PANI), Polypyrrole Research Articles

Heteroatom-Doped Carbon Nanostructures Derived from Conjugated Polymers for Energy Applications.

Heteroatom-doped carbon materials have been one of the most remarkable families of materials with promising applications in fuel cells, supercapacitors, and batteries. Among them, conjugated polymer (CP)-derived heteroatom-doped carbon materials exhibit remarkable electrochemical performances because the heteroatoms can be preserved at a relatively high content and keep stable under harsh working conditions. In this review, we summarized recent advances in the rational design and various applications of CP-derived heteroatom-doped carbon materials, including polyaniline (PANI), polypyrrole (PPy), and their ramification-derived carbons, as well as transition metal-carbon nanocomposites. The key point of considering CP-derived heteroatom-doped carbon materials as important candidates of electrode materials is that CPs contain only nonmetallic elements and some key heteroatoms in their backbones which provide great chances for the synthesis of metal-free heteroatom-doped carbon nanostructures. The presented examples in this review will provide new insights in designing and optimizing heteroatom-doped carbon materials for the development of anode and cathode materials for electrochemical device applications.

Nano-Mesh Structured Mn-Based Oxide/Conducting Polymer Composite Electrode for Supercapacitor

In this work, modified nano-mesh structured Mn-based oxide electrode material and the supercapacitors are researched. Three types of conducting polymers, i.e. polyaniline (PANI), polypyrrole (PPy) and polythiophene (PTs) are considered to modify Mn-based oxide electrodes. The results of field emission scanning electron microscope show that conducting polymer film can form porous structure on Mn-based oxide electrode, this special structure is beneficial to the improvement of specific surface area, so that the specific capacitance can be increased. The specific capacitance of the supercapacitors assembled by Mn-based oxide/conducting polymer composite electrodes are tested, resulting that the maximum initial specific capacitance is 843 F g-1, cycle life is 105 times. Compared to supercapacitors assembled by general Mn-based oxide electrodes, this Mn-based oxide/conducting polymer material electrode can improve the specific capacitance up to 1.4~1.9 times, and the conductivity and cycle stability can be increased at the same time.

Retrieval of Fluoride Using Polyaniline Polypyrrole Composite

This paper explains the possible use fo Polyaniline polypyrrole composite (PANi/PPy) as an adsorbent for the removal of the fluoride ions, from aqueous solution. The adsorption of the fluoride was appreciable around the natural pH of the aqueous solution of fluoride ions. This shows that adsorption of the fluoride ions could be carried out on the PANi/PPy composite without adjusting the pH of the medium. The experimental data yielded perfect fits with Freundlich isotherm equation. The values of the adsorption coefficients computed from the isotherms indicated the potential of the adsorbent for practical applications in defluoridation processes. Adsorption kinetics obeyed a first-order kinetic model. Diffusion of the fluoride ions into the micro pores and macro pores is the rate-determining step in the mechanism of the adsorption process. The adsorption of fluoride ions on the PANi/PPy composite was non-spontaneous and endothermic in nature with the defluoridation capacity increasing with increasing temperature due to increase in the rate of adsorption.The enthalpy change for the adsorption process was in the range of 25-67 kJ mol-1, which did not, indicates very strong chemical forces between the adsorbed fluoride ion and the PANi/PPy composite surface. This observation was well supported by the XRD pattern studies. Hence, physisorption seems to be the major mode of adsorption.

Flexible multiwalled carbon nanotubes/conductive polymer composite electrode for supercapacitor applications

The electrode performance of three types of selected electrically conductive polymers (ECPs), namely polyaniline, polypyrrole (PPy) and poly(3, 4-ethylenedioxythiophene) PEDOT (PSS:PEDOT) composite with multiwalled carbon nanotubes (MWCNTs) were investigated in this study. The capacitor electrode performance has been examined in both three electrodes half-cell and two electrodes device setups. The nano-composites were fabricated via polymerization of pseudocapacitive conductive monomer onto the MWCNT surface through the in situ chemical polymerization approach. Stainless steel thin foils were used as a current collector as well as a flexible backbone. Graphite conductive ink was used as the binder with the composite powder to form a conductive electrode layer. Half-cell electrochemical study was conducted to optimize the weight proportion between MWCNT and ECP in this parametric study. Two-electrode cell electrochemical study assessed the potential performance for the device. MWCNT was found to serve as the framework for polymerization of the ECP into a tubular structure. Among the three composites, it was discovered that the PPy/MWCNT composite has superior capacitor performance up to scan rate of 500 mV s−1.

Use of array of conducting polymers for differentiation of coconut oil products

An array of chemiresistors based on conducting polymers was assembled for the differentiation of coconut oil products. The chemiresistor sensors were fabricated through the potentiostatic electrodeposition of polyaniline (PANi), polypyrrole (PPy) and poly(3-methylthiophene) (P-3MTp) on the gap separating two planar gold electrodes set on a Teflon substrate. The change in electrical resistance of the sensors was measured and observed after exposing the array to the headspace of oil samples. The sensor response was found rapid, reversible and reproducible. Different signals were obtained for each coconut oil sample and pattern recognition techniques were employed for the analysis of the data. The developed system was able to distinguish virgin coconut oil (VCO) from refined, bleached & deodorised coconut oil (RBDCO), flavoured VCO, homemade VCO, and rancid VCO.

Polyaniline and polypyrrole/TiO2 nanocomposite coatings on Al1050: electrosynthesis, characterization and their corrosion protection ability in saltwater media

Polyaniline (PANI), polypyrrole (PPy) nanofilms, PANI/TiO2 and PPy/TiO2 nanocomposites were synthesized electrochemically on Al1050 electrode. The formation of PANI and PPy nanofilms and PANI/TiO2 and PPy/TiO2 nanocomposites was characterized by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), UV–visible absorption spectroscopy (UV–Vis), scanning electron microscopy (SEM), energy dispersion X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS). The comparative morphologic, spectroscopic and electrochemical properties of the prepared PANI and PPy nanofilms and nanocomposites were investigated in this study. The effectiveness of polymer and nanocomposite films in preventing the corrosion of Al1050 was tested in 3.5 % NaCl solution. For corrosion tests, anodic polarization curves and EIS were used to investigate their corrosion protection capability in saltwater solution. The highest, low frequency capacitance values were obtained as CLF = 60.76 and 12.8 mF cm−2 for PANI/TiO2 and PPy/TiO2 nanocomposites, respectively. The results of these studies revealed that the corrosion protection efficiency (PE) of the PANI/TiO2 (PE = 97.2 %), PPy/TiO2 (PE = 97.4 %) nanocomposites coated on Al1050 electrode was higher than that of PANI (PE = 96.4 %), PPy (PE = 94.9 %) and uncoated Al1050 electrodes. These nanocomposites can be used in airplanes, space technology, automobiles, electronics, and building sectors, as well.

Electroplating of nanostructured polyaniline–polypyrrole composite coating in a stainless-steel tube for on-line in-tube solid phase microextraction

In this work, a novel and efficient on-line in-tube solid phase microextraction method followed by high performance liquid chromatography was developed for preconcentration and determination of trace amounts of parabens. A nanostructured polyaniline–polypyrrole composite was electrochemically deposited on the inner surface of a stainless steel tube and used as the extraction phase. Several important factors that influence the extraction efficiency, including type of solid-phase coating, extraction and desorption times, flow rates of the sample solution and eluent, pH, and ionic strength of the sample solution were investigated and optimized. Under the optimal conditions, the limits of detection were in the range of 0.02–0.04μgL−1. This method showed good linearity for parabens in the range of 0.07–50μgL−1, with coefficients of determination better than 0.998. The intra- and inter-assay precisions (RSD%, n=3) were in the range of 5.9–7.0% and 4.4–5.7% at three concentration levels of 2, 10, and 20μgL−1, respectively. The extraction recovery values for the spiked samples were in the acceptable range of 80.3–90.2%. The validated method was successfully applied for analysis of methyl-, ethyl-, and propyl parabens in some water, milk, and juice samples.

Graphene oxide–polyaniline–polypyrrole nanocomposite for a supercapacitor electrode

Graphene oxide based nanocomposites were prepared through the in situ polymerization of aniline and pyrrole to study the interaction of graphene oxide with polyaniline (PANI) and polypyrrole (PPy).

Conducting polymers for corrosion protection: a review

Conducting polymers (CPs) such as polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) are used for the corrosion protection of metals and metal alloys. Several groups have reported diverse views about the corrosion protection by CPs and hence various mechanisms have been suggested to explain anticorrosion properties of CPs. These include anodic protection, controlled inhibitor release as well as barrier protection mechanisms. Different approaches have been developed for the use of CPs in protective coatings (dopants, composites, blends). A judicious choice of synthesis parameters leads to an improvement in the anticorrosion properties of the coatings prepared by CPs for metals and their alloys. This article is prepared as a review of the application of CPs for corrosion protection of metal alloys.

High-performance polymer/nanodiamond composites: synthesis and properties

Conjugated polymer/nanodiamond nanocomposites have been known as high-performance materials due to improved physical properties relative to conventional composites. In this attempt, novel conjugated polymer/nanodiamond nanocomposites were successfully prepared by in situ oxidative polymerization. Physical characteristics of the resultant nanocomposites were explored using Fourier transform infrared spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscope, differential scanning calorimeter, thermogravimetric analysis and X-ray diffraction spectroscopy. Structural analysis revealed the oxidative polymerization of various matrices [polyaniline (PANi), polypyrrole (PPy), polythiophene (PTh) and polyazopyridine (PAP)] over the surface of functionalized (F-NDs) and non-functionalized nanodiamonds (NF-NDs) thus ensuing NF-NDs/PAP/PANi/PPy, F-NDs/PAP/PANi/PPy, NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh nanocomposites. FESEM images depicted the fibrillar morphology of resulting nanocomposites with granular arrangement of nanofiller in matrix. Thermal analysis results showed that the functionalized F-NDs/PAP/PANi/PPy hybrid had higher value of 10 % weight loss around 489 °C relative to F-NDs/PANi/PPy/PTh with T10 at 471 °C. The glass transition temperature was found to be 99 and 105 °C for NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh, respectively. On the other hand, NF-NDS/PAP/PANi/PPy and F-NDs/PAP/PANi/PPy showed higher T g’s of 109 and 118 °C. The conductivity of NF-NDs/PAP/PANi/PPy was 3.8 Scm−1 and improved with the functionalized filler loading in F-NDs/PAP/PANi/PPy up to 5.4 Scm−1, while NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh had relatively lower values around 2.9 and 3.7 Scm−1, respectively. New conducting nanocomposites may act as useful contenders in significant industrial applications such as polymer Li-ion battery.

Facile Synthesis and Properties of Multilayered Polyaniline/Polypyrrole/Epoxy/Polystyrene/Functionalized Carbon Nanotube Composites

Single and multilayered nanocomposites of polyaniline (PANI), polypyrrole (PPy), Epoxy, polystyrene (PS) and functionalized carbon nanotubes (MWCNT) have been synthesized as PANI/MWCNTs, PPy/MWCNTs, Epoxy/MWCNTs, PS/MWCNTs, PANI/PPy/MWCNTs, PANI/PPy/Epoxy/MWCNTs and PANI/PPy/Epoxy/PS/MWCNTs. Layering of matrices on filler surface through layer-by-layer oxidative polymerization was confirmed by Fourier transform infrared spectroscopy. According to SEM, doubly layered PANI/PPy/MWCNTs revealed finely dispersed granular layer of polypyrrole over the surface of polyaniline. Thermogravimetric analysis of multilayered PANI/PPy/Epoxy/PS/MWCNTs showed degradation at enhanced temperature 400–750°C and char yield 45% at 900°C. Improvement in glass transition of layered material was observed from 275°C (PANI/PPyMWCNTs) −354°C (PANI/PPy/Epoxy/PS/MWCNTs).

Preparation and properties of multilayered polymer/nanodiamond composites via an in situ technique

Abstract Compared to conventional materials, nanocomposites of conjugated polymers are found to have excellent performance due to a larger exposed surface area. In this study, polyaniline (PANi), polypyrrole (PPy), polythiophene (PTh) and polyazopyridine (PAP)/nanodiamonds (NDs) composites were efficiently synthesized by in situ oxidative polymerization. Physical characteristics of fabricated nanocomposites were explored using Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FTIR indicated layer-by-layer oxidative polymerization of various matrices on functional ND (F-ND) surfaces. FESEM revealed the fibrillar (web-like) morphology of multilayered nanocomposites having a granular arrangement of NDs. TGA of multilayered F-NDs/PAP/PANi/PTh showed 10% degradation at an enhanced temperature of 482°C compared with F-NDs/PANi/PPy/PTh (471°C). Improvement in glass transition of layered material was observed from 99°C (NDs/PANi/PPy/PTh) to 121°C (NDs/PAP/PANi/PTh). Functional filler also contributed towards the enhancement in the conductivity of NDs/PAP/PANi/PTh (5.7 S cm-1) relative to NDs/PANi/PPy/PTh (3.7 S cm-1) systems. New conducting composites are potentially important in various applications, including polymer lithium-ion batteries.

Carbon-supported Fe/Co-N electrocatalysts synthesized through heat treatment of Fe/Co-doped polypyrrole-polyaniline composites for oxygen reduction reaction

In this paper, we synthesized cathode catalysts (PANI-PPYR, Fe/PANI-PPYR, Co/PANI-PPYR and Fe-Co/PANI-PPYR) with high performance oxygen reduction by using a simple heat treatment process. These catalysts were fabricated by directly calcining the Fe and/or Co doped polyaniline (PANI)-polypyrrole (PPYR) composites. Their electrocatalytic activity for ORR both in acidic and in alkaline media was investigated by voltammetric techniques. Among the prepared catalysts, Co/PANI-PPYR presents the most positive ORR onset potential of 0.62 V (vs. SCE) in 0.5 mol/L H2SO4 solution or −0.09 V (vs. SCE) in 1 mol/L NaOH solution. In addition, the Co/PANI-PPYR catalyst shows the largest limiting-diffusion current density for ORR, which is 4.3 mA/cm2@0.2 V (vs. SCE) in acidic and 2.3 mA/cm2@−0.3 V (vs. SCE) in alkaline media. In acidic media, a four-electron reaction of ORR on the Co/PANI-PPYR and Fe/PANI-PPYR catalysts is more dominant than a two-electron reaction. In alkaline media, however, a four-electron and a two-electron mechanisms are co-present for the ORR on all the prepared catalysts. Co/PANI-PPYR catalyst also presents good electrocatalytic activity stability for ORR both in acidic and in alkaline media.

Synthesis and Characterization of Polyaniline-Polypyrrole Composite

The current paper aims to study on synthesis of polyaniline (PANI)-polypyrrole (PPY) composite through simple interfacial polymerization method using chloroform as organic solvent, ammonium persulphate as an oxidant agent and sulphuric acid as a dopant. The composite was characterized by using Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and four pint probe methods. FESEM results showed the formation of fibrous PANI-PPY composite. FTIR and XRD results confirmed the successful formation of PANI-PPY composite. Four-point probe results showed the low electrical conductivity of the product. This study gives the better understanding on synthesis and characterization of the PANI-PPY through simple interfacial polymerization method.

Understanding the Role of Different Conductive Polymers in Improving the Nanostructured Sulfur Cathode Performance

Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies because of their high theoretical specific energy, but their wide-scale implementation has been impeded by a series of challenges, especially the dissolution of intermediate polysulfides species into the electrolyte. Conductive polymers in combination with nanostructured sulfur have attracted great interest as promising matrices for the confinement of lithium polysulfides. However, the roles of different conductive polymers on the electrochemical performances of sulfur electrode remain elusive and poorly understood due to the vastly different structural configurations of conductive polymer-sulfur composites employed in previous studies. In this work, we systematically investigate the influence of different conductive polymers on the sulfur cathode based on conductive polymer-coated hollow sulfur nanospheres with high uniformity. Three of the most well-known conductive polymers, polyaniline (PANI), polypyrrole (PPY), and poly(3,4-ethylenedioxythiophene) (PEDOT), were coated, respectively, onto monodisperse hollow sulfur nanopsheres through a facile, versatile, and scalable polymerization process. The sulfur cathodes made from these well-defined sulfur nanoparticles act as ideal platforms to study and compare how coating thickness, chemical bonding, and the conductivity of the polymers affected the sulfur cathode performances from both experimental observations and theoretical simulations. We found that the capability of these three polymers in improving long-term cycling stability and high-rate performance of the sulfur cathode decreased in the order of PEDOT > PPY > PANI. High specific capacities and excellent cycle life were demonstrated for sulfur cathodes made from these conductive polymer-coated hollow sulfur nanospheres.

Electrochemical preparation of polyaniline–polypyrrole solid-phase microextraction coating and its application in the GC determination of several esters

A novel polyaniline-polypyrrole (PANI-PPY) composite film coated stainless steel wire was prepared by cyclic voltammetry. Firstly, PANI was electrodeposited on a stainless steel wire from a solution containing 0.1 M aniline and 1M HNO3, after the PANI coating was dried in air PPY was electrodeposited on it from a solution containing 0.1 M pyrrole and 0.1 M p-methylbenzene sulfonic acid. The resulting PANI-PPY fiber showed reticulate structure and had large specific surface area. When it was used for the headspace solid-phase microextraction of several esters (i.e. methyl anthranilate, ethyl-o-aminobenzoate, dimethyl phthalate, methyl laurate, and diethyl phthalate), followed by gas chromatographic determination, it presented higher extraction capability in comparison with PPY and PANI coatings. Under the optimized conditions, the linear ranges were 0.07-300 μg L(-1) and the detection limits were 0.05-0.38 μg L(-1) for different esters. The PANI-PPY fiber also showed high durability, after being used for about 160 times its extraction capacity only changed a little. The proposed method was successfully applied to the determination of these esters in real samples and the recoveries were 90-102%.

Preparation of polyaniline–polypyrrole binary composite nanotube using halloysite as hard-template and its characterization

A facile approach toward self-assembly polyaniline–polypyrrole binary composite nanotubes (PAn–PPy-NTs) using halloysite as hard-template was adopted, and another innovation lied in the removal of halloysite as well as the secondary doping for the halloysite–polyaniline–polypyrrole composites (halloysite–PAn–PPy) in this study. The prepared composites were characterized with transmission electron microscope (TEM), FT-IR, X-ray diffraction (XRD), N2 adsorption–desorption isotherms and pore distribution (Brunauer–Emmett–Teller technique, BET), and thermogravimetric analysis (TGA) techniques. The eventual products had proved to be PAn–PPy-NTs after the template was removed from halloysite–PAn–PPy, and the formation process and growth mechanism of PAn–PPy-NTs were clarified and demonstrated, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS) were used for the comparision between halloysite–PAn–PPy and PAn–PPy-NTs. The results showed that the dual-doped PAn–PPy-NTs had better electrical property and were more promising for application in electrode materials, and the mechanism of secondary doping was also researched by X-ray photoelectron spectroscopy (XPS).

Polyaniline–Polypyrrole Composites with Enhanced Hydrogen Storage Capacities

A facile method for the synthesis of polyaniline-polypyrrole composite materials with network morphology is developed based on polyaniline nanofibers covered by a thin layer of polypyrrole via vapor phase polymerization. The hydrogen storage capacity of the composites is evaluated at room temperature exhibits a twofold increase in hydrogen storage capacity. The HCl-doped polyaniline nanofibers exhibit a storage capacity of 0.46 wt%, whereas the polyaniline-polypyrrole composites could store 0.91 wt% of hydrogen gas. In addition, the effect of the dopant type, counteranion size, and the doping with palladium nanoparticles on the storage properties are also investigated.

Hexavalent chromium removal mechanism using conducting polymers

We report detoxification of Cr(VI) into Cr(III) using electrochemically synthesized polyaniline (PANI), polypyrrole (PPY), PANI nanowires (PANI-NW) and palladium-decorated PANI (PANI-Pd) thin films. Percent Cr(VI) reduction was found to be decreased with an increase in pH from 1.8 to 6.8 and with initial Cr(VI) concentration ranging from 2.5 to 10mg/L. Efficacy of PANI increased at higher temp of 37°C as compared to 30°C. PANI-Pd was found to be most effective for all three initial Cr(VI) concentrations at pH 1.8. However, efficacy of PANI-Pd was significantly reduced at higher pHs of 5 and 6.8. Efficacy of PANI and PANI-NW was found to nearly the same. However, there was a significant reduction in effectiveness of PANI-NW at 10mg/L of Cr(VI) at all the three pHs studied, which could be attributed to degradation of PANI-NW by higher initial Cr(VI) concentration. PPY and PANI-NW were found to be highly sensitive with respect to pH and Cr(VI) initial concentration. Chromium speciation on PANI film was carried out by total chromium analysis and XPS, which revealed Cr(III) formation and its subsequent adsorption on the polymer. PANI-Pd and PANI are recommended for future sensor applications for chromium detection at low pH.

Removal of toxic nitrate ions from drinking water using conducting polymer/MWCNTs nanocomposites

New application of conducting polymers as stable nanocomposites for nitrate ion exchange materials in water and wastewater treatment and for environmental protection is introduced in this work. The nanocomposites of multi-walled carbon nanotubes (MWCNTs) with different polymers such as: polyaniline (PANI), polypyrrole (PPY), poly(1,8-diaminonaphthalene) [P(1,8-DAN)] and poly(2-vinylpyridine) (P2VP) were synthesized with different dopants as effective and reusable nanocomposites for nitrate removal from drinking water. Nitrate anions at toxic concentrations were removed from water using ion exchange mechanism without any toxic byproducts. The obtained results demonstrate that effective ion exchange occurs between NO3 − and Cl−. There are some protonated heteroatoms in polymer chains that are bonded with anions of dopants and their counter ions in nanocomposites. These dopant anions on the =NH+– groups of polymers can be exchanged with NO3 − in water. Adsorption of NO3 − on polymer/MWCNTs nanocomposites showed dependency to some parameters. Different experimental parameters such as pH and temperature of the sample, polymers dopant, and the ratio of polymer to MWCNTs in nanocomposites affect the amount of nitrate removal. The highest removal efficiency was achieved at 1.20 g L−1 of PANI/MWCNTs (3:1) nanocomposite, pH = 6.5 and ambient temperature. After five successive cycles of nitrate removal, this parameter was still up to 70 % compared to the first run (up to 80 %).