盐酸掺杂聚苯胺的制备及性能研究

本文用溶液聚合法制备盐酸掺杂聚苯胺,测定了体系酸度对聚苯胺电导率的影响,及盐酸掺杂聚苯胺在不同条件下经过热处理后的电导率,采用TGA、XRD等方法,研究了热处理过程对聚苯胺结构的影响。结果表明,当热处理温度为90℃时,电导率高于初始值,当热处理温度高于100℃时,电导率开始下降,到达220℃时,电导率下降了约4个数量级。在氮气中聚苯胺电导率的衰减比空气中小,聚苯胺经热处理后在浓硫酸中的溶解性会明显降低。本文还探讨了去掺杂、氧化和化学交联等盐酸掺杂聚苯胺的热降解机理。     

Synthesis and electrorheology of camphorsulfonic acid doped polyaniline suspensions

 Semiconducting camphorsulfonic acid doped polyaniline (PANI–CSA) particles were synthesized by chemical oxidation polymerization, and their chemical structure and particle size were examined via Fourier transform IR spectroscopy and scanning electron microscopy, respectively. Electrorheological (ER) fluids were prepared by dispersing the PANI–CSA particles in silicone oil, and their steady-shear rheological properties under electric fields were investigated using a rotational rheometer with a high-voltage generator. The PANI–CSA synthesized in this study possesses typical ER behavior:shear stress increases with increasing electric field strengths. Received: 31 August 2000 Accepted: 6 April 2001     

Synthesis and characterization of polyaniline doped with organic acids

Spectroscopic [UV–visible and Fourier transform IR (FTIR)] and thermal properties of chemically synthesized polyanilines are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid). The optical spectra show the presence of a greater fraction of fully oxidized insulating pernigraniline phase in polyaniline doped with acetic acid. In contrast, the selectivity in the formation of the conducting phase is higher in oxalic acid as a protonic acid media. The FTIR spectra of these polymers reveal a higher ratio of the relative intensities of the quinoid to benzenoid ring modes in acetic acid doped polyaniline. Scanning electron micrographs revealed a sponge‐like structure derived from the aggregation of the small granules in acetic acid and oxalic acid doped polyaniline. A three‐step decomposition pattern is observed in all the polymers, regardless of the protonic acid used for the doping. The second step loss related to the loss of dopant is found to be higher in the oxalic acid doped polymer. In accordance with these results the conductivity is also found to be higher in oxalic acid doped material. The temperature dependent conductivity measurements show the thermal activated behavior in all the polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2043–2049, 2004     

Synthesis and characterization of new azobenzenesulfonic acids doped conducting polyaniline

New azobenzene sulfonic acid dopants were synthesized by diazotized coupling reaction of sulphanilic acid diazonium salt with commercially available raw materials such as phenol, m-cresol and 4-phenylphenol. The structures of the dopants are confirmed by NMR and FT-IR. Polyaniline emeraldine base was doped by these new azobenzenesulfonic acid dopants in two different solvent medium such as methanol and N-methylpyrrolidinone to produce green emeraldine salt. The doping process was confirmed by FT-IR and UV-vis spectroscopy. The effect of composition of dopant on the conductivity of the polyaniline was investigated and the results suggest that the conductivity increases with the increase in the dopant concentration and attained maxima for more than 38% in the feed. The conductivity measurements reveal that all the dopants equally effective in producing in high conductivity in the range of 0.02 S/cm and the conductivity of the doped samples are insignificant to the structural difference in the dopant. WXRD and SEM analysis indicate that the doped samples are highly amorphous and porous in nature. The thermal analysis by TGA indicate that all the doped materials were highly stable up to 300 °C for high temperature applications.     

Synthesis and electrochemical behavior of polyaniline doped by electroactive anions

Electrochemical potentiodynamic and potentiostatic synthesis was used to obtain polyaniline (PANI) doped by new electroactive anions (EAAs): organic dianion of the diammonium salt of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfoacid) (ABTS) and inorganic ammonium hexachloroiridate dianion IrCl₆²⁻ (HCI). Two methods of electrochemical synthesis were studied: under constant potential (potentiostatic synthesis) and under potential cycling (potentiodynamic synthesis). The optimum ratio of EAA: principal electrolyte (1 M H₂SO₄) was found at which the maximum catalytic effect was obtained in the course of the synthesis and the principal properties of PANI obtained were preserved.     

Synthesis and characterization of polyaniline nanoparticles in phosphonic acid amphiphile aqueous micellar solutions for waterborne corrosion protection coatings

Polyaniline (PANI) dispersions consisting of 270 to 380 nm sized particles were prepared by oxidation with ammonium peroxydisulfate (APS) in n‐decylphosphonic acid (DPA) micellar solutions. The green dispersions do not undergo macroscopic precipitation for more than a year. The synthesized DPA doped PANI exhibited enhanced electrical conductivity (3.6 S cm^?1 ) compared with DPA‐PANI (2.3 x 10 ^{? 4} S cm ^{? 1}) prepared by postsynthesis treatment of the PANI‐base with DPA. It was shown that through protonation with decylphosphonic acid, polyaniline showed a significantly enhanced solubility in common organic solvents like chloroform, xylene, etc. The synthesized PANI was characterized by intrinsic viscosity, solubility, FT‐IR , conductivity, SEM , and TGA measurements. The wide‐angle X ‐ray diffraction study revealed the appearance of a peak located at low angles (d = 29.4 – 35.3 Å) suggesting the formation of layered structure of PANI backbone separated by long alkyl side chains of DPA. The anticorrosive performance of the bilayer coatings composed of a bottom layer of DPA doped polyaniline covered with a polyvinyl butyral topcoat, have been demonstrated for steel exposed to neutral saline solutions. It was found that the inhibitive properties of DPA dopant provides further protection to the base metal through smart release when damage is produced on the surface of the coating. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1606–1616     

Electropolymerized coatings of polyaniline on copper by using the galvanostatic method and their corrosion protection performance in HCl medium

The synthesis of polyaniline coatings on the copper (Cu) surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by Fourier transform infrared spectroscopy, UV–visible absorption spectrometry and scanning electron microscopy. The anticorrosion performances of polyaniline coatings were investigated in 0.5 M HCl medium by the potentiodynamic polarization technique and electrochemical impedance spectroscopy. The corrosion rate of polyaniline‐coated Cu was found to be ～27 times lower than bare Cu, and potential corrosion increased from ?0.21 V versus Ag/AgCl for uncoated Cu to ?0.19 V versus Ag/AgCl for polyaniline‐coated Cu electrodes. Electrochemical measurements indicate that polyaniline coating has good inhibiting properties with a mean efficiency of ~96% at 10 mAcm^?2 current density applied on Cu corrosion in acid media. The results of this study clearly ascertain that the polyaniline has an outstanding potential to protect Cu against corrosion in an acidic environment. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis and characterization of phosphorized polyaniline doped with phytic acid and its anticorrosion properties for Mg-Li alloy

A phosphorized polyaniline (PANI) doped with phytic acid (PhA) was synthesized by the chemical oxide method with PhA as a dopant and applied to improve the anticorrosion properties of magnesium-lithium (Mg-Li) alloys after blending with eco-friendly silane sol. The chemical structures and morphologies of PANI samples were evaluated by FTIR spectroscopy, UV-Vis-NIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). All characterizations indicate that the as-synthesized phosphorized PANI (PANI-PhA) exists in doped emeraldine salt state with net-like structures crosslinked by phosphate carboxyl groups. The conductivity and thermostability of PANI-PhA were better than those of PANI doped with phosphoric acid (PANI-H₃PO₄) and undoped PANI. The anticorrosion properties of PANI/silane sol composite coatings for Mg-Li alloy were tested by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results prove that the anticorrosion ability of PANI-PhA is the best among the three PANI samples, as shown by a low corrosion current (1.28 × 10^?7 A·cm^?2) and high impedance (5.62 × 10⁶ Ω·cm²). The possible anticorrosion mechanism was proposed based on procedure analysis.     

Charge storage performance of doped carbons prepared from polyaniline for supercapacitors

Doped carbons have been prepared from polyaniline for supercapacitors. The morphology of samples has been characterized by scanning electron microscope, the surface chemical composition of samples has been investigated by X-ray photoelectron spectroscopy, and the surface area of samples has been calculated by Brunauer–Emmett–Teller measurement. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol L⁻¹ potassium hydroxide. Their charge storage performance has been evaluated, and the effect of nitrogen atomic functionalities on the pseudocapacitive property has been studied. The experimental results have proved two mechanisms of energy storage in doped carbons: double-layer formation and pseudocapacitance. The overall specific capacitance of doped unactivated carbon is mainly attributed to pseudocapacitance, that of doped activated carbon prepared by physical activation is attributed to the synergic effect of pseudocapacitance and double-layer capacitance, but that of doped activated carbon prepared by chemical activation is mainly attributed to double-layer capacitance.     

Synthesis,characterization and properties of polyaniline doped with transition metal substituted silicotungstate

Polyaniline hybrid material doped with transition metal mono-substituted silicotungstate β₂-K₆[SiW₁₁M(H₂O)O₃₉]?·?xH₂O (M?=?Mn²⁺, Co²⁺, Cu²⁺, Fe²⁺) were prepared for the first time. Their scanning electron microscopy (SEM), infrared (IR), UV–Vis, and X-ray diffraction (XRD) patterns confirm the existence of Keggin anions and form the space reticular structure. The material exhibits excellent proton conduction, its proton conductivity is 9?×?10^?2?s?cm^?1 at room temperature (20°C).     

Synthesis and properties of polyaniline doped with iron-substituted silicotungstate isomers with Keggin structure

Four polyaniline hybrid materials doped with iron-substituted silicotungstate isomers α,?β _i - K_5?n H _n [SiW₁₁Fe(H₂O)O₃₉]?·?xH₂O (β_i?=?β₁, β₂, β₃) were prepared. The materials were characterized by elemental analysis, IR spectra, UV-Vis spectra, scanning electron microscopy (SEM), TG-DTA and X-ray diffraction (XRD). The conductivity and fluorescence were determined and thermal stability was studied. The UV-Vis, IR and XRD results confirm the existence of Keggin anions. Thermal analysis indicates that SiW₁₁Fe/PANI has better thermal stability. The images of scanning electron microscopy (SEM) show that the materials are microporous. The materials exhibit excellent proton conductivity of 8.5?×?10^?2?S?cm^?1 at room temperature (20°C). The spectral data indicate that polyaniline doped with α, β_i-SiW₁₁Fe have similar fluorescence, λ_em?=?418–470?nm, and emit blue light.     

Synthesis of nitrogen doped activated carbon/polyaniline material for CO2 adsorption

The equilibrium adsorption isotherms of carbon dioxide and nitrogen on the nitrogen doped activated carbon (NAC) prepared by the chemical activation of a pine cone‐based char/polyaniline composite were measured using a volumetric technique. CO₂ and N₂ adsorption experiments were done at three different temperatures (298, 308, and 318 K) and pressures up to 16 bar, and correlated with the Langmuir, Freundlich, and Sips models. The Sips isotherm model presented the best fit to the experimental data. The N‐doped adsorbent showed CO₂ and N₂ adsorption capacity of 3.96 mmol·g⁻¹ and 0.86 mmol·g⁻¹, respectively, at 298 K and 1 bar. The selectivity predicted by ideal adsorbed solution theory (IAST) model was achieved 47.17 for NAC at 1 bar and y_N2 = 0.85 which is a composition similar to flue gas. The results showed that NAC adsorbent has a high CO₂‐over‐N₂ selectivity in a binary mixture. The relatively fast sorption rate of CO₂ on NAC compared to N₂ indicates the stronger affinity between CO₂ and amine groups. The isosteric heat of adsorption of CO₂ by the NAC demonstrated the physico‐chemical adsorption of CO₂ on the adsorbent surface. These data showed that prepared NAC could be successfully applied in separation of CO₂ from N₂.     

Synthesis and electrochemical performance of sandwich-like polyaniline/graphene composite nanosheets

Sandwich-like polyaniline/graphene composite nanosheets have been synthesized by chemical oxidation polymerization of aniline monomer on the surfaces of reduced graphene oxide nanosheets in the absence of any surfactants. The influences of the mass ratios of aniline and reduced graphene oxide on the sizes and morphologies of polyaniline/graphene nanocomposites have been investigated. As the mass ratio of aniline and reduced graphene oxide is smaller than 12:1, polymerization reaction of aniline occurs on the surfaces of reduced graphene oxide by heterogeneous nucleation to form sandwich-like polyaniline/graphene composite nanosheets. However, besides sandwich-like polyaniline/graphene composite nanosheets, polyaniline nanofibers are formed by homogeneous nucleation. In comparison with reduced graphene oxide and polyaniline nanofibers, the obtained sandwich-like polyaniline/graphene composite nanosheets exhibit good electrochemical performances due to the synergistic effect between graphene and polyaniline.     

Conducting polyaniline/nano-zinc phosphate composite as a pigment for corrosion protection of low-carbon steel

Zinc phosphate (Zn₃(PO₄)₂) nanocrystals were synthesized and used for making conducting polyaniline/nano-zinc phosphate composite by chemical oxidative method. The product was characterized by UV–visible absorption spectroscopy. The crystal structure, morphology and thermal stability of the product were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermo gravimetric analysis, respectively. The epoxy-based paint containing conducting polyaniline/nano-zinc phosphate composite pigment was applied on low-carbon steel samples. Corrosion protection performance of the painted low-carbon steel samples in 3.5 mass % sodium chloride solution was evaluated using electrochemical technique. Transmission electron microscopic image revealed the formation of core shell structure of the composite. Composite was found to be more thermally stable than the conducting polyaniline. The corrosion rate of conducting polyaniline/nano-zinc phosphate-painted low-carbon steel was found to be 5.1 × 10^?4 mm per year, about 34 times lower than that of unpainted low-carbon steel and 10 times lower than that of epoxy nano-zinc phosphate paint-coated steel. The study reveals the possibility of using conducting polyaniline/nano-zinc phosphate as a pigment for corrosion protection.     

Synthesis and characterization of sol–gel derived glass-ceramic and its corrosion protection on 316L SS

Glass-ceramic was prepared by sol–gel method using Ca(NO₃)₂·4H₂O and P₂O₅ as Ca and P precursors, respectively. In order to improve the bioactivity of the implant material, glass-ceramic (β-Ca₂P₂O₇) coating was developed on 316L SS substrate by spin coating method. Coating was annealed at different temperatures and its corrosion resistance was evaluated by electrochemical polarization and impedance analysis using Ringer’s solution as electrolyte. The results from the present study, show excellent corrosion resistance for coated 316L SS, corroborated by the high values of charge transfer resistance from impedance analysis and higher breakdown and repassivation potential with the corresponding lower current density from polarization measurements. Based on the results, the glass-ceramic coating on 316L SS can be considered as a corrosion resistant material.     

Enhanced the performance of zinc strontium sulfide-based supercapattery device with the polyaniline doped activated carbon

Journal of Solid State Electrochemistry - A hybrid supercapacitor, also known as a supercapattery, combines the high power density of supercapacitors with the high energy density of batteries. In...     

Improving corrosion protection performance of polypyrrole coating by tungstate ion dopants

Polypyrrole (PPy) and polypyrrole-tungstate (PPy-WO ₄ ²⁻ ) coatings were electrodeposited on mild steel (MS) electrodes by cyclic voltammetry (CV) technique. Aqueous oxalic acid solution was used as supporting electrolyte for these processes. For the electrodeposition of PPy-WO ₄ ²⁻ , tungstate anion was added to the supporting electrolyte. The surface morphologies of the two types of coated-samples were characterized by scanning electron microscopy (SEM) and line-scan EDX analysis. Furthermore, open circuit potential (OCP) monitoring, polarization and electrochemical impedance spectroscopy methods were performed for comparing the corrosion protection performances. Corrosion studies indicate that WO ₄ ²⁻ dopants can improve corrosion protection properties by taking part in: (i) the passivation process occurred prior to electrodeposition process, (ii) the electrosynthesis process and incorporation into polymer chain. The text was submitted by the authors in English.     

Microtubules of polyaniline doped with HCl and HBF4

Microtubules of polyaniline (PANI) doped with HCl, HBF₄, and β-naphthalene sulfonic acid (NSA) were synthesized by an improved in situ doping polymerization method. Ultraviolet-visible spectra, scanning electron microscopy, ESR, and X-ray diffraction characterized the molecular structure of the resulting PANI microtubules. These microtubules had a diameter of 1 ∼ 10 μm and a conductivity at room temperature of 0.2 ∼ 3.5 S/cm, depending on the molecular structure and concentration of the dopant. The degree of crystallinity of the PANI microtubules was enhanced by increasing the molecular size of the dopant; that is, the order PANI-NSA > PANI-HBF₄ > PANI-HCl was observed in the crystallinity of the microtubules. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4605–4609, 1999     

Electrophysical properties of polyaniline doped with heteropoly acids

Composites of polyaniline with phosphotungstic and phosphomolybdic heteropoly acids of Keggin type were studied by impedance spectroscopy. Doping of polyaniline with these acids allows the proton conductivity of the polymer in the composites to be increased by six orders of magnitude.