Electrochemical capacitor composed of doped polyaniline and polymer electrolyte membrane

We prepared polyaniline doped with LiPF₆ and HCl, respectively, using chemical methods. The electrode composite was attached to both sides of Al mesh, while the polymer electrolyte mixture was spread on a glass plate. Then, the polyaniline‐based redox supercapacitor was fabricated using two electrodes and a polymer electrolyte membrane. The electrochemical performance of the redox supercapacitor was investigated by using the charge/discharge method, cyclic voltometry, and impedance spectroscopy. The initial specific capacitance was ≈115 F/g and it retained ≈90 F/g even after 5000 cycles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1300–1304, 2003     

Role of a chelating agent in the formation of polyaniline films on aluminum

A chelating agent, alizarin, was used to pretreat an aluminum surface before the electrochemical synthesis of polyaniline. Alizarin had two main effects on the process: (1) it suppressed the hydrogen evolution reaction and increased the current efficiency and (2) it stabilized the open‐circuit potential in a corroding environment, such as in 0.1M NaCl. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 819–823, 2003     

Dielectric properties of thin films of Babassu‐based polymer and polyaniline blends

In the present work, we describe the preparation and subsequent characterization of polymeric blends consisting of a monoglyceride (MG) synthesized from the Babassu's oil and the already commonly employed polyaniline (PAni). By following changes in the complex impedance of capacitor‐like devices we observe that the presence of MG in the PAni/MG blends decreases electrical conductivity and that this decrease is a function of the content of MG in the blend, i.e., the blend with 30% of MG shows Z′ about seven times greater than the one with 10% of MG. Fourier transform infrared measurements prove the formation of MG and the presence of secondary amine groups (N? H bonds) in the blends, which allow for the chemical doping of PAni by protonation, further studies are necessary to access the viability of employing this new material as active layer in electronic organic devices. Atomic force microscopy images show the formation of agglomerates due to the presence of MG. In addition, the polymeric mixture acts only as a blend, providing a physical interaction between different components. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46198.     

Electropolymerization of aniline in phosphonium‐based ionic liquids and their application as protective films against corrosion

Conductive polyaniline (PANI) films were deposited on mild steel by an electropolymerization technique in the presence of different types of phosphonium‐based ionic liquids, including tetrabutylphosphonium bromide, tetraoctylphosphonium bromide, and ethyltributylphosphonium diethylphosphate. The formation of the PANI films was followed by repetitive cyclic voltammetry scans and was confirmed with diffuse reflectance infrared Fourier transform spectroscopy. The morphology, surface roughness parameters, and grain sizes of these coatings were evaluated by atomic force microscopy. The corrosion behavior of the bare and PANI‐coated electrodes was investigated by potentiodynamic polarization, open‐circuit potential, and electrochemical impedance spectroscopy techniques in a simulated marine environment in 3.5 wt % aqueous NaCl solutions. The quantum chemical parameters of the PANI composite films were also calculated with parametric method 3, a semi‐empirical quantum mechanical method. The theoretical conclusions were found to be consistent with the reported experimental data. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43923.     

In situ thermal polymerization of an ionic liquid monomer for quasi‐solid‐state dye‐sensitized solar cells

In situ thermal polymerization of a model ionic liquid monomer and ionic liquids mixture to form gel electrolytes is developed for quasi‐solid‐state dye‐sensitized solar cells (Q‐DSSCs). The chemical structures and thermal property of the monomers and polymer are investigated in detail. The effect of iodine concentration on the conductivity and triiodide diffusion of the gel electrolytes is also investigated in detail. The conductivity and triiodide diffusion of the gel electrolytes increase with the increasing I₂ concentration, while excessive I₂ contents will decrease the electrical performances. Based on the in situ thermal polymeric gel electrolytes for Q‐DSSCs, highest power conversion efficiency of 5.01% has been obtained. The superior long‐term stability of fabricated DSSCs indicates that the cells based on in situ thermal polymeric gel electrolytes can overcome the drawbacks of the volatile liquid electrolyte. These results offer us a feasible method to explore new gel electrolytes for high‐performance Q‐DSSCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42802.     

Synthesis and electrochemical properties of hollow polyaniline microspheres by a sulfonated polystyrene template

Hollow polyaniline microspheres (HMsPANI) for supercapacitors were prepared successfully with sulfonated polystyrene microspheres as the template. The prepared electrode materials of HMsPANI consisted of nanoparticles and, thus, had a hierarchical structure. The electrochemical behaviors of the materials were investigated with cyclic voltammetry and galvanostatic charge–discharge tests. A maximum specific capacitance of 421 F/g was achieved in a 1M H₂SO₄ solution, with the potential ranging from ?0.2 to 0.8 V (vs a saturated calomel electrode), in a three‐electrode glass cell at room temperature for the HMsPANI electrode. This suggested its potential application in electrochemical capacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Electrochemical and optical properties of dicyclohexylmethyl substituted poly(3,4‐propylenedioxythiophene) analogue

An analogue of disubstituted 3,4‐propylenedioxythiophenes, namely 3,3‐bis(cyclohexylmethyl)‐3,4‐dihydro‐2H‐thieno[3,4‐b][1,4]dioxepin (ProDOT‐CycHex₂), was synthesized and its electrochemical polymerization was carried out successfully in an electrolyte solution of 0.1 M tetrabutylammonium hexafluorophosphate dissolved in a mixture of acetonitrile and dichloromethane (3/1: v/v). The corresponding polymer called PProDOT‐CycHex₂ has a reduced band gap of 1.85 eV and an electrochromic property: blue/violet when neutralized and highly transparent when oxidized. Also, PProDOT‐CycHex₂ film exhibited faster response time (0.7 s) and higher coloration efficiency (769 cm²/C) during oxidation when compared to its benzyl substituted analogue. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46214.     

Variable‐emittance infrared electrochromic skins combining unique conducting polymers,ionic liquid electrolytes,microporous polymer membranes,and semiconductor/polymer coatings,for spacecraft thermal control

Variable emittance (ε) is a property vital for the increasing needs in thermal control of future microspacecraft. This article describes fabrication, function, and performance of thin‐film, flexible, variable‐emittance (V‐E) electrochromic skins that use a conducting polymer/‐Au/‐microporous membrane (CP/Au/µP) base, and a new, unique ionic liquid electrolyte (IonEl). Poly(aniline‐co‐diphenyl amine) with a long‐chain polymeric dopant is used as the CP. A unique, patented device design yields no barrier between the active, electrochromic CP surface and the external environment, except for a thin, infrared‐transparent semiconductor/polymer film that lowers solar absorptance [α(s)] and protects from atomic‐O/far‐UV. Use of the IonEl requires special activation methods. Data presented show tailorable ε variations from 0.19 to 0.90, Δε values of >0.50 (which is the highest reported thus far for any functional V‐E material, to our knowledge), α(s) < 0.35, and nearly indefinite cyclability. Extended space durability testing, including calorimetric thermal vacuum and continuous light/dark cycling over >7 months under space conditions (<10^?5 Pa vacuum, far‐UV), show excellent durability. Other data show resistance to solar wind, atomic‐O, electrostatic discharge, and micrometeoroids. These lightweight, inexpensive, advanced polymeric materials represent the only technology that can work with micro‐ (<20 kg) and nano‐ (<2 kg) spacecraft, thus eventually allowing for much greater flexibility in their design and potentially “democratizing” the entire space industry, for example, allowing small firms to launch their own, dedicated satellites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40850.     

Fabrication and characterization of hybrid films based on polyaniline and graphitic carbon nitride nanosheet

Hybrid films of polyaniline/graphitic carbon nitride (PANI/g‐C₃N₄) deposited on titanium was fabricated. First, g‐C₃N₄ as a two‐dimensional graphite‐like structure was synthesized by the stepwise condensation reaction of melamine and cyanuric chloride in the presence of N,N‐dimethylmethanamide as a high boiling point nonnucleophilic base. Then composite films of PANI/g‐C₃N₄ were prepared by in situ electrochemical polymerization of an aniline solution containing g‐C₃N₄. Different concentrations of g‐C₃N₄ were utilized to improve the electrochemical performances of the hybrids. The resulting PANI/g‐C₃N₄ composite films were characterized by X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible diffuse reflection spectroscopy techniques. The electrochemical performance of the composites was evaluated by cyclic voltammetry (CV). Application of the prepared samples has been evaluated as supercapacitor material in 0.5 M H₂SO₄ solution using CV technique. The specific capacitances of PANI/g‐C₃N₄ composite films were higher than obtained for pure PANI films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44059.     

Synthesis and characterization of conducting homopolymers and copolymers of o‐anisidine and o‐toluidine in inorganic and organic supporting electrolytes

The influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o‐anisidine), poly(o‐toluidine), and poly(o‐anisidine‐co‐o‐toluidine) thin films was investigated. Homopolymer and copolymer thin films were synthesized electrochemically, under cyclic voltammetry conditions, in aqueous solutions of inorganic acids (H₂SO₄, HCl, HNO₃, H₃PO₄, and HClO₄) and organic acids (benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid) at room temperature. The films were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and conductivity measurements with a four‐probe technique. The ultraviolet–visible spectra were obtained ex situ in dimethyl sulfoxide. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic electrolytes used, whereas in organic acid supporting electrolytes, ES formed only with oxalic acid. Moreover, the current density and conductivity of the thin films was greatly affected by the nature and size of the anion present in the electrolyte. For the copolymer, the conductivity lay between the conductivity of the homopolymers, regardless of the supporting electrolyte used. The formation of the copolymer was also confirmed with differential scanning colorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2634–2642, 2003     

The performance of epoxy coatings containing polyaniline (PANI) nanowires in neutral salt,alkaline, and acidic aqueous media

PANI/epoxy coatings have great promise applications in the industry as the metal corrosion protection coating, and their performance directly determines the life span of the coating and equipment durability. In this study, the performance of epoxy coatings with and without PANI nanowires immersed in 12 wt% NaCl, 5 wt% HCl, and 5 wt% NaOH solutions at different temperature were investigated for the first time. The performance and the degradation reactions of the coating cooperated with PANI nanowires were characterized by the variety of techniques and methods, including ultraviolet–visible spectrophotometry (UV–vis), field emission scanning electron microscopy (SEM), Attenuated Total Reflectance-Fourier transform Infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA). The experiment results indicated that the failure mechanism of the different coatings varied with the different temperatures and solutions. Electrochemical impedance spectra (EIS) results showed that an appropriate content of PANI nanowires improve the protection performance of epoxy coatings in 12 wt% NaCl, 5 wt% HCl, and 5 wt% NaOH solutions, which is attributed to the passivation ability and shielding effect of PANI nanowires.     

Ionic liquid gated poly(triaryl amine) thin film field effect transistor

A poly(triaryl amine) thin film field effect transistor was investigated in air with ionic liquid (IL) gating for the first time. The transistor retained a high-on/off ratio of ~700 and mobility of ~10⁻² cm²/V-s. When compared to a transistor based on the conducting polymer polyaniline under similar operating conditions, it was found to exhibit superior performance. Significantly low-operating voltages (±1 V) enhances the possibility of its use in organic electronics. The device was successfully tested for binary operation, and we demonstrate its suitability for use in low-power consumption electronic circuits.     

XPS study of aged polyaniline films

In this article, a study of the aging of conducting Polyaniline–Polystyrene blends using X‐ray photoelectron spectroscopy (XPS) and UV‐visible‐near IR analysis is presented. The physicochemical results are compared to those obtained by electrical measurements. XPS results confirm the existence of an oxidation process also deduced by the electrical conductivity studies. The N1s and S2p core level spectra decomposition allows to show that a deprotonation process and cyclization of tertiary amine occur during aging. The absorption spectrum shows a decrease of delocalized charges and the apparition of localized polarons after a long aging time. All these mechanisms are responsible of the electrical conductivity decrease observed during aging at elevated temperature. The results are presented for films of PANI–CSA–PSt blends, but the conclusions can be extended to pure conducting PANI–CSA films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3730–3736, 2003     

Preparation and electrochemical properties of polyaniline/reduced graphene oxide composites

Polyaniline (PANI)/reduced graphene oxide (rGO) composites were synthesized by in situ oxidative polymerization of aniline on reduced graphene sheets. Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy were used to characterize the composites. The results indicated PANI/rGO composites were produced and contained covalent bonds between the functional groups of PANI and rGO. A uniform coating of PANI on the rGO sheets had a synergistic effect on the properties of the composites. The electrochemical properties of the PANI/rGO composites produced using different feed ratios of aniline to rGO were studied. The results showed that the composites exhibited a maximum specific capacitance of 797.5 F/g at 0.5 A/g and minimum charge transfer resistance of 0.98 Ω when the feed ratio of aniline to rGO was 2:1. These values were superior to those of pure PANI and rGO. The composites also displayed excellent cycling stability, with specific capacitance retention of 92.43% after 1000 cycles. These stable structural composites show promise for the development of new supercapacitor applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46103.     

Preparation and characterization of composites of polyaniline nanorods and multiwalled carbon nanotubes coated with polyaniline

Composites of polyaniline (PANI) nanorods and multiwalled carbon nanotubes (MWNTs) coated with PANI were prepared by in situ polymerization with perchloric acid as a dopant. Transmission electron microscopy images showed that the coexisting composites of PANI nanorods and MWNTs coated with PANI were formed at low MWNT contents. The interaction between MWNTs and PANI was proved by Fourier transform infrared and ultraviolet–visible spectra. The electrical conductivity of a dedoped PANI/MWNT composite with a 16.3 wt % concentration of MWNTs reached 3.0 × 10^?3 S/cm, which was 6 orders of magnitude higher than that of dedoped PANInanorods. The results also showed that coexisting composites of PANI nanorods and MWNTs coated with PANI had high electrochemical activity and good cyclic stability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Pulsed‐plasma‐polymerized aniline thin films

An inductively coupled pulsed‐plasma reactor was used to synthesize polyaniline thin films on several substrates positioned at various distances from the center of the radio frequency (RF) coil. The samples were characterized with Fourier transform infrared (FTIR), cyclic voltammetry, and microscopic techniques. Impedance spectroscopy was used to determine the electrical characteristics of three‐layer structures with polyaniline as the middle layer between top and bottom metal electrodes. FTIR results indicated that the chemical composition and structure of the films were very dependent on the substrate's position with respect to the RF coil, there being considerably less aromatic character closer to the coil. The electrochemical behavior of the films in acidic electrolytes was similar to that of small‐molecule aniline oxidation products; the number of peaks in the cyclic voltammograms varied with the substrate. Scanning electron microscopy indicated that as the films became thicker, they developed nodules atop a somewhat smoother underlayer. Results from transmission electron microscopy and optical birefringence suggested that the films were not completely homogeneous. The impedance measurements were consistent with relatively rough films possibly containing pinholes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93:1317–1325, 2004     

Facile fabrication of superhydrophobic polyaniline structures and their anticorrosive properties

We report a simple approach for the preparation of superhydrophobic polyaniline (PANI) and its application for the corrosion protection coatings. First, PANI was synthesized conventionally by oxidative polymerization with APS. Subsequently, PANI with different wettability was obtained by modification with different surfactants. The surface modification of PANI with three different surfactants (sodium dodecylbenzenesulfonate, polyethylene glycol, and cetyltrimethylammonium bromide) provided excellent surface superhydrophobicity (water contact angle >150°). The structure and morphology of as‐prepared PANI were characterized with Fourier transform infrared, Energy dispersive X‐ray spectroscopy, and Scanning electron microscopy. Corrosion protection performance of PANI with different wettability was evaluated in 3.5% NaCl electrolyte using Tafel polarization curves and electrochemical impedance spectroscopy. The results indicated that various superhydrophobic PANI coatings have better anticorrosion performance as compared to the hydrophilic PANI. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44248.     

Role of dual dopants in highly ordered crystalline polyaniline nanospheres: Electrode materials in supercapacitors

Aniline is oxidized by ammonium persulfate oxidant with a weak organic acid, 1,3‐(6,7)‐napthalene trisulfonic acid (NTSA), via an aqueous polymerization pathway to polyaniline (PANI) salt. The effects of the sodium lauryl sulfate surfactant, mineral acid [sulfuric acid (H₂SO₄)], and a combination of surfactant with mineral acid in the aniline polymerization reaction are also carried. These salts were designated as PANI–NTSA–dodecyl hydrogen sulfate (DHS), PANI–NTSA–H₂SO₄, and PANI–NTSA–DHS–H₂SO₄, respectively. Interestingly, PANI–NTSA–DHS showed a highly ordered crystalline sample with a nanosphere morphology. These PANIs were used as electrode materials in supercapacitor applications. Among the four salts, the PANI–NTSA–DHS–H₂SO₄ material showed higher values of specific capacitance (520 F/g), energy (26 W h/kg), and power densities (200 W/kg) at 0.3 A/g. Moreover, 77% of the original capacitance was retained after 2000 galvanostatic charge–discharge cycles with a Coulombic efficiency of 98–100%. PANI–NTSA–DHS–H₂SO₄ was obtained in excellent yield with an excellent conductivity (6.8 S/cm) and a thermal stability up to 235°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42510.     

Electrochemical behavior of a Nafion‐membrane‐based solid‐state supercapacitor with a graphene oxide—multiwalled carbon nanotube—polypyrrole nanocomposite

In this study, we sprayed a graphene oxide–multiwalled carbon nanotube (GM) suspension in isopropyl alcohol–water onto a Nafion membrane. The electrodeposition of polypyrrole (PPy) was carried out on Nafion to complete the fabrication of a solid‐state symmetric supercapacitor. Nafion 117 membranes are used as electrolyte separators in the preparation of supercapacitors. The characterization of the symmetric supercapacitor was done by X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the symmetric solid‐state supercapacitor were investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques in 1M lithium chloride. A specific capacitance of 90.4 mF/cm² (258.3 F/g¹) was obtained for the supercapacitor at a scan rate of 10 mV s^?1. Maximum energy and power densities of 10 W h/kg and 6031 W/kg were obtained for the fabricated supercapacitor. In such a symmetric configuration, the highly interconnection networks of GM–PPy provided good structure for the supercapacitor electrode, and the good interaction between PPy and GM provided fast electron‐ and charge‐transportation paths so that a high capacitance was achieved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44926.     

Polyaniline salt containing dual dopants,pyrelenediimide tetracarboxylic acid,and sulfuric acid: Fluorescence and supercapacitor

Storage of energy is considered as the most germane technologies to address the future sustainability. In this study, aniline was chemically oxidized with a controlled concentration of pyrelenediimide tetracarboxylic acid (PDITCA) by ammonium persulfate to polyaniline salt (PANI‐H₂SO₄‐PDITCA), with nanorods morphologies, having a sensibly decent conductivity of 0.8 S cm^?1, wherein H₂SO₄ was generated from ammonium persulfate during polymerization. PANI‐H₂SO₄‐PDITCA salt showed bathochromic fluorescence shift (595 nm) compared to PDITCA (546 nm). The Brunauer–Emmett–Teller surface area of the PANI‐H₂SO₄‐PDITCA‐25 and PANI‐H₂SO₄‐PDITCA‐50 were 18.3 and 21.4 m² g^?1, respectively. Furthermore, its energy storage efficiency was evaluated by supercapacitor cell configuration. The composite PANI‐H₂SO₄‐PDITCA‐50 showed capacitance 460 F g^?1 at 0.3 A g^?1 and large cycle life 85,000 cycles with less retention of 77% to its original capacitance (200 F g^?1) even at a better discharge rate of 3.3 A g^?1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45456.