Electrochemical study of the uranium exchange by polypyrrole‐based resins

Electrochemical control of the binding of uranium ions by redox active polypyrrole resins was studied. The experimental conditions for this binding were optimized with respect to the uranium ions to be fixed, the resin, and the solution. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3473–3484, 1999     

Preparation and characterization of composites of polyethylene with polypyrrole‐coated wollastonite

Composite sheets of polyethylene and polypyrrole‐coated wollastonite were prepared by extrusion and compression molding. Four compatibilizers were also evaluated, poly(ethylene‐co‐methyl acrylate) (EMA), maleated polyethylene (MAPE), poly(ethylene‐co‐vinyl alcohol) (EVOH), and poly(vinyl alcohol) (PVOH). The composite materials were characterized using X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy (SEM), Raman spectroscopy, and mechanical properties determined by tensile tests. SEM micrographs showed that significantly improved interactions occurred between the PE matrix and polypyrrole‐coated wollastonite particles in the presence of EMA, MAPE, and EVOH. Raman spectroscopy confirmed that the polypyrrole coating on the wollastonite particles was not thermally degraded during melt processing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical synthesis and characterization of poly(pyrrole‐co‐ε‐caprolactone) conducting copolymer

The direct electrochemical copolymerization of pyrrole (Py) and ε‐caprolactone at various monomer ratios was carried out by potentiostatic methods in nitromethane. Characterizations of the novel copolymer were based on scanning electron microscopy, differential scanning calorimetry, thermal gravimetrical analysis, cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared spectra, and elemental analysis studies. The results showed that the electrochemical oxidation of Py and ε‐caprolactone comonomers generated true copolymers rather than blends of the two homopolymers. The electrical conductivity of the copolymers increased with the amount of polypyrrole in the copolymer between the value of 8.2 S/cm and 0.6 S/cm. A probable mechanism of copolymerization was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of a porous conducting polymer film by electrochemical synthesis–solvent extraction method

Porous conducting polypyrrole (PPy) films have been obtained by electrochemical synthesis–solvent extraction method. The results of scanning electron microscopy (SEM) show that the size and the distribution of pores can be controlled during the electrochemical synthesis. The porous PPy films have sufficiently good mechanical properties, and electrochemical voltammetric studies imply that the porous films also have high electrical conductivity and good electrochemical reversibility. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 303–307, 2004     

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials. Synthesis and characterization

Polypyrrole–poly(heptamethylene p,p′-bibenzoate) conducting materials, PPy–P7MB/ClO₄, were obtained by anodic coupling of pyrrole into a polybibenzoate inert matrix, using perchlorate anions as dopant agent. P7MB is a main-chain liquid crystalline polybibenzoate with adequate mechanical properties and elastic modulus of 1.4GPa at room temperature. The method of synthesis, galvanostatic or potentiostatic electrodeposition, is responsible for differences in the PPy–P7MB/ClO₄ films electrochemical response. FTIR spectra show the complex structures of P7MB and the composite conducting material. The conductivity of PPy–P7MB/ClO₄ films maintains a relatively high value, σ = 13.74Scm^?1, in spite of the insulating effect of polybibenzoate. Film micrographs reveal the typical cauliflower morphology exhibited by polypyrrole and the evolution of film growth with time.     

Fourier transform infrared study of polypyrrole–poly(vinyl alcohol) conducting polymer composite films: Evidence of film formation and characterization

The electrochemical preparation of polypyrrole (PPY)–poly(vinyl alcohol) (PVA) conducting polymer composite films on an indium–tin oxide glass electrode from an aqueous solution containing a pyrrole monomer, a p‐toluene sulfonate electrolyte, and a PVA insulating polymer is reported. The prepared PPY–PVA composite films were characterized by Fourier Transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and conductivity measurements. The FTIR study showed that the composite of PPY and PVA formed through bond formation between PVA and the p‐toluene sulfonate dopant anion. The conductivity data of PPY–PVA showed that with increasing PVA concentration in the pyrrole solution, the conductivity of the prepared PPY–PVA film increased up to a certain level due to an increase in conjugation length, and later, it decreased with further increases in the PVA concentration in the solution due to a decrease in conjugation length. This was supported by the FTIR band intensity I₁₅₆₀/I₁₄₈₀. The TGA results show that the PPY–PVA polymer composite film was thermally more stable than the PPY film. A shielding effectiveness of 45.6 dB was exhibited by the PPY–PVA composite film in the microwave frequency range. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4107–4113, 2006     

Recovery of gold cyanide using inherently conducting polymers

Removal of gold from basic solutions containing [Au(CN)₂]^? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry     

Electrochemical studies of kerosene-pyrolysedcarbon films

Polycrystalline thin films of conducting carbon are deposited on alumina substrates by the pyrolysis of kerosene vapour at 1000C for 2h in argon atmosphere. Preliminary structural analysis is done by XRD, laser-Raman, FTIR and SEM studies. The electrochemical behaviour of as-grown conducting carbon films was investigated in various electrolytes at different pH and the performance was compared with that of platinum and glassy electrodes. The electrochemical window of the kerosene carbon electrode in 100mm H2SO4 was found to be 2.91V which is greater than that of glassy carbon (2.79V) and platinum (2.02V). Cyclic voltammetry reveals that Pt electrode has almost an equal tendency towards hydrogen and oxygen evolution, whereas glassy carbon favours hydrogen evolution and kerosene carbon favours oxygen evolution. It is suggested that the kerosene carbon electrode can be used as an oxygen electrode more efficiently. Unlike diamond films or glassy electrodes, kerosene carbon thin films are of low cost and good stability; they are also easy to grow on various ceramic substrates of any size. Moreover, these electrodes are very economical and promising for application in chlor-alkali industry.     

Electroless recovery of gold chloride using inherently conducting polymers

Conducting polymers deposited onto reticulated vitreous carbon (RVC) were shown to remove gold from aqueous solutions in a facile and highly efficient fashion. For acidic solutions with initial [AuCl₄]^? concentrations between 0.1 and 1000 ppm, gold recoveries >90% were obtained. Experiments, conducted using solutions containing 0.1 ppm [AuCl₄]^?, also demonstrated that the composite materials were significantly more effective at recovering gold than activated carbon. Gold removal from solutions containing [AuCl₄]^? and much higher concentrations of iron was highly selective. Copyright © 2004 Society of Chemical Industry     

Development of an electrochemical‐surface plasmon dual biosensor based on carboxylated conducting polymer thin films

A biosensing platform based on the covalent attachment of biomolecules on electropolymerized carboxylated conducting polymers, poly(3‐aminobenzoic acid) and poly(3‐pyrrole carboxylic acid), were developed for the selective simultaneous detection of two biomolecules using electrochemical‐surface plasmon resonance (EC–SPR) spectroscopy. The surface morphology of the developed biosensors was studied by scanning electron microscopy and atomic force microscopy. The EC–SPR dual biosensor was developed for the label‐free, simultaneous, and selective detection of glucose and human immunoglobulin G (IgG). A change in current density was clearly observed after the injection of glucose, whereas a change in SPR reflectivity was clearly observed after the injection of human IgG. The present work demonstrates the potential of this biosensing platform for real sample analysis in the future. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45641.     

Corrosion protection of iron by polystyrenesulfonate-doped polypyrrole films

Electropolymerized polypyrrole (PPy) has been studied as a protective coating for iron in NaCl 3% corrosive medium. The protection mechanism is of the galvanic type, and the main cause for the loss of protection is the progressive invasion of the film by chloride anions. To reduce exchanges between PPy counter-ions and chloride anions, a composite polyanions/PPy film was used. Polystyrenesulfonate was chosen as a large size counter-ion which could be trapped in the polymer matrix. Due to the negligible mobility of these anions, the film permselectivity changed from anionic to cationic. A significant improvement in PPy film protection efficiency was obtained.     

Conducting polymer blends of polypyrrole with polyvinyl acetate,polystyrene, and polyvinyl chloride based toxic gas sensors

Blends of the conducting polymer, polypyrrole (PPy), and in the insulating host polymers, polyvinyl acetate (PVAc), polystyrene (PS), and polyvinyl chloride (PVC) resin, have been prepared chemically. Threshold conductivities occur at about 5% for PPy in blends with host polymers. The characterizations of these blends were done by FTIR, UV‐visible, differential scanning calorimetric (DSC), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The products of the blends have electrical conductivity comparable to PPy and mechanical properties similar to hosting polymers. The response mechanism of the conducting blends to a selection of gases and vapors was investigated using two techniques, measurement of conductance and mass changes using a four‐point probe method, and a X‐ray fluorescence (XRF) device, respectively. These responses of blends to toxic gases and vapors are more well explained. Prepared films were exposed to hydrogen halides (HCl, HBr, and HI), hydrogen cyanide, halogens (Cl₂, Br₂, and I₂), monochloroacetic acid (MCAA), 1‐3‐5 trichloromethyl benzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA), and cyanogen bromide (CB). The changes of conductivity of polymers frequently observed are partly due to one stage in the two‐stage sorption, perhaps involving the swelling of the polymer, then diffusion gases into polymer chains. The swelling of polymers is a slow process, therefore, preswelled polymer films tend to decrease the response times of blends with respect to gases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 49–62, 2003     

Electrochemical polymerization of polypyrrole-heparin nanotubes: Kinetics and morphological properties

Electrically conductive polypyrrole (PPy) was functionalized with heparin (Hep) to improve its surface biocompatibility. Heparin, which is a bioactive polyelectrolyte, was used as the doping anion. The immobilization of Hep in PPy was facilitated by the use of a nanoporous membrane which acts as templating substrate. In this way we have synthesized nanostructured electrodes based on polypyrrole and heparin as hollow tubules. The aim of this study was to determine the influence of the electrosynthesis parameters (monomer concentration and electrolyte nature) on the morphology and kinetics of the PPy nanomaterials in view of their possible, long-term biomedical applications.     

Semitransparent,flexible electrochemical capacitors with excellent stability fabricated with polypyrrole–titanium mesh electrodes

Polypyrrole deposited on titanium mesh (PPy–TiM) was fabricated via a galvanostatic method with titanium mesh as the substrate to electrochemically deposit polypyrrole (PPy) doped with p‐toluene sulfonate anions. The influence of the deposition time on the characteristics of the PPy–TiM samples was investigated. Then, semitransparent flexible electrochemical capacitors were assembled with the optimal samples of PPy–TiM as electrodes and H₃PO₄–poly(vinyl alcohol) as the gel electrolyte. The testing results show that PPy in the optimal PPy–TiM electrode had a specific capacitance of about 326 F/g, and the capacitance of the assembled cells still remained unchanged or up even after 20,000 cycles. Just as expected, the cells possessed semitransparent and good flexibility, and three cells connected in series could drive an LED device. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2017     

Preparation electroactive film of (n‐pyrrolyl)1,1‐methane dihydroxamic acid and its derivative containing complexing cavities preformed by entwining ligands on metallic centers

The (N‐pyrrolyl)1,1‐methane dihydroxamic acid have been synthesized from its N‐substituted ester group derivative, then chemically polymerized in the presence of oxidants such as ammonium persulphate and Iron(III) perchlorate for hydroxamic acid and ester groups derivatives, respectively. This compound and its ester group derivative was successfully electropolymerized by a cyclic voltammetry method. New functionalized polypyrrole films containing transition metal complexes have been prepared and studied. The strategy is based on the three‐dimensional template effect of a metal center (Cu^II, Ni^II, Cr^III, Fe^III) able to entwine two and three end functionalized chelating ligand before or after polymerization. The used ligand consists of a methyl dihydroxamic acid bearing one pyrrole nuclei. The rigidity of the polymer matrix is sufficient to allow demetalation of the template center (by CN^? or SCN^?) without collapse of the three‐dimensional structure. Such property is related to the expected complex topology of the material prepared. The organic backbone certainly contains interlocking rings and various network substructures. The polymer matrix thus keeps a little memory of the templating metal used for building it. Fe(III) ion turned out to be the most convenient template during the polymer electrosynthesis and seemed to lead to the most structured network. The various complexes obtained using electrochemical synthesis method display electrochemical properties analogous to those of the corresponding catenate in solution. All complexes in low oxidation states are remarkably stabilized by the entwined and entangled system. The conductivity of these polymers and it metal complexes were measured using four‐probe method. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Dopant macroinitiator for electropolymerisation and functionalisation of conducting polymer thin films

Grafting of polymer brushes from conducting polymer (CP) thin films by controlled radical polymerisation provides a versatile route for the synthesis of functional, electroactive surfaces, with applications in diverse fields. However, one of the drawbacks of this approach is the difficulty of upscaling the synthesis due to the need for specialised CP precursor monomers functionalised with initiation sites. We herein describe an alternative approach to the synthesis of CP‐based polymer brushes whereby atom transfer radical polymerisation initiation sites are attached to a macrodopant incorporated into CP films during electropolymerisation. The facile electropolymerisation of commonly studied CPs with an initiator‐functionalised macrodopant – poly[(styrene sulfonate)‐co‐(2‐bromopropionyloxyethyl methacrylate)] – is demonstrated. The composite polymer films thus synthesised were used as substrates for grafting of hydrophilic polymer brushes. Although poly(styrene sulfonate) is commonly used as a macrodopant in CP films, its initiator‐functionalised derivatives have not previously been utilised in this manner. Despite the elegance of this approach, to the authors' knowledge, there have been no previous examples reported of utilising macromolecular dopants as initiators for subsequent grafting of polymer brushes. © 2017 Society of Chemical Industry     

9-(2'-硝基苯基)咔唑的电化学聚合及其表征

在含0.1 mol/L四氟化硼四丁基胺的二氯甲烷溶液中,直接阳极氧化9-(2'-硝基苯基)咔唑获得了高质量聚(9-(2'-硝基苯基)咔唑)膜.UV-Vis、FT-IR证明聚合物共轭长链的形成;FT-IR和量化计算确定单体在3,6位聚合;荧光光谱表明聚合物是一种蓝色荧光物质;热重分析表明硝基取代提高了聚咔唑的热稳定性.     

Photoluminescence,FTIR, and electrical characterization of samarium(III) chloride‐doped polyaniline

The synthesized polyaniline (PANI) is doped with different concentrations of Samarium(III) chloride (SmCl₃). The electrical conductivity of doped PANI samples has been measured in the temperature range (300–400K). It has been found that dc conductivity increases with the increase of dopant concentration. Different parameters, based on the conductivity, such as pre‐exponential factor (σ₀) and activation energy (ΔE) have also been calculated. These parameters exhibit information about the nature and suitability of the dopant. Doped samples are characterized by FTIR and photoluminescence studies, which show the interaction of dopant with PANI. Two sharp peaks of different intensities from PL spectra at 388 and 604nm have appeared in doped PANI, which might be due to the effect of SmCl₃. It has been observed that SmCl₃ (dopant) shows noticeable changes in the electrical and spectroscopic properties of doped PANI. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical,thermal, and microwave properties of conducting composites of polypyrrole/polypyrrole‐coated short nylon fibers with acrylonitrile butadiene rubber

Pyrrole was polymerized in the presence of anhydrous ferric chloride as oxidant and p‐toluene sulfonic acid as dopant. Polypyrrole‐coated short nylon fibers were prepared by polymerizing pyrrole in the presence of short nylon fibers. The resultant polypyrrole (PPy) and PPy‐coated nylon fiber (F‐PPy) were then used to prepare rubber composites based on acrylonitrile butadiene rubber (NBR). The cure pattern, direct current (DC) conductivity, mechanical properties, morphology, thermal degradation parameters, and microwave characteristics of the resulting composites were studied. PPy retarded the cure reaction while F‐PPy accelerated the cure reaction. Compared to PPy, F‐PPy was found to be more effective in enhancing the DC conductivity of NBR. The tensile strength and modulus values increased on adding PPy and F‐PPy to NBR, suggesting a reinforcement effect. Incorporation of PPy and F‐PPy improved the thermal stability of NBR. The absolute value of the dielectric permittivity, alternating current (AC) conductivity, and absorption coefficient of the conducting composites prepared were found to be much greater than the gum vulcanizate. PPy and F‐PPy were found to decrease the dielectric heating coefficient and skin depth significantly. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,characterizations, and physical properties of carbon nanotubes coated by conducting polypyrrole

A new type of carbon nanotube (CNT) (diameter of <100 nm) coated by conducting polypyrrole (PPY) was synthesized by in situ polymerization on CNTs. The structure of the resulting complex nanotubes (CNT‐PPY) was characterized by elemental analysis, X‐ray photoelectron spectroscopy, Raman spectra, and X‐ray diffraction. These indicated no significant chemical interaction between PPY and the CNT. The electrical, magnetic, and thermal properties of the complex nanotubes were measured and showed the physical properties of the CNTs were modified by conducting PPY. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2605–2610, 1999