized Solar Cells

A low-cost poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and polypyrrole (PPy) composite film was fabricated on a rigid fluorine-doped tin oxide (FTO) substrate used as the counter electrode in a dye-sensitized solar cell (DSSC) by a facile electrochemical polymerization method. The cyclic voltammetry and electrochemical impedance spectroscopy measurements show that the PEDOT:PSS/PPy film has a low surface resistance, high conductivity, and good catalytic performance for the I–/I3– electrolyte. The power conversion efficiency of the DSSC based on the PEDOT:PSS/PPy counter electrode reaches 7.60% under a simulated solar light illumination of 100 mW·cm–2; the efficiency is comparable to that of the DSSCs based on a sputtered Pt electrode.

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in one-tenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators.

Battery Characteristics of Nanocrystalline V2O5 and Conductive Polymer Composite Film Cathodes

Composite films of nanocrystalline V2O5 embedded in a conducting polymer, poly-3,4-ethylenedioxythiophene (PEDOT), were grown using an electrochemical polymerization method. The nanobeam-shaped V2O5 and PEDOT composite film cathodes have high capacities, excellent rate capabilities and cycling stabilities: the specific capacity was 269 mAhg-1 and the degradation rate was only 8% after 100 consecutive cycles at 1 C rate. The charge transfer resistances (Rct) for the nanobeam-V2O5/PEDOT composite film cathodes were smaller than that for the nanobeam-V2O5 powder cathode, in the electrochemical impedance measurements. The diffusion coefficient (DLi+) in the nanobeam-V2O5 crystallines was calculated to be approximately 4.6 x 10-8, and the values of DLi+ for each of α-, ε-, and δ-LixV2O5 crystalline phases, reversibly formed in the composite films during the discharging and charging processes, were able to be estimated in the range of (2.1~9.8) x 10-10.

Effect of temperature on the capacitance–frequency and conductance–voltage characteristics of polyaniline/p-Si/Al MIS device at high frequencies

A polyaniline/p-Si/Al MIS device has been fabricated by forming a polyaniline layer on Si by using the electrochemical polymerization method. The conductance–voltage and capacitance–frequency measurements have been performed as a function of temperature. The capacitance of the device decreased with increasing frequency. The increase in capacitance results from the presence of interface states. The peaks have been observed in the conductance curves of the device and attributed to the presence of an interfacial layer between polyaniline and p-Si. For each temperature, the plot of series resistance/voltage gave a peak. The voltage and temperature dependence of series resistance has been attributed to the particular distribution density of interface states and the interfacial insulator layer.