Electrochemical synthesis of polypyrrole/polyimide conducting composite using a polyamic acid precursor

Conducting polymer/poly(amic acid) composites were synthesized by casting poly(amic acid) (PAAc)film onto the surface of stainless steel followed by electrochemical deposition of polypyrrole. Polypyrrole/polyimide (PPy/PI) composites were also formed by preimidizing the polyamic acid film prior to electrodeposition of PPy. The electrical resistance of the bottom side of PPy/PAAc composite (2.3 Ω cm) was lower than that of the PPy/PI composite (6.4 Ω cm), the thickness of the matrix was the same. A PI matrix was used for electropolymerization of pyrrole. The electrodeposition was investigated by using different current densities. IR spectroscopy revealed interactions between the PAAc and PPy in the composite.     

First conducting polymer functionalized with covalently linked carborane units

The anodic oxidation of a carborane-substituted pyrrole leads to the formation of an electroactive polymer film (σ∼10⁻¹ S cm⁻¹) which shows a strongly increased overoxidation resistance in comparison with unsubstituted polypyrrole.     

The development of conductive composite surfaces by a diffusion-limited in situ polymerization of pyrrole in sulfonated polystyrene ionomers

Electrically conductive composite surfaces were prepared by a diffusion-controlled in situ polymerization of pyrrole in the surface layer of sulfonated polystyrene ionomer films. Premolded films of the ionomer sulfonic acid derivatives were sequentially immersed in aqueous solutions of pyrrole and FeCl₃, and polymerization occurred only where both the monomer and the oxidant were present. The penetration of the polypyrrole (PPy) into the film was controlled by varying the immersion time in the monomer solution. The amount of PPy produced depended on the immersion time of the film in the monomer and the degree of sulfonation of the ionomer. Surface conductivities of 10⁻⁴-10⁻¹ S/cm were achieved with PPy concentrations from 2 to 22 wt % and composite layers as thin as 15 μm. Intermolecular interactions occurred between PPy and the ionomer by proton transfer. Incorporation of PPy also increased the tensile strength of the ionomer film, significantly increased its modulus above T_g, and inhibited melt flow. © 1997 John Wiley & Sons, Inc.     

电化学合成吡咯与己内酰胺导电共聚物

采用恒电位方法实现了吡咯与己内酰胺在导电玻璃电极上的直接电化学共聚,聚合反应在含有0.1mol/L吡咯和1.5 mol/L己内酰胺的硝基甲烷电解质溶液中进行,外加电位控制在1.2 V以上.聚合产物中聚吡咯与聚己内酰胺链段的组成可通过调节合成电位加以控制.共聚物的形貌、结构与性质采用扫描电子显微镜、热重分析、红外光谱等手...     

Preparation of Conducting Composite Materials Based on Polymer Nanofibers and Polypyrrole

Conducting materials based on polypyrrole-modified nanofibers of polylactides of different molecular masses and copolymers of ε-caprolactam (–NH–(CH₂)₅–CO–) and hexamethylenediamine adipate (–H(CH₂)₆NHCO(CH₂)₄CO–) were prepared. As shown by scanning electron microscopy, oxidative polymerization of pyrrole on the polymer nanofiber matrix depends on the nanofib er hydrophilicity. The heterophase synthesis of polypyrrole on the surface of hydrophilic nanofibers of the aliphatic copolyamide allowed uniform coating of the material surface with polypyrrole nanoparticles. The surface resistivity of the composite material was about 0.4 kΩ sq^–1.     

Microstructural and Potential Dependence Studies of Urease-Immobilized Gold Nanoparticles–Polypyrrole Composite Film for Urea Detection

Gold nanoparticle–polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)–PPy/ITO-glass bioelectrode for urea detection in Tris–HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm^?2 charge densities, respectively, was studied towards the urea concentration in Tris–HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm^?2 charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm^?2 charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade.     

Conducting Redoxpolymer-Based Reagentless Biosensors Using Modified PQQ-Dependent Glucose Dehydrogenase

Reagentless, oxygen-independent glucose biosensors based on an Os-complex-modified polypyrrole matrix and on soluble PQQ-dependent glucose dehydrogenase from Acinetobacter calcoaceticus are described.As the soluble form of glucose dehydrogenase from Acinetobacter calcoaceticus is a hydrophilic enzyme with a positive net charge, its entrapment into the positively charged hydrophobic polypyrrole film is much more complicated than that of the corresponding membrane enzyme or the negatively charged and very stable glucose oxidase. Possible ways for using soluble PQQ-dependent glucose dehydrogenase in combination with conducting polymer films are seen in the modulation of the enzyme properties by covalent binding of suitable compounds to the protein shell together with the adjustment of the properties of the conducting polymer film. This can be done by neutralising the net charge of the protein and/or optimising the electron-transfer pathway between enzyme and electrode surface by covalent binding of suitable redox relays to the protein surface.In addition, methods for increasing the hydrophilicity of the polymer film, such as the co-entrapment of high-molecular weight hydrophilic additives and copolymerisation of hydrophilic pyrrole derivatives are presented. It is demonstrated that the replacement of the parent monomer pyrrole by a suitable hydrophilic pyrrole derivative facilitates the entrapment of the modified soluble PQQ-dependent glucose dehydrogenase into the Os-complex-modified polymer and hence allows for the development of reagentless biosensors.     

磺化聚苯乙烯／聚吡咯复合膜

磺化聚苯乙烯（ＳＰＳ）／聚吡咯（ＰＰｙ）复合膜是通过毗咯单体在ＳＰＳ基体中原位聚合方法制成的．用ＦＴＩＲ研究ＳＰＳ／ＰＰｙ复合膜分子间的相互作用，特别是ＳＰＳ中ＳＯ３阴离子在１２００ｃｍ－１不对称伸缩振动港带的分裂，说明了聚吡咯是以阳离子的形式作用于ＳＰＳ中ＳＯ３阴离子上，产生强的离子－离子相互作用．同时还研究了在复合过程中，引起ＳＰＳ基体的微区结构与性能的变化．ＳＰＳ由于吡咯单体的胀入和聚合，导致了ＳＰＳ微相分离，复合膜在动态力学性能测试中出现了两个Ｔｇ转变，分别在１２４和１４５℃．     

Conductive Composite Materials of Polyethylene and Polypyrrole with High Modulus and High Strength

Composite films of polyethylene (PE) and polypyrrole (PPy) were prepared by polymerization of PPy on an ultradrawn polyethylene film with high modulus and high strength in ferric chloride (FeCl₃) aqueous solution. The electrical conductivity of the composite film was found to be related to the polymerization conditions, such as polymerization temperature, polymerization time, the concentration and the oxidation potential of the FeCl₃ solution. Scanning electron microscopy, FTIR and ¹³C NMR spectra were used to elucidate the morphological and structural variations of PPy prepared under different conditions, which lead to the differences in the electrical properties of the resultant composite films. The best electrical conductivity of the composite was about 5.5 S/cm for the film prepared under optimum conditions. The Young's modulus and the tensile strength reached 80 GPa and 3.2 GPa, respectively, which indicated the successful production of a conductive polymer with high strength and high modulus.     

吡咯在一些聚合物基质中聚合生成导电高分子复合物的研究

用电化学氧化聚合方法将吡咯在聚氨酯(PU)、聚已内酰胺(Nylon 6)、聚芳砜酰胺(PSu)及聚对苯二甲酰对苯二胺(PPTA)等绝缘聚合物中聚合生成聚吡咯(PP_y)的高分子复合物PU/PP_y、Nylon 6/PP_y、PS_u/PP_y、PPTA/PP_y等。它们具有良好的电导率及力学性能、报导了他们的制备方法及电导率、力学性能、电化学活性、扫描电镜、X-射线衍射的表征。     

Coordinated organogel templated fabrication of silver/polypyrrole composite nanowires

A new method to fabricate metal/conducting polymer composite nanowires is presented by taking silver/polypyrrole composite nanowires as an example.A silver(Ⅰ)-coordinated organogel as template was prepared firstly,and redox-polymerization of pyrrole took place on the gel fiber,giving product of silver/polypyrrole nanowires.The silver/polypyrrole nanowires were characterized by multiple techniques.This strategy could be carried out in one-step procedure at room temperature,and it proves the utility of coordinated organogels in template synthesis of polymer nanostructures.     

Investigation of SPR and electrochemical detection of antigen with polypyrrole functionalized by biotinylated single-chain antibody: A review

An electrochemical label-free immunosensor based on a biotinylated single-chain variable fragment (Sc-Fv) antibody immobilized on copolypyrrole film is described. An efficient immunosensor device formed by immobilization of a biotinylated single-chain antibody on an electropolymerized copolymer film of polypyrrole using biotin/streptavidin system has been demonstrated for the first time. The response of the biosensor toward antigen detection was monitored by surface plasmon resonance (SPR) and electrochemical analysis of the polypyrrole response by differential pulse voltammetry (DPV). The composition of the copolymer formed from a mixture of pyrrole (py) as spacer and a pyrrole bearing a N-hydroxyphthalimidyl ester group on its 3-position (pyNHP), acting as agent linker for biomolecule immobilization, was optimized for an efficient immunosensor device. The ratio of py:pyNHP for copolymer formation was studied with respect to the antibody immobilization and antigen detection. SPR was employed to monitor in real time the electropolymerization process as well as the step-by-step construction of the biosensor. FT-IR demonstrates the chemical copolymer composition and the efficiency of the covalent attachment of biomolecules. The film morphology was analyzed by electron scanning microscopy (SEM).Results show that a well organized layer is obtained after Sc-Fv antibody immobilization thanks to the copolymer composition defined with optimized pyrrole and functionalized pyrrole leading to high and intense redox signal of the polypyrrole layer obtained by the DPV method. Detection of specific antigen was demonstrated by both SPR and DPV, and a low concentration of 1 pg mL⁻¹ was detected by measuring the variation of the redox signal of polypyrrole.     

Electrochemical copolymerization of pyrrole and 2,2-bithiophene and semiconducting characterization of the resulting copolymer films by electrochemical impedance spectroscopy and photoelectrochemistry

The electrochemical copolymerization of pyrrole and bithiophene was studied at a polymerization potential of 1.1 V for various monomer ratios. The cyclic voltammograms showed that the electrochemical properties of the resulting copolymer films changed gradually from those of polypyrrole to polybithiophene with an increase in concentration of bithiophene in the initial electrolyte. The evidence for copolymer formation is based on the analytical results of electrospray ionization mass spectroscopy, thermoanalysis, and Raman spectroscopy. The results showed that cooligomers and homooligomers were found in the electrolyte after copolymerization. The difference between the morphology of a copolymer of pyrrole and bithiophene and a polymer mixture of polypyrrole and polythiophene was demonstrated by scanning electron microscopy. Electrochemical impedance and photocurrent measurements were carried out in order to achieve information on the semiconducting properties of the homopolymers and copolymers obtained. A model of a very thin layer of polypyrrole formed immediately on the electrode surface covered by a thicker copolymer film was developed to explain the results.Dedicated to Zbigniew Galus on the occasion of his 70^th birthday.     

Molecular Dynamics Simulations of the Orientation and Reorientational Dynamics of Water and Polypyrrole Rings as a Function of the Oxidation State of the Polymer

Summary: Polypyrrole is one of the most widely‐studied conducting polymers due to its steady electrochemical response and good chemical stability in different solvents, including organic and inorganic ones. In this work, we provide for the first time valuable information in atomic detail concerning the steady and dynamic properties of pyrrole rings as a function of the oxidation state of the polymer. The study was carried out by Classical molecular dynamics simulation, where the system was modelled by 256 polypyrrole chains of 10 pyrrole rings each. Water was explicitly introduced in our simulations. Besides the uncharged or reduced state, two steady oxidation states of the polymer have been simulated by introducing a net charge (+1) on 85 and 256 of the polypyrrole chains. To balance the charges emerging in these oxidised states, 85 and 256 chloride ions (Cl⁻¹) respectively, were introduced into the system. From an analysis of the simulated trajectories, the orientation and relaxation times of water and pyrrole rings were evaluated for the different oxidation states of the polymer across the polypyrrole/water interface. The calculated densities for different oxidation states describe the swelling or shrinking process during electrochemical oxidation or reduction respectively. The rotational relaxation times calculated for the polypyrrole rings decrease with increasing oxidation of the polymer, which is in a good agreement with experimental electrochemical data. Almost no variation in pyrrole ring orientation was measured for the different oxidation states of the polymer, even compared with polypyrrole bulk. As regards the water structure in the vicinity of the polypyrrole/water interface, both the orientation and orientation relaxation time were strongly affected by the presence of charges in the polymer. Thus, the water dipole was strongly orientated in the vicinity of the water/polypyrrole interface and its orientational relaxation time increased by one order of magnitude compared with bulk water, even when only one‐third of the total polymer chains were oxidised. The results attained in this work were validated with experimental results, when they were available.

Polypyrrole ring orientation and water orientation at the polypyrrole/water interface. (a) 256 rPPy and (b)171 rPPy + 85 oPPy.     

Preparation and characterization of electrostrictive polyurethane films with conductive polymer electrodes

All-polymer electrostrictive soft films were developed for the first time by depositing conductive polymer (polypyrrole) directly on both sides of solution-cast electrostrictive polyurethane elastomer films. The final composite films are flexible with strong adhesion between the polyurethane film and the conductive polymer electrode. The conductivity (sheet resistivity ∼1000 Ω/□), of the polymer electrode is appropriate for its intended use. The compatible interface between the polypyrrole electrode polymer and the electrostrictive polyurethane significantly improves the acoustic and optical transparency of these composite films, compared with using a metal electrode film. The all-polymer films also exhibit comparable dielectric properties to gold-electroded polyurethane films in the temperature range from −40^°C to +80^°C. The temperature range covers the soft segment glass transition temperature of the polyurethane elastomers, which is about −20^°C. The films also show large electric field induced strain responses which are dependent on film thickness and measurement frequency. The electrostrictive characteristics in the all-polymer films show similarities to those of the films with gold electrodes under identical measurement conditions. © 1998 John Wiley & Sons, Ltd.     

Incorporation of ferrocene into polypyrrole films via an ionic adduct with boron trifluoride

1-(Ferrocenyl)ethanol has been immobilized within polypyrrole films during their electrochemical deposition, or following their deposition, via its adduct with boron trifluoride. Dissociation of H⁺ from this adduct, formed in a solution of boron trifluoride diethyl ether (BFEE) in acetonitrile, produces an anion that can act as a counterion for oxidized polypyrrole. Its subsequent hydrolysis produces a polypyrrole film containing neutral 1-(ferrocenyl)ethanol which was found to be strongly retained. In addition to producing a novel type of polypyrrole–ferrocene composite, this work provides clear evidence to support the efficacy of this methodology for the incorporation of neutral species within conducting polymer films.     

Preparation and characterization of conducting poly(acryloyl chloride)‐g‐ polypyrrole copolymer

The electroactive copolymer of poly(acryloyl chloride) (PAC) and polypyrrole (PPy) can be synthesized by electrochemical polymerization using a polymer precursor which contains a pyrrole moiety in its side chain. Poly(acryloyl pyrrole) (PAP) was synthesized chemically with acryloyl chloride and potassium pyrrole salt and characterized using FT‐IR and ¹H‐NMR spectroscopy. PAP dissolved in dimethyl formamide (DMF), was spin‐coated on a platinum electrode and polymerized electrochemically in the electrolytic mixture solution consisting of acetonitrile, 0.1 M pyrrole, and 0.1 M lithium perchlorate. Constant potential electrolysis showed that pyrrole groups in the precursor were oxidized to form PPy, that is, they acted as grafting centers at which the PPy grew. Scanning electron microscopy (SEM) results and conductivity measurements supported the formation of the graft copolymer. The morphological feature of PAC‐g‐PPy copolymer films showed homogeneous structure, but that of PAC/PPy composite films showed irregular structure. The maximum conductivity of the final products was about 1 S/cm. Copyright © 2002 John Wiley & Sons, Ltd.     

Novel preparation of electrically conducting poly (vinyl chloride) by photo-dehydrochlorination from poly (vinyl chloride)/polypyrrole composite film

Polypyrrole (PPy) was deposited electrochemically on a platinum plate from a nitric acid solution of pyrrole. The PVC/PPy composite film was finally obtained by casting poly(vinyl chloride) (PVC) onto the PPy electrode from a tetrahydrofuran solution of PVC. The prepared composite film was irradiated at 90°C with a low-pressure mercury lamp in the stream of hydrogen gas saturated with steam, and the PVC film was dehydrochlorinated, leading to the formation of conjugated polyene. The electrical conductivity (σ) of the PVC film in the irradiated composite film was reveled: σ=2.51 × 10^?5S cm^?1. By iodine doping, σ was further enhanced up to 5.04 X 10^?3 S cm^?1. The tensile strength of the irradiated composite film became larger than that of the original PVC film; i.e., the stress at break was: 461 (composite film); 401 kg cm^?2 (PVC). These results were brought about by the doping of radical species to the conjugated polyene. The anion, NO^?₃, doped during the electrodeposition of PPy was photodecomposed to generate radical NO₂ and this species was doped to the polyene, resulting in the formation of electrically conductive PVC and mechanically improved composite film. © 1994 John Wiley & Sons, Inc.     

Synthesis of electrically conductive polypyrrole-polystyrene composites using supercritical carbon dioxide: I. Effects of the blending conditions

The electrical conductivity for a polymer composite consisting of polypyrrole (PPy) and an insulating host polystyrene (PS) is reported in this study. The host polymer was blended with pyrrole monomer using either supercritical carbon dioxide (SCCO₂) or high-pressure liquid carbon dioxide (HPLCO₂) as the carrying solvent. After the blending process, the blended host polymer was soaked in an oxidant solution. This process is compared with that of oxidant impregnation. With the same processing conditions, a polymer composite with much higher conductivity was obtained when the blending process was carried out before doping in an oxidant agent. Scanning electron microscope (SEM) and elemental analysis reveal that polymerization proceeded when the blended host polymer was soaking in the oxidant solution. It is observed that SCCO₂ provides better conditions for blending the host polymer with pyrrole monomer than HPLCO₂ at the same density. The maximum conductivity of the polymer composites also increases with temperature and pressure at the same SCCO₂ density.     

蒽醌/聚吡咯复合膜修饰电极的电化学行为和电催化活性

在水溶液中制备了掺杂蒽醌磺酸盐(AQS)的聚吡咯(PPy)/玻碳复合膜修饰电极,采用循环伏安法和旋转圆盘电极技术研究了该修饰电极在不同pH值溶液中的电化学行为以及在pH=5.5的磷酸盐缓冲溶液中对氧还原反应的电催化性能和动力学.结果表明,与裸玻碳电极相比,PPy膜的存在不仅降低了AQS的反应电位和峰电位差,而且增大了其氧化还原反应的峰电流,H2AQ/HAQ-氧化还原对的电离常数为9.5.AQS/PPy膜修饰电极上氧的还原主要是两电子还原为H2O2的不可逆过程,H2AQ对氧还原反应起主要催化作用,还原过程符合异相氧化还原催化机理.该修饰电极具有良好的电化学重现性.