Co-doped Polyaniline Research Articles

Low temperature double transition charge transport mechanism in co-doped polyaniline nanocomposites

Low temperature double transition charge transport mechanism in co-doped polyaniline nanocomposites

Co-doped polyaniline composites for biological application: Morphological, functional, optical and antibacterial activities

In the present work, we have successfully synthesized co-doped polyaniline (PANI) composites with various organic acids DBSA, phthalic acid, oxalic acid and Calotropis proceralatex using a simple chemical oxidative polymerization method. The structural, optical, surface morphology and antibacterial analyses were carried out for the synthesized PANI (DBSA-Phthalic acid), PANI (DBSA-Oxalic acid) and PANI (DBSA-C.Procera latex) composites. The structural characterization using XRD and FT-IR measurements confirmed the formation of emeraldine salt form of PANI from the observed characteristic peaks of PANI in all the composites. The observed UV–visible absorption and PL emission peaks also assured the synthesis of PANI in emeraldine form. SEM micrographs of PANI (DBSA-phthalic acid) composites exhibited continuous rock-like agglomerated structure. The antibacterial activity tested against medically important bacteria Bacillus subtilisrevealed a maximum inhibition zone for the DBSA-phthalic acid doped PANI composites when compared with other composites. The average value of zone of inhibition for the PANI composites is found to be 21–24 nm. The minimum inhibitory concentration (MIC) is found to be 1 mg/L for all the PANI composites whereas the minimum bactericidal concentration (MBC) is found to be 60 mg/L for PANI (DBSA-Phthalic acid) and 80 mg/L for PANI (DBSA-Oxalic acid), PANI (DBSA-C.Procera latex) composites. A larger and clear zone of inhibition exhibited by the synthesized co-doped PANI composites confirms their potential as an effective antibacterial agent.

Long-life P-type co-doped polyaniline cathodes for ultrahigh-energy-density aqueous zinc-ion batteries

Conductive polyaniline (PANI) is considered as a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its reversible redox properties. In this study, we prepared a binder-free PANI (βPG-PANI-6) cathode co-doped with β-naphthalene sulfonic acid (β-NSA), HClO4, and graphitic acid (GA) via a layer-by-layer self-assembled electro-polymerization method. As a soft template, β-NSA micelles can be doped with HClO4 into PANI nanoparticles to prevent the tight accumulation of PANI chains. Moreover, β-NSA and GA adsorbed on the surface of PANI nanoparticles through layer-by-layer self-assembly contain abundant weak acid groups, which can act as internal proton reservoirs to offer protons to guarantee high redox activity. During the electro-polymerization process, the flexible GA matrix which forms NO bond closely with PANI can alleviate the volume expansion effect of PANI. As a result, the βPG-PANI-6 cathode can obtain superior discharge specific capacity (560.5 mAh/g, 0.2 A/g), excellent rate performance (251.3 mAh/g, 10 A/g). It is commendable that the AZIBs assembled by βPG-PANI-6 cathode deliver ultra-high energy density and power density (535.31 Wh/kg @ 187.16 W/kg, 184.45 Wh/kg @ 7378.01 W/kg). This study expands the doping chemistry of PANI and advances the development of conducting polymer for AZIBs to a new level.

Fabrication and characterization of Ti/polyaniline-Co/PbO2–Co for efficient electrochemical degradation of cephalexin in secondary effluents

The traditional interlayer of PbO2 electrode possessed many problems, such as short service lifetime and limited specific surface area. Herein, a novel and efficient Ti/polyaniline-Co/PbO2–Co electrode was conctructed employing cyclic voltammetry to introduce a Co-doped polyaniline interlayer and anodic electrodeposition to synthetize a β-PbO2-Co active layer. Compared with pristine PbO2 electrode, Ti/polyaniline-Co/PbO2–Co exhibited more compact crystalline shape and higher active sites amounts. Pratically, the electrochemical degradation of 5 mg L−1 cephalexin in real secondary effluents was effectively achieved by the novel anode with 87.42% cephalexin removal and 71.8% COD mineralization after 120 min of 15 mA cm−2 electrolysis. The hydroxyl radical production and electrochemical stability were increased by 3.16 and 3.27 times respectively. The cephalexin degradation pathway was investigated by combining a density functional theory-based theoretical approach and LC-QTrap-MS/MS. The most likely cleavage point of the β-lactam ring was the O=C–N bond, whose attack would produce small molecular compounds containing the thiazole and 4, 6-thiazine rings. Further oxidation produced inorganic ions; quantitative investigations indicated the amino groups to undergo decomposition to form aqueous NH4+, which was further oxidized to NO3−. The accumulation of NO3− and SO42−, combined with a decrease in toxicity toward Escherichia coli, demonstrated the efficient mineralization of cephalexin on the Ti/polyaniline-Co/PbO2–Co electrode.

Multi-components matching construction of α-[SiW11Mn(H2O)O39]6-/biacid co-doped polyaniline wrapped interstice skeletal NiCo2O4 for high-performance electromagnetic wave absorption

A highly effective electromagnetic wave absorber with great tunability of absorption strength and bandwidth, in which polyoxometalate anion α-[SiW11Mn(H2O)O39]6- and heteropoly acid cation/HCl co-doped polyaniline wrapped interstice skeletal NiCo2O4 (ISNiCo2O4@BCDPANI/α-[SiW11Mn(H2O)O39]6- nanocomposites), was successfully prepared via a facile hydrothermal combined with supramolecular self-assembled method. The biacid co-doped polyaniline as the conductance loss phase was anchored on the high aspect ratio ISNiCo2O4 surface, making the whole material have certain electrical conductivity and reduce the percolation value. The other components were acted as the dielectric loss phase to equilibrate impedance matching. Meanwhile, the design of interstice skeletal structure effectively decreased the density and equivalent permittivity. The electromagnetic parameters were availably controlled by the hierarchical structure, thus improving the absorbing ability of nanocomposites. The magnetic loss provided by ISNiCo2O4 was derived from the eddy current and natural resonance. We compared the absorption properties of different as-prepared unitary to ternary products, matrix additions and component contents, and found some meaningful conclusions. The maximum RL value of ISNiCo2O4@BCDPANI/α-[SiW11Mn(H2O)O39]6- nanocomposites reached −52.4 dB with a thickness of only 1.6 mm, and the effective absorption bandwidth exceeding −10 dB was up to 6.5 GHz at only 1.9 mm. In contrast, as the conductance component content increased, the ternary nanocomposites showed better overall performance, but the thickness enlarged slightly, which the maximum absorption of −60.4 dB at 2.4 mm, an effective absorption bandwidth of 6.5 GHz at 2.9 mm, and bandwidth below −10 dB and −20 dB remarkably of 13.9 GHz and 11.1 GHz with the thickness range of 1.5–5 mm.

Submicrometric Fibrillar Structures of Codoped Polyaniline Obtained by Co-oxidation Using the NaClO/Ammonium Peroxydisulfate System: Synthesis and Characterization

A mixture of ammonium peroxydisulfate and sodium hypochlorite (NaClO) (co-oxidating system) were used to obtain polyaniline (PANi) doped with HCl and camphorsulfonic acid (CSA) (co-doping). The effect of HCl/CSA ratio added during polymerization on structure, morphology and electrical conductivity of the conducting polymer was investigated. When NaClO is used, the polymerization rate is substantially increased and the morphology changes from micrometric granular to nanometric fibrillar. CSA was used as complementary dopant but also to improve the solubility of PANi in common solvents. However, results suggest that quinone-like heterocycles containing carbonyl radicals as well as phenazine-type aromatic rings might be impeding an efficient doping in detriment of the conductivity.

Crystal Structure and Property of Proton Acid and Polypeptide Co-doped Polyaniline

An approach was presented in this article for organizing the polyaniline (PANI) nanoparticles using polypeptide as the template. PANIs were chemically synthesized in different weight ratios of poly(d-Glu-d-Lys) (PDGDL)/aniline (Ani) (mg/g) in the feed, doped acid, and polymerization time. Scanning electron microscopy and X-ray diffraction analysis showed that the PDGDL dictated the organization of the PANI nanoparticles. The formation and shape of PANI crystal structures were strongly affected by the parameters including weight ratio of PDGDL/Ani, doped acid, and polymerization time. Fourier transform infrared and UV–vis near-infrared spectrometry confirmed the strong interaction between PDGDLs and PANIs. Semiconductor parameter analyzer test showed that the conductivity of proton acid and polypeptide co-doped PANIs increased with the increase of the weight ratio of PDGDL/Ani and increased with the polymerization time extended from 12 to 60 h, but decreased from 60 to 72 h. Solubility test indicated that ...

Combination of cathodic reduction with adsorption for accelerated removal of Cr(VI) through reticulated vitreous carbon electrodes modified with sulfuric acid–glycine co-doped polyaniline

Improving the reduction kinetics is crucial in the electroreduction process of Cr(VI). In this study, we developed a novel adsorption–electroreduction system for accelerated removal of Cr(VI) by employing reticulated vitreous carbon electrode modified with sulfuric acid–glycine co-doped polyaniline (RVC/PANI-SA-GLY). Firstly, response surface methodology confirmed the optimum polymerization condition of co-doped polyaniline for modifying electrodes (Aniline, sulfuric acid and glycine, respectively, of 0.2mol/L, 0.85mol/L, 0.93mol/L) when untraditional dopant glycine was added. Subsequently, RVC/PANI-SA-GLY showed higher Cr(VI) removal percentages in electroreduction experiments over RVC electrode modified with sulfuric acid doped polyaniline (RVC/PANI-SA) and bare RVC electrode. In contrast to RVC/PANI-SA, the improvement by RVC/PANI-SA-GLY was more significant and especially obvious at more negative potential, lower initial Cr(VI) concentration, relatively less acidic solution and higher current densities, best achieving 7.84% higher removal efficiency with entire Cr(VI) eliminated after 900s. Current efficiencies were likewise enhanced by RVC/PANI-SA-GLY under quite negative potentials. Fourier transform infrared (FTIR) and energy dispersive spectrometer (EDS) analysis revealed a possible adsorption–reduction mechanism of RVC/PANI-SA-GLY, which greatly contributed to the faster reduction kinetics and was probably relative to the absorption between protonated amine groups of glycine and HCrO4−. Eventually, the stability of RVC/PANI-SA-GLY was proven relatively satisfactory.

Fe/Co/C–N nanocatalysts for oxygen reduction reaction synthesized by directly pyrolyzing Fe/Co-doped polyaniline

Development of precious metal-free catalysts for oxygen reduction reaction (ORR) is of great significance for the practical application of fuel cells. In this article, we report the finding that the C–N composites containing Fe and/or Co (C–PANI, Fe/C–PANI, Co/C–PANI, and FeCo/C–PANI), produced by directly pyrolyzing the Fe- and/or Co-doped polyaniline (PANI) precursors, show efficient electroactivity for ORR both in acidic and in alkaline media. Among the prepared catalysts, Fe/C–PANI and Co/C–PANI present the most positive ORR onset potential that is 0.61 V (vs. SCE) in 0.5 mol L−1 H2SO4 solution or −0.1 V (vs. SCE) in 1 mol L−1 NaOH solution. In addition, the Fe/C–PANI catalyst shows the largest limiting-diffusion current density for ORR both in acidic and in alkaline media. A four-electron reaction of ORR on the Fe/C–PANI and Co/C–PANI catalysts is more dominant than a two-electron reaction. Fe/C–PANI catalyst also presents good electrocatalytic activity stability for ORR both in acidic and in alkaline media.

Supercapacitor based on H+ and Ni2+ co-doped polyaniline–MWCNTs nanocomposite: synthesis and electrochemical characterization

In the search for promising electrode materials for supercomputer applications, we have synthesized a Ni2+ doped polyaniline, and a nanocomposite based on multiwalled carbon nanotubes (MWCNTs) and a Ni2+ doped polyaniline (PANI) in a HCl medium by an in situ oxidative polymerization. In the HCl medium and in the presence of Ni2+, PANI becomes co-doped with both H+ and Ni2+. The as synthesized materials were characterized by FTIR and Raman spectroscopy and an XRD study. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses confirmed the successful coating of the co-doped PANI on the MWCNT surface. The electrochemical characterizations were carried out by a three electrode system, with 1 M H2SO4 as the electrolyte. The PANI co-doped with H+ and Ni2+exhibited a specific capacitance of 311 F g−1 at a 0.5 A g−1 constant current, which was higher than that of the solely H+ doped PANI, which exhibited a specific capacitance of 265 F g−1 under the same conditions. The incorporation of MWCNTs to the co-doped PANI influenced the specific capacitance to increase to 781 F g−1 at the same constant current density, with a 92% retention of initial specific capacitance over 700 galvanostatic cycles.

Synthesis and Properties of Conducting Polyaniline by Co-Doping with Sulfosalicylic Acid and Sulfate Acid

A chemical oxidative polymerization of aniline sulfosalicylic acid (ANISSA) and aniline sulfate acid (ANIH2SO4) was performed in an aqueous solution. A co-doped polyaniline (PANI) was thus obtained, a higher conductivity than the insoluble H2SO4-doped PANI compressed pellet, and much higher conductivity than that prepared from pure ANISSA. The PANI doped with SSA and H2SO4 was characterized using Fourier-transform infrared spectra (FTIR), Fourier-transform Raman spectra (FT-Raman), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The investigation reveals that SSA and H2SO4 as dopant not only enhances crystallinity of polyaniline but also stability of polyaniline.

Thermal degradation mechanism of dodecylbenzene sulfonic acid- hydrochloric acid co-doped polyaniline

Co-doped polyaniline (PANI) was synthesized in microemulsion by hydrochloric acid (HCl) and dodecylbenzene sulfonate (SDBS) then thermal treated in air at 160 and 200 °C for 0.5 h, respectively. The changes of structure, thermal stability, micromorphology and electrical conductivity after thermal treatment were studied by Fourier transformed infrared (FT-IR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and four-probe technique. It was found that the conductivity of PANI decreased about 50% after thermal treated at 160 °C, and droped by 2 orders of magnitude at 200 °C. This may be explained by that only a fraction of total mass of HCl losses during thermal treatment at 160 °C, but after heating at 200 °C, the dedoping of dodecylbenzene sulfonic acid (DBSA) along with cross-linking, chain scission and oxygen incorporation in a form of carbonyl groups take place, resulting in destruction of crystal structure, decrease of the emeraldine sequence, lower thermal stability and heterogeneous micromorphology.

Soluble polyaniline co-doped with dodecyl benzene sulfonic acid and hydrochloric acid

A chemical oxidative polymerization of aniline dodecyl benzenesulfonic acid (ANIDBSA) and aniline hydrochloric acid (ANIHCl) was performed in an aqueous solution because the former monomer stimulates the solubility and the latter the conductive structure of the synthesized polymer. A co-doped polyaniline (PANI) was thus obtained, which is soluble in common organic solvents such as chloroform, and exhibits, without any additional doping, a higher conductivity than the insoluble HCl-doped PANI compressed pellet, and much higher conductivity than that prepared from pure ANIDBSA. The PANI doped with DBSA and HCl was characterized using FTIR, EDX and UV spectroscopies. At an ANIHCl/ANIDBSA molar ratio in the feed of 3:7 and no additional HCl, the polymer exhibited a maximum conductivity of 7.9 S/cm and a maximum yield of 30.8%. If additional HCl was introduced, the conductivity could reach a value as high as 14 S/cm.

Polyaniline co-doped with camphor sulfonic and hydrochloric acids by chemical oxidation in aqueous solution

A co-doped polyaniline was prepared from aniline camphorsulfonate (ANICSA) and aniline hydrochloride (ANIHCl), which was soluble in common organic solvents, such as m-cresol. Without any additional doping, it possessed a higher conductivity (2 S/cm) than those prepared from ANICSA or ANIHCl alone (0.4 S/cm). In other words, a synergistic effect arose through the chemical oxidative polymerization of a mixture of ANICSA and ANIHCl. The mole ratio of (CSA + HCl)/aniline was 1; if additional HCl was introduced, the conductivity reached a value as high as 7.9 S/cm. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 80–85, 2001