Plasma-polymerized polyaniline films: Synthesis and characterization

The radio-frequency plasma polymerization technique was used to polymerize aniline onto polymer substrates including perfluorinated ethylene propylene copolymer. The plasma-polyaniline films were characterized by ultraviolet/visible absorption spectroscopy, Fourier transform infrared spectroscopy, electron spin resonance, X-ray photoelectron spectroscopy, scanning electron microscopy, and contact angle measurements. Preliminary conductivity measurements were also carried out. It was demonstrated that the chemical and physical characteristics of the plasma-polymerized poly-aniline films changed significantly with discharge conditions, indicating the possibility for tailoring the structure and properties of the polyaniline films by optimizing the discharge conditions. In particular, the contents of quinoid sequences and aliphatic crosslinking moieties were found to increase with increasing power input and/or discharge duration. By contrast, the number of free radicals trapped in the polyaniline films and their mobility were shown to increase with decreasing the power input and/or discharge duration within the plasma conditions covered in this study. Furthermore, a correlation was found between surface hydrophilicity of the resultant plasma-polyaniline films and the atomic ratio of C to N. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 633–643, 1998     

Synthesis of polyaniline and application in the design of formulations of conductive paints

Polyaniline (PANI) is prepared by chemical polymerization of aniline in acidic medium using ammonium peroxydisulfate ((NH₄)₂S₂O₈) as oxidant. The polymer, with a conductivity of 25–30 S/cm, is used to formulate conducting paints. A stable paint with a conductivity of 10^?3 S/cm is obtained. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis,characterization, and morphology of p‐toluene sulfonic acid‐doped polyaniline: A material for humidity sensing application

Polyaniline (PANI) doped with p‐toluene sulfonic acid was synthesized by chemical polymerization method using (NH₄)₂S₂O₈ as an oxidizing agent. This is a single step polymerization process for the direct synthesis of the conducting emeraldine salt (ES) phase, without the need of doping, dedoping, and redoping of the polymer. Presence of a free carrier tail at higher wavelength, characteristic of extended coil conformation along with a sharp polaronic peak is observed in the UV–vis spectrum of doped PANI in m‐cresol solvent. FT‐IR studies show the characteristic peaks of ES phase along with a sharp peak at 1120 cm^?1 representing vibration band of the dopant ion. Clumps of small fibers resulting in a sponge‐like structure was observed under scanning electron microscope. Thermal studies revealed a three‐step decomposition pattern. Conductivity is found to increase with an increase in the temperature showing “thermal activation behavior.” Decrease in resistance with increasing humidity is observed in a broad range of humidity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2161–2169, 2005     

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 N‐substituted polyaniline with mesogen molecules

The N‐substituted polyaniline (PANi) was synthesized by incorporation of bromine‐terminated mesogens onto the emeraldine form of polyaniline. Firsty three liquid crystalline molecules containing biphenyl units were synthesized. These mesogenic molecules are named as: 6‐bromo‐ (4‐hexyloxy‐biphenyl‐4′‐oxy) hexane (C₆? C₆Br), 5‐bromo‐(4‐hexyloxy‐biphenyl‐4′‐oxy) pentane (C₆? C₅Br), 6‐bromo‐(4‐octyloxy‐biphenyl‐4′‐oxy) hexane (C₈? C₆Br). Differential scanning calorimetry (DSC) in combination with polarizing optical microscopy (POM) were used to investigate the thermal properties of them. Optical microscopy showed focal conic texture characteristic of the Smectic A phase for (C₆? C₅Br) and (C₈? C₆Br). For (C₆? C₆? Br) smectic phase was determined. DSC experiments were also found in accord with mesophase formation. For the synthesis of N‐substituted polyaniline with these mesogen molecules, the emeraldine base polyaniline was reacted with BuLi to produce the N‐anionic polyaniline and then deprotonated polyaniline was reacted with bromine‐end mesogen to prepare mesogen‐substituted polyaniline through N‐substitution reaction. The degree of N‐substitution can be controlled by adjusting the molar feed ratio of mesogen to the number of repeat units of PANi. The microstructure and compositions of obtained polymers were characterized by FT‐IR, elemental analysis, DSC, and scanning electron microscopy (SEM). The cyclicvoltammetry show that the electroactivity of N‐substituted polyaniline is strongly dependent on the degree of N‐grafting. The solubility of mesogen‐substituted polyaniline in common organic solvents such as THF and chloroform was improved by increasing the degree of N‐substitution and also the samples are partially soluble in xylene. Liquid crystalline behavior of mesogen‐substituted polyanilines was investigated via POM, but no mesophase was observed. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and characterization of aluminum–polyaniline thin films and membranes

Polyaniline (PAni) films of different intrinsic oxidation states, including emeraldine salt, emeraldine base and leucoemeraldine base, were synthesized. Free‐standing membranes and thin film bilayers of aluminum–polyaniline were fabricated by magnetron sputter deposition of aluminum onto polyaniline films. Aluminum–polyaniline samples were analyzed by transmission electron microscopy (TEM) to investigate the microstructures of specimens, including cross‐sectional TEM micrographs of the metal‐polyaniline interfacial structure not previously reported in the literature. Auger electron spectroscopy (AES) and X‐ray photoelectron spectroscopy (XPS) were employed to study the chemical bonding and interaction between deposited aluminum and polyaniline at the interface. Results indicated that the intrinsic oxidation state of the polyaniline influenced the chemistry of the aluminum–polyaniline interface. Distinct interaction between aluminum and polyaniline in the emeraldine salt‐form was observed. However, there was no evidence of direct interactions of the aluminum with emeraldine base and leucoemeraldine base polyaniline. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and characterization of polyaniline/graphite conducting nanocomposites

A new method for the synthesis of exfoliated graphite and polyaniline (PANI)/graphite nanocomposites was developed. Exfoliated graphite nanosheets were prepared through the microwave irradiation and sonication of synthesized expandable graphite. The nanocomposites were fabricated via the in situ polymerization of the monomer at the presence of graphite nanosheets. The as-synthesized graphite nanosheets and PANI/graphite nanocomposite materials were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis (TGA). The conductivity of the PANI/graphite nanocomposites was dramatically increased over that of pure PANI. TGA indicated that the incorporation of graphite greatly improved the thermal stability of PANI. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1972–1978, 2004     

Synthesis,spectroscopic characterization and catalytic activity of cis-dioxidomolybdenum (VI) complexes with chiral tetradentate Schiff bases

New chiral mononuclear cis-dioxidomolybdenum (VI) complexes, MoO ₂ L ¹ –MoO ₂ L ¹⁰ , with tetradentate Schiff bases derived from various substituted salicylaldehydes and 1S,2S-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol were synthesized. All complexes were characterized by elemental analysis, circular dichroism, electronic and IR spectroscopy. ¹H NMR and also two-dimensional (COSY, NOESY and gHSQC) NMR measurements made for MoO ₂ L ¹ –MoO ₂ L ¹⁰ complexes show that Schiff bases are coordinated to the MoO₂²⁺ cation, creating facial (fac) and meridional (mer) types of geometrical isomers. Moreover, catalytic activity studies were also performed for all complexes in asymmetric sulfoxidation of thioanisole and epoxidation of styrene, cyclohexene and two monoterpenes, i.e. S(−)-limonene and (−)-α-pinene, using aqueous 30% H₂O₂ or tert-butyl hydroperoxide as the oxygen source.     

Synthesis and characterization of single‐wall‐carbon‐nanotube‐doped emeraldine salt and base polyaniline nanocomposites

Nanocomposites of polyaniline (PANI) and single‐wall carbon nanotubes (SWNTs) were prepared and characterized via resonance Raman and electronic absorption spectroscopy (ultraviolet–visible/near‐infrared). The chemical synthesis of PANI was performed in the presence of SWNTs in concentrations ranging from 10 to 50 wt % (SWNT/PANI). The obtained materials were hydrophilic, homogeneous composite compounds. The chemical interaction between PANI (in the conducting emeraldine salt form and in the insulating emeraldine base form) and metallic and semiconducting nanotubes was investigated. The emeraldine salt form of the polymer was significantly stabilized in the composite in comparison with plain PANI. A selective electronic interaction process between PANI and metallic SWNTs was found. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 815–822, 2005     

Sustainable chitosan/starch composite material for stabilization of palladium nanoparticles: Synthesis,characterization and investigation of catalytic behaviour of Pd@chitosan/starch nanocomposite in Suzuki–Miyaura reaction

We fabricated a green chitosan/starch composite as support material for stabilization of palladium nanoparticles for the first time. The chemical structure of the sustainable palladium nanocomposite was investigated using various techniques. Characterization studies showed that the average dimensions of the palladium nanocomposite ranged between 16 and 21 nm. The synthesized palladium nanocomposite was employed in the synthesis of a series of biphenyl compounds via Suzuki–Miyaura cross‐coupling reactions with an unconventional technique. All coupling reactions were conducted in very short reaction time and excellent biphenyl yields were obtained in the presence of the nanocomposite. The palladium catalyst was tolerant to a wide range of functional groups. We also investigated the recyclability and reusability of the palladium nanocomposite, and found that it could be used for seven successive cycles.     

Synthesis and characterization of epoxidized polybutadiene/polyaniline graft conducting copolymer

In this article the synthesis and characterization of an elastomeric conducting material, obtained by grafting polyaniline (EB) on commercial cis‐1,4‐polybutadiene (PB), are described. PB was first partially epoxidized in chloroform solution using meta‐chloroperbenzoic acid (MCPBA). The conducting polymer was then grafted to the activated polybutadiene (EPB) via the aminolysis reaction between the polyaniline NH₂ terminal groups and the oxirane rings. The material so obtained (EPBPAN) and the epoxidized intermediate product were characterized by ¹H NMR, ¹³C NMR, Fourier transform infrared, and ultraviolet–visible spectroscopy, thermal and mechanical analysis, and electrical conductivity measurements. The effect of the sample deformation on conductivity also was analyzed. The HCl doping of the EPBPAN film induced crosslinking reactions, generated by the acid cleavage of unreacted oxirane groups. The electrical conductivity of the doped material reached values of about 10^?5 Ω^?1 cm^?1. The key characteristics of our elastomeric conducting material are its simple synthesis, its starting as a commercial product, and the solubility of its undoped form in a common low‐boiling organic solvent like chloroform. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3082–3090, 2004     

二茂铁柠檬酰腙缩聚物的合成、表征及应用

通过1,1’-二乙酰基二茂铁与柠檬酸三甲酰肼缩合,制成了二茂铁柠檬酰腙聚合物(Fc-NM),再在DMF中与金属(M=Cu、Co、Ni、Mn、Zn)醋酸盐配位,制成五种二茂铁酒石酰腙金属配位聚合物(Fc-NM-M)。用IR、TGA、XRD、SEM及介电常数进行表征,结果表明,在适于移动通信应用的0.2-2.0GHz频段,Fc-NM有较高的介电常数(ε‘),较低的介电损耗(ε″),将其制成倒F型微带天线有良好的缩波性能,方向图及较高的增益。因此Fc-NM作为一种天线新材料,可用于小型化、多功能化及高增益的双频微带天线。     

Synthesis,characterization, and hoping transport properties of HCl doped conducting biopolymer‐co‐polyaniline zwitterion hybrids

A series of electrically conductive zwitterion hybrid materials were facilely synthesized with anionic acacia gum (AG) and cationic HCl doped polyaniline (PANI) through radical copolymerization method. A representative acacia gum‐polyaniline hybrid (AG‐PANI) was characterized using UV‐vis, FTIR, ¹H NMR, and SEM. HCl doped AG‐PANI possesses zwitterion character due to the presence of NH on PANI and ? COO^? of AG. The cyclic voltammogram of AG‐PANI showed three anodic peaks at 0.20 V, 0.58 V, and 0.64 V along with two cathodic peaks at 0.50 V and 0.40 V with large capacitive background currents. AG‐PANI exhibited electrical conductivity that was found dependent on the ratio of aniline to AG, temperature, and pH. Its electrical conductivity versus temperature plot indicated Mott's nearest‐neighbor hopping mechanism at the temperature range 83–323 K. The hybridization of AG and PANI yielded eco‐friendly advanced functional materials for technological applications. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and characterization of pentaerythritol-derived oligoglycol and their application to catalytic Wittig-type reactions

Several pentaerythritol-derived oligoglycols 1 with free hydroxyl groups are readily prepared by a convergent approach. Quantitative (13)C NMR proves to be an efficient tool for the characterization of oligoglycols. The corresponding telluride of oligoglycol 17 is synthesized and used as a good catalyst for Wittig-type reactions in preparing both disubstituted and trisubstituted olefins in good to high yields.     

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     

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.     

Nanorods of manganese oxides: Synthesis, characterization and catalytic application

Single-crystalline nanorods of β-MnO₂, α-Mn₂O₃ and Mn₃O₄ were successfully synthesized via the heat-treatment of γ-MnOOH nanorods, which were prepared through a hydrothermal method in advance. The calcination process of γ-MnOOH nanorods was studied with the help of Thermogravimetric analysis and X-ray powder diffraction. When the calcinations were conducted in air from 250 to 1050 °C, the precursor γ-MnOOH was first changed to β-MnO₂, then to α-Mn₂O₃ and finally to Mn₃O₄. When calcined in N₂ atmosphere, γ-MnOOH was directly converted into Mn₃O₄ at as low as 500 °C. Transmission electron microscopy (TEM) and high-resolution TEM were also used to characterize the products. The obtained manganese oxides maintain the one-dimensional morphology similar to the precursor γ-MnOOH nanorods. Further experiments show that the as-prepared manganese oxide nanorods have catalytic effect on the oxidation and decomposition of the methylene blue (MB) dye with H₂O₂.     

Au‐dimercaprol functionalized cellulose aerogel: Synthesis,characterization and catalytic application

A new derivative of cellulose aerogel was prepared via functionalization of cellulose with dimercaprol. Dimercaprol, as a chelating agent of Au(III), was applied for the loading of Au(III) on cellulose aerogel. The new organogold compound after characterization was used as an efficient heterogeneous catalyst in the oxidation reactions of aliphatic alcohols, benzyl alcohol, and ethylbenzene. Excellent selectivities and good conversions were obtained in the green oxidation reactions of alcohols and ethylbenzene. The high porosity of cellulose aerogel led to the good conversions with the low catalyst amounts. The significance of the presented work is the introducing of an environmentally benign process for the oxidation reactions based on a biocompatible catalyst.     

Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production

Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.     

Synthesis and electrical–magnetic properties of polyaniline composites

Composites of polyaniline (PANI) with both conducting and ferromagnetic feature were synthesized by an improved method proposed by the authors. The electrical and ferromagnetic properties of the composites were measured as a function of the concentration of KOH solution used during polymerization. The conductivity of the composites at room temperature decreases with the increase of the concentration of KOH; the maximum conductivity of 8.0 × 10⁻¹ S/cm can be obtained when 25 wt % of concentration of KOH was used. For a high concentration of KOH, ferromagnetic properties of the composites including a high saturated magnetization (∼ 10.0 emu/g) depending on the concentration of KOH solution and a lower coercive force (H_c ≈ 0) independent of the concentration of KOH solution were observed. It has been demonstrated that magnetic particles (Fe₃O₄) with nanometer size in the composites can be attributed to the ferromagnetic properties of the composites observed. For a lower concentration of KOH solution, on the other hand, the magnetic properties of the composites can be decomposed to Curie susceptibility χ_c depending on the temperature and Pauli susceptibility χ_P independent of the temperature. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2799–2805, 1998