Dulse‐derived porous carbon–polyaniline nanocomposite electrode for high‐performance supercapacitors

Dulse‐derived porous carbon (DDPC)–polyaniline (PANI) nanocomposites were fabricated by a method based on the in situ chemical oxidation polymerization of aniline on DDPC. The characterization of the material showed that the nano‐PANI was grown on the surface of DDPC in the form of nanosticks or nanoparticles. The DDPC–PANI nanocomposites were further used as electrode materials for energy‐storage applications. Meanwhile, the effect of the amount of aniline on the electrochemical performance of DDPC–PANI was also investigated. The results show that a maximum specific capacitance of 458 F/g was achieved for the DDPC–PANI nanocomposites; this was higher than that of the DDPC electrode (218 F/g), and the PANI electrode (318 F/g). The specific capacitance of DDPC–PANI remained 66.0% of the initial value after 5000 cycles; this was higher than that of PANI (50.5%). Finally, a device of DDPC–PANI–activated carbon (AC) was assembled with DDPC–PANI as a positive electrode, which exhibited a high energy density of 9.02 W h/kg, which was higher than that of PANI–AC device. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45776.     

Interfacial polymerization of poly(2,5‐dimethoxyaniline) and its enhanced capacitive performances

The poly(2,5‐dimethoxyaniline) (PDMA) were synthesized through interfacial polymerization method using three various organic solvent/water reaction systems. As comparison with conventional chemical polymerized PDMA, the interfacial polymerization can produce uniform nanoparticular PDMA, especially for using high density (higher than water) solvent as organic phase. The capacitive performances of interfacial polymerized PDMA can be benefited from its uniform morphologies and loose packing structure. The specific capacitance of interfacial polymerized PDMA using carbon tetrachloride is 194 Fg^?1 at current density of 50 mA cm^?2, which has 59% enhancement over 122 Fg^?1 of conventional PDMA at the same current density. The energy density of interfacial polymerized PDMA is 39 Wh kg^?1 at current density of 5 mA cm^?2 and the power density is 28,421 W kg^?1 at current density of 50 mA cm^?2. The energy density has improvement in different extent as comparison with that of conventional PDMA. The enhanced capacitive performances can be attributed to the increased ionic conductivity induced by the loose molecular packing structure and uniform morphology produced by the interfacial polymerization process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40666.     

Surface‐tethered conjugated polymers created via the grafting‐from approach

Polyacrylate brushes with pendent terthiophenes [poly(terthiophene methyl methacrylate) (PTTMM)] were successfully grown from indium tin oxide and gold with surface‐initiated atom transfer radical polymerization. The films formed on both substrates were characterized by ellipsometry and Fourier transform infrared spectroscopy. Using cyclic voltammetry, we electrochemically crosslinked the PTTMM brush to form a conjugated polymer network. The conjugation lengths in the film were increased as evidenced by ultraviolet–visible spectroscopy. Additionally, an atomic force microscopy study on the surface‐modified solid substrate revealed the formation of a smooth and uniform polymer brush with a low surface roughness, even after electrochemical crosslinking. These uniformly grafted conducting polymer brushes may find use in photovoltaic devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41363.     

Electrical properties of nitric acid and DMSO treated PEDOT:PSS/n-Si hybrid heterostructures for optoelectronic applications

Organic/inorganic heterostructures are an emerging and interesting field of research for optoelectronics. In this work, an efficient organic/inorganic hybrid heterojunction between PEDOT:PSS and n-type Silicon has been fabricated for optoelectronic applications. Samples with varying thickness of PEDOT:PSS were prepared by spin coating technique and the electrical conductivity of organic layers was modified using DMSO as additive. Post fabrication, the hybrid heterostructures were treated with HNO₃ vapor so as to enhance the conductivity of the organic layer. Surface treatment with HNO₃ was found to lower the roughness of the organic layer and enhance the transparency of the layer. I–V characteristics reveal optimized behavior of HNO₃ treated PEDOT:PSS layer with a low Ideality factor (n~3.2) and a barrier height (Φ_B) of 0.8 eV. The findings of the study provide a promising efficient method to enhance the electrical and device properties of PEDOT:PSS/n-Si heterostructures for optoelectronic applications. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48952.     

Aqueous in-situ electrosynthesis and electrochromic performance of PEDOT:PSS/Reline film

Poly(3,4-ethylene dioxythiophene) (PEDOT) is a promising electrochromic material in many practical application, such as smart windows and displays. However, there are still difficulties in currently realizing green manufacturing, high coloration efficiency, and rapid response. Herein, in-situ electrochemical polymerization of PEDOT:PSS/Reline films was suggested in aqueous solution. Deep eutectic solvents (DES) composed of choline chloride and urea (Reline) were employed as green solvents in reaction system and used as dopants for the PEDOT:PSS. The as-prepared PEDOT:PSS/Reline films exhibited remarkable electrochromic properties, including great ion diffusion coefficient, fast reaction time (coloration response time was 1.4 s), prominent transmittance modulation (38%), high coloration efficiency (223 cm²/C) and excellent cyclic stability. Impressively, doping of Reline cannot only provide a green polymerization environment, but also significantly boost the electrochromic properties.     

Fabrication of flexible transparent electrodes using PEDOT:PSS and application to resistive touch screen panels

The flexible transparent electrodes were fabricated by line patterning of conductive inks consisting of poly(3,4‐ethylenedioxythiophene) doped with poly(4‐styrenesulfonic acid) (PEDOT:PSS) water dispersion, ethylene glycol, isopropyl alcohol, and tetraethoxysilane (TEOS) on polyethylene terephthalate (PET) films. The values of sheet resistance (R_s), total light transmittance, haze, figure‐of‐merit, and pencil hardness of the PEDOT:PSS‐TEOS/PET film were found to be 301 Ω/sq., 85.0%, 2.4%, 41, and 2H, respectively. Furthermore, a resistive touch screen panel was fabricated using the PEDOT:PSS‐TEOS/PET film as the top electrode. It was found that the drawing on the resistive touch screen panel was successfully displayed on the PC screen with good in‐plane uniformity and maximum linearity of 0.8%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45972.     

Multifunctional polyaniline–tin oxide (PANI–SnO2) nanocomposite: Synthesis,electrochemical, and field emission investigations

Synthesis of PANI–SnO₂ nanocomposite has been performed using a simple two step chemical oxidative polymerization route. The structural, morphological and chemical properties of the as‐synthesized PANI–SnO₂ nanocomposite have been revealed by various characterization techniques such as SEM, TEM, XRD, FTIR, and XPS. Interestingly the as‐synthesized PANI–SnO₂ nanocomposite exhibits supercapacitance value of 721 F g^?1 with energy density 64 Wh kg^?1, which is noticed to be higher than that of pristine SnO₂ and PANI nanostructures. Furthermore, the galvanostatic charge–discharge characteristics revealed pseudocapacitive nature of the PANI–SnO₂ nanocomposite. The estimated values of charge transfer resistance and series resistance estimated from the Nyquist plot are found to be lower. Along with the supercapacitive nature, PANI–SnO₂ nanocomposite showed promising field emission behavior. The threshold field, required to draw emission current density of 1 μA/cm², is observed to be 0.90 V/μm and emission current density of 1.2 mA/cm² has been drawn at applied field of ～2.6 V/μm. The emission current stability investigated at preset values of 0.02 and 0.1 mA/cm² is observed to be fairly stable over duration of more than 3 h. The enhanced supercapacitance values, as well as, the promising field emission characteristics are attributed to the synergic effect of SnO₂ nanoparticles and PANI nanotubes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41401.     

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.     

Novel chemically synthesized polyaniline electrodes containing a fluoroboric acid dopant for supercapacitors

The performance of chemically synthesized dual‐acid‐doped polyaniline (PANI) electrode material was investigated for supercapacitors for the first time. Three different grades of PANI‐containing fluoroboric acid (HBF₄) as one of the dopants were prepared by a chemical polymerization method. PANI–dodecylhydrogen sulfate–HBF₄ salt was synthesized by an emulsion polymerization pathway. A PANI–HBF₄–sodium tetrafluoroborate composite and PANI–HBF₄ salt were prepared from different modifications of dopants by a dedoping–redoping process. Capacitative behaviors of the three grades of PANI electrode materials were investigated. Among the three different grades of PANI, PANI–HBF₄ electrode showed the best performance in terms of conductivity (2.3 × 10^?1 S/cm), specific capacitance of the supercapacitor (140 F/g), specific energy (9.6 W h/kg), and specific power (58.8 W/kg). An increase in the capacitance of PANI–HBF₄ was achieved, which identified the significant contribution of the dedoping–redoping processes in the PANI system for supercapacitors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fabrication of Tiron‐doped polypyrrole/MWCNT composite electrodes with high mass loading and enhanced performance for supercapacitors

In this study, the aromatic sulfonate compound Tiron with high charge to mass ratio is used as an anionic dopant for synthesis of polypyrrole (PPy). The fabricated PPy is investigated for electrochemical supercapacitor (ES) application. Testing results show that Tiron allows reduced PPy agglomeration, smaller particle size and improved charge storage properties of PPy. High capacitance and improved capacitive retention at high scan rates are achieved by the fabrication of PPy/multiwalled carbon nanotube (MWCNT) composite electrode using safranin (SAF) as a co‐dispersant. The Tiron‐doped PPy electrode shows the highest capacitance of 7.8 F cm^?2 with a mass of 27 mg cm^?2. The Tiron‐doped PPy/MWCNT composite electrode shows good capacitance retention with a capacitance of 1.0 F cm^?2 at the scan rate of 100 mV s^?1. Symmetric supercapacitor cells are fabricated using PPy based active materials. An energy density of 0.36 mWh cm^?2 is achieved. The energy/power density and capacitance retention of the Tiron‐doped PPy/MWCNT ES is significantly improved in comparison with PPy‐based ES, prepared without Tiron or MWCNT. The Tiron‐doped PPy/MWCNT symmetric supercapacitor presents good cycling performance with 91.4% capacitance retention after 1000 charge–discharge cycles. The PPy/MWCNT composites, prepared using Tiron and SAF co‐dispersant, are promising electrodes for ES. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42376.     

Low‐potential electrochemical polymerization of 6‐nitroindole and characterization of its polymers

Conducting polymers bearing nitro substituents are very important from both academic and industrial viewpoints. However, it is very difficult to electrosynthesize such conducting polymers because of the strong electron‐withdrawing effect of nitro groups. In this article, we describe the electrochemical synthesis of films of a new conducting polymer, high‐quality poly(6‐nitroindole) (P6NI), by direct anodic oxidation of 6‐nitroindole in boron trifluoride diethyl etherate containing 10% (v/v) diethyl ether. The oxidation potential onset of 6‐nitroindole in this medium has been measured to be just 0.98 V versus a saturated calomel electrode (SCE), which is much lower than that determined in acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (1.6 V vs SCE). Thermal studies have revealed that P6NI displays good thermal stability. The electrical conductivity of the P6NI films has been measured to be 0.08 S/cm. Structural studies have shown that the polymerization of the 6‐nitroindole ring occurs mainly at the 2,3‐positions. Fluorescence spectral studies have shown that the principal excitation and emission peaks of P6NI are at 416 and 535 nm, respectively, with a fluorescence quantum yield of 0.05. All these properties of P6NI films may facilitate their potential applications in various fields, such as electrochemical sensors and green‐light‐emitting materials. To the best of our knowledge, this is the first report on the electrosynthesis and characterization of 6‐nitro‐substituted polyindole films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Li‐ion conductivity in PEO‐graphene oxide nanocomposite polymer electrolytes: A study on effect of the counter anion

Graphene oxide (GO) has been prepared by modified Hummer's method for their incorporation as nanofiller in designing nanocomposite polymer electrolytes (NCPEs). Prior to use the GO nanofillers has been characterized by TEM, FTIR, and Raman studies to elucidate their nanostructure, functionality, and purity. The various poly(ethylene oxide) (PEO)‐based NCPEs has been prepared by incorporating GO nanofillers in presence of three different lithium salts, viz., CF₃SO₃Li, LiTFSI, and LiNO₃ as the source of Li‐ions and then casted into free standing polymeric films. The change in PEO crystallinity has been studied considering their full width half maximum values of respective diffraction peaks in the XRD spectra. The Li‐ion conductivity of various NCPEs has been studied from impedance spectroscopy. All the NCPE films show optimum value of Li‐ion conductivity with 0.3% GO nanofiller content irrespective of the source of Li‐ions used. But, variation of the Li‐ion conductivity values is occurred for all the three studied lithium salts. Both LiTFSI and LiNO₃ salts display Li‐ion conductivity in the order of 10^?4 S cm^?1 whereas CF₃SO₃Li in the order of 10^?6 S cm^?1, all in presence of 0.3% GO nanofillers. The change in conductivity values of the NCPEs has been explained by correlating with Argand plots and also with change in PEO crystallinity, which occurs due to various relaxation processes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46336.     

Specroelectrochemical,switching kinetics,and chronoamperometric studies of dibenzyl derivative of poly(3,4‐propylenedioxythiophene) thin‐film‐based electrochromic device

The dibenzyl derivative of poly(3,4‐propylenedioxythiophene) (PProDOT‐Bz₂) thin film is deposited onto ITO‐coated glass substrate by electropolymerization technique. The electropolymerization of ProDOT‐Bz₂ is carried out by a three‐electrode electrochemical cell. The cyclic voltammogram shows the redox properties of electrochemically prepared films deposited at different scan rates. The thin films prepared were characterized for its morphological properties to study the homogeniety. Classic six‐layer structure of PProDOT‐Bz₂ electrochromic device using this material was fabricated and reported for the first and its characterizations such as spectroelectrochemical, switching kinetics, and chronoamperometric studies are performed. The color contrast of the thin film and the device achieved are 64 and 40%, respectively, at λ_max (628 nm). The switching time is recorded and the observed values are 5 s from the coloring state to the bleaching state and vice versa. The chronoamperometry shows that the device performed up to 400 cycles, and it is capable of working up to 35 cycles without any degradation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40717.     

Electrical properties and the role of inhomogeneities at the polyvinyl alcohol/n‐inp schottky barrier interface

In this work, we have investigated the electrical properties of Au/n‐InP contacts with a thin layer of polyvinyl alcohol (PVA) as an interlayer. The current–voltage (I–V) and capacitance–voltage (C–V) measurements are carried out in the temperature range of 175–425 K. The Au/PVA/n‐InP Schottky structure show nonideal behaviors and indicates the presence of a nonuniform distribution of interface states. The temperature dependent interface states densities (N_SS), ideality factor and barrier height are obtained. An abnormal decrease in zero‐bias barrier height (BH) and increase in the ideality factor ( ) with decreasing temperature have been explained on the basis of the thermionic emission theory with Gaussian distribution (GD) of the BHs due to the BH inhomogeneities. The experimental I–V characteristics of Au/PVA/n‐InP Schottky diode has revealed the existence of a double GD with mean BH values of ( ) of 1.246 and 0.899 eV and standard deviation ( ) of 0.176 and 0.137 V, respectively. Consequently, the modified conventional activation energy versus plot gives and Richardson constants ( ) and the values are 1.17 and 0.71 eV and 9.9 and 6.9 A/cm² K², respectively, without using the temperature coefficient of the BH. The effective Richardson constant value of 9.9 A/cm² K² is very close to the theoretical value of 9.4 A/cm² K² for n‐InP. The discrepancy between Schottky barrier heights estimated from I–V and C–V measurements is also discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39773.     

Direct‐current and alternating‐current analysis of the humidity‐sensing properties of nickel oxide doped polypyrrole encapsulated in mesoporous silica SBA‐15

Nickel oxide (NiO) doped polypyrrole (PPy) was encapsulated in mesoporous SBA‐15. All of the synthesized samples were characterized by infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. They were investigated as humidity‐sensor materials at room temperature. The sensor showed excellent humidity sensitivity in the relative humidity range 11–95%. The humidity‐sensing properties were very much improved by encapsulation of the NiO‐doped PPy into mesoporous silica SBA‐15. Finally, the sensitivity mechanism was investigated by direct‐current (dc) and alternating‐current (ac) analysis. The dc circuit with the instantaneous polarity reversion method was designed by us to study the dc response in different humidity environments. The conductive mechanism was established through the dc and ac investigation, and the conductive particles were identified as ions and electrons. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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.     

Synthesis and characterization of a conducting polyaniline/TiO2−SiO2 composites

Polyaniline/TiO₂?SiO₂ composites were prepared by an in situ chemical oxidation polymerization approach in the presence of hybrid TiO₂?SiO₂ fillers. The obtained polyaniline/TiO₂?SiO₂ composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR), X‐ray diffraction (XRD), thermogravimetry (TG), and current?voltage (I?V) measurements. SEM picture shows a variation in morphology of polyaniline (PANI) from fiber shape to relatively regular particle shape with increasing TiO₂?SiO₂ contents in the composites. The floccule‐like structures were observed by high resolution TEM, which may help improve the efficiency of conductive network. SEM, XRD, TG, and FTIR spectra all reveal that a relatively strong interaction exist between TiO₂?SiO₂ and PANI. The I?V characteristics in such composites indicate that the charge transport is mainly governed by the space charge effects, which occurs at the interface between the conducting PANI and TiO₂?SiO₂. Meanwhile, PANI/TiO₂?SiO₂ composites exhibit significant increase in conductivity than PANI/TiO₂ or PANI/SiO₂. The reasons about high conductivity of PANI/TiO₂?SiO₂ have also been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2288–2295, 2013     

Electrochemical stability of PEDOT for wearable on-skin application

Conducting polymers are promising candidates for wearable devices due to mechanical flexibility combined with electroactivity. While electrochemical measurements have been adopted as a central transduction method in many on-skin sensors, less studied is the stability of the active materials (in particular poly3,4-ethylenedioxythiophene, PEDOT) in such systems, particularly for “on-skin” applications. In this study, several different variants of doped PEDOT are fabricated and characterized in terms of their (electrical, physical, and chemical) stability in biological fluid. PEDOT doped with tosylate (TOS) or polystyrenesulfonate (PSS) are selected as prototypical forms of conducting polymers. These are compared with a new variant of PEDOT co-doped with both TOS and PSS. Artificial interstitial fluid (aISF) loaded with 1% wt/vol bovine serum albumin is adopted as the testing medium to demonstrate the stability in dermal applications (i.e., conducting polymer microneedles or coatings on microneedles). A range of techniques such as cyclic voltammetry and electrochemical impedance spectroscopy are used to qualify and quantify the stability of the doped conducting polymers. Furthermore, this study is extended by using human skin lysate in the aISF to demonstrate proof-of-concept for stable use of PEDOT in wearable “on-skin” electronics.     

Preparation and electrochemical performance of modified Ti3C2Tx/polypyrrole composites

MXenes with a large surface area have been widely studied to improve the pseudocapacitance of electrode materials by combining conductive polymer materials. In this article, a superficial strategy to enhance the electrochemical properties by in situ polymerization of a pyrrole monomer between the Ti₃C₂T_x layers modified with 1,5-naphthalene disulfonic acid (NA) and cetyltrimethylammonium bromide (CTAB) was investigated. It is found that polypyrrole (PPy) and Ti₃C₂T_x can be combined through strong interactions between each other, and the specific capacitance of the modified Ti₃C₂T_x/PPy composite was increased to a maximum value of 437 F g⁻¹, which was more than thrice higher than that of pure PPy. The composite also exhibited good cycling performance (76% capacitance retention after 1000 cycles). Moreover, owing to the synergistic effect between the PPy and Ti₃C₂T_x layers, the composite provided better electron or ion transfer and surface redox processes than that of pure PPy, which indicated that this composite can be used as a promising electrode material for supercapacitors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47003.