Study on the Impedance Characteristic and Electrocatalytic Activity of Platinum‐Modified Polyaniline Film

The composite electrode of platinum‐modified polyaniline film is formed in 0.5 M H₂SO₄ + 3 mM H₂PtCl₆ solution by cyclic potential or constant potential deposition of platinum particles in polyaniline film. To make a comparison, the polyaniline film with the same initial thickness and structure is also treated with the cyclic potential or constant potential polarization in 0.5 M H₂SO₄ solution. The electrochemical impedance spectroscopy (EIS) of the composite electrode of platinum‐modified polyaniline film is studied in sulfuric acid solution and compared with the EIS of the polyaniline film without platinum dispersion. The results show that the different modes of potential polarization affect greatly the nature and distribution of the platinum particles, instead of the structure of the polyaniline film (matrix). The electrode reaction kinetics and mass transport process parameters involving charge transfer resistance (R_ct), double layer capacitance (C_dl), constant phase elements (CPE) and Warburg impedance in platinum substrate/platinum‐modified polyaniline film/solution interface are discussed on the basis of the interpretation of the characteristic impedance spectra and connected to the electrocatalytic activity on the oxidation of methanol molecules.     

Reversible encapsulation of nanometer-size polyaniline and polyaniline-Au-nanoparticle composite in starch

In this paper we report a new method of solubilization of polyaniline and polyaniline-Au-nanoparticle composite by encapsulating nanometer-size particles in starch. The solubilization was carried out in the presence of ultrasonic waves. We also report that the encapsulation was completely reversible and the dissolved polyaniline as well as the composite could be recovered by replacement with molecular iodine. In addition, the polymer particles could also replace molecular iodine from starch-iodine complex. UV-Visible and Fourier transform infrared (FTIR) spectroscopic measurements established the reversible nature of encapsulation. Transmission electron microscopic measurements showed that the sizes of the particles encapsulated in starch were on the order of 10-20 nm for both polyaniline and Au-nanoparticle-polyaniline composite particles. X-ray diffraction evidenced the presence ofAu-nanoparticles in the starch-polyaniline-Au-nanoparticle composite. Finally, we also mention here that the dissolved polyaniline could also be recovered as a precipitate by enzyme (diastage) hydrolysis of the polyaniline encapsulating starch.     

Electrorheological properties of suspensions of monodispersed micron‐sized polyaniline composite particles

Monodispersed micron‐sized polyaniline (PANi) composite particles were synthesized by chemically oxidative polymerization of aniline in the presence of functional porous polymer particles. The formation of the PANi‐coated composite particles was confirmed by scanning electron microscopy. Electrorheological (ER) properties of the monosized composite particle suspensions were then investigated under different DC electric fields by altering the particle characteristics. The ER effect of the PANi composite suspensions was largely dependent on the composition ratio (PANi loading), the particle conductivity, and the particle concentration. Dynamic oscillation measurements revealed that the applied electric field induced the viscoelastic property of the ER suspensions by generating the chain structures of the suspended particles. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1163–1170, 2002     

Platinum-modified polyaniline/polysulfone composite film electrodes and their electrocatalytic activity for methanol oxidation

The polyaniline/polysulfone (PAN/PSF) composite films were prepared by electropolymerization, and then platinum was deposited into this composite film to obtain the platinum-modified polyaniline/polysulfone(Pt/PAN/PSF) composite film electrodes. Their component, morphology and structure were characterized by FTIR spectra, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results show that the composite film has a bi-layer structure with asymmetrical pores, and the platinum particles are homogeneously dispersed in the modified film electrodes. The cyclic voltammetry and electrochemical impedance spectroscopy techniques were applied to investigate the electrochemical properties and the electrocatalytic activity of the modified film electrodes, which show a promotive action for methanol oxidation and the methanol oxidation under a diffusion-controlled process.     

The effect of zeolite on the curing of epoxy resin by polyaniline: a kinetic study

Polyaniline sulfate‐zeolite composite was prepared by emulsion polymerization. Epoxy resin was cured using polyaniline‐sulfate salt and various amounts of polyaniline sulfate‐zeolite composite. The kinetics of the cure reaction for an epoxy resin based on the diglycidyl ether of bisphenol A (DGEBA) with polyaniline‐sulfate and polyaniline sulfate‐zeolite composite have been studied using differential scanning calorimetry (DSC) under isothermal and dynamic conditions. Isothermal kinetics analysis was performed using the phenomenological model of Kamal. Dynamic kinetic analysis was performed using Kissinger's method. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis and characterization of polyaniline/silicon dioxide composites and preparation of conductive films

The focus of this study was to synthesize the inherently conductive polymer polyaniline using an optimized process to prepare polyaniline/silicon dioxide (PANI/SiO₂) composites by in situ polymerization and ex situ solution mixing. PANI and PANI/SiO₂ composite films were prepared by drop‐by‐drop and spin coating methods. The electrical conductivities of HCl doped PANI film and PANI/SiO₂ composite films were measured according to the standard four‐point‐probe technique. The composite films exhibited an increase in electrical conductivity over neat PANI. PANI and PANI/SiO₂ composites were also investigated by spectroscopic methods including UV‐Vis, FT‐IR, and Photoluminescence. UV‐Vis and FT‐IR studies showed that SiO₂ particles affect the quinoid units along the polymer backbone and indicate strong interactions between the SiO₂ particles and the quinoidal sites of PANI (doping effect). The photoluminescence properties of PANI and PANI/SiO₂ composites were studied and the PANI/SiO₂ composites showed increased intensity as compared to neat PANI. The increase of conductivity of PANI/SiO₂ composite may be partially due to the doping or impurity effect of SiO₂ where the silicon dioxides compete with chloride ions. The morphology of particles and films were examined by a scanning electron microscope (SEM). SEM measurements indicated that the SiO₂ were well dispersed and isolated in composite films. Copyright © 2009 John Wiley & Sons, Ltd.     

Layer-by-layer electrosynthesis of Pt–Polyaniline nanocomposites for the catalytic oxidation of methanol

A new composite material based on the electrochemical generation of a layer-by-layer structure of polyaniline (PANI) and Pt particles has been prepared. The number of layers and the nature of the external layer (PANI or Pt) determine the electrocatalytic performance of the composite for the oxidation of methanol. We demonstrate that the layer-by-layer approach to form the nanocomposite and modification of the Pt particles with a layer of PANI leads to substantially higher catalytic efficiency.     

用共混和共聚法改性聚苯胺及其电流变液的研究

通过共混和表面接枝共聚两种方法改性聚苯胺，制备聚苯胺（ＰＡｎ）复合粒子并用它们组成活性较高的电流变（ＥＲ）液．研究了ＰＡｎ复合粒子的结构与ＥＲ液性能的关系．结果表明在ＰＡｎ粒子表面涂覆聚乙烯醇或接枝聚丙烯酰胺等与ＰＡｎ能形成氢键或有化学键连接的绝缘物质可以既提高其ＥＲ液的电诱导屈服应力又降低漏电流密度．     

Preparation and characterization of PVC/PANI conductive composite with extremely low percolation threshold

Aniline was polymerized in the presence of poly(vinyl chloride) (PVC) powders in hydrochloric acid to in situ prepare poly(vinyl chloride)/polyaniline (PVC/PANI) composite particles. UV‐vis spectra and FT‐IR spectra indicate PANI in PVC/PANI composite particles possessed a higher oxidation state with decreased aniline content in reactants. Both conductivity and impact strength of the dodecylbenzenesulfonic acid (DBSA) doped PANI composites (PVC/PANI‐DBSA), which were compression molded from the in situ prepared PVC/PANI particles, increase with the pressing temperature and decrease with the increase of DBSA doped PANI (PANI‐DBSA) loading. An excellent electric conductivity of 5.06 × 10^?2 S/cm and impact strength of 0.518 KJ/m² could be achieved for the in situ synthesized and subsequently compression molded composite. Copyright © 2004 John Wiley & Sons, Ltd.     

Micelle-assisted one-pot synthesis of water-soluble polyaniline-gold composite particles

A micelle-based method to synthesize dispersed polyaniline (PANI)-Au composite particles by direct oxidation of aniline using AuCl4- as the oxidant is presented. The obtained composite particles have a core-shell structure, where Au nanoparticles of 20 nm mean diameter are encapsulated by PANI of well-defined tetrahedron shape with 150 nm average edge length. The polaron band of the dispersed PANI-Au composite particles is centered at 745 nm and is rather narrow compared to the broad 835 nm absorption of PANI synthesized by the IUPAC procedure. The surface plasmon absorption of Au nanoparticles normally centered at around 520 nm is absent in the composite particles with oxidized PANI. Our results point to a strong electronic interaction between the encapsulated Au nanoparticles and the shell of oxidized PANI. Films and pellets produced from these composite particles show a twofold higher conductivity than IUPAC PANI.     

Polymerization of anilinium–DBSA in the presence of clay particles: kinetics and formation of core‐shell structures

This paper is an extension of previous work on polymerization of anilinium–DBSA (dodecylbenzenesulfonic acid) in an aqueous dispersion in the presence of mica or talc silicate particles. The presence of mica or talc particles greatly accelerates the polymerization process of anilinium‐DBSA and an encapsulated structure is formed as well. The catalytic effect of various metallic cations which exist in the chemical compositions of mica or talc on the polymerization kinetics of anilinium‐DBSA was investigated. The conductivity results along with microscopy observations prove a well formed encapsulated structure for the polyaniline/mica composites, but less for the polyaniline/talc composites. The anilinium‐DBSA complex and mica aqueous dispersions pretreated at different temperatures prior to polymerization have shown a significant effect on the polymerization rate of anilinium‐DBSA. The higher the dispersion temperature, the higher is the polymerization rate found. Copyright © 2001 John Wiley & Sons, Ltd.     

Preparation and characterization of conducting polyaniline layered magnetic nano composite polymer particles

Considering the application potentials of organic materials possessing both conducting and ferromagnetic functions in various electronic devices, an attempt was made to prepare conducting polyaniline (PANI) layered magnetic nano composite polymer particles. Two routes were used to modify magnetic Fe₃O₄ core particles. In one route, seeded emulsion polymerization of methyl methacrylate (MMA) was carried out in presence of nano‐sized Fe₃O₄ core particles. In another route, cross‐linker ethyleneglycol dimethacrylate (EGDM) was used in addition to MMA. The modified composite particles were named as Fe₃O₄/PMMA and Fe₃O₄/P(MMA‐EGDM), respectively. Finally, seeded chemical oxidative polymerization of aniline was carried out in the presence of Fe₃O₄/PMMA and Fe₃O₄/P(MMA‐EGDM) composite seed particles to obtain Fe₃O₄/PMMA/PANI and Fe₃O₄/P(MMA‐EGDM)/PANI composite polymer particles. The modification of Fe₃O₄ core particles was confirmed by electron micrographs, FTIR, UV–visible spectra, X‐ray photoelectron spectra, X‐ray diffraction pattern and thermogravimetric analyses. A comparative study showed that crosslinking of intermediate shell improved the magnetic susceptibility and electrical conductivity of PANI layered magnetic nano composite particles. Copyright © 2013 John Wiley & Sons, Ltd.     

聚苯胺/钛酸钡纳米复合粒子的制备与表征

采用原位复合法制备出聚苯胺/钛酸钡复合粒子,借助TEM、XRD、FT-IR、 XPS、TG等分析手段研究了复合粒子的形貌、结构及其热性能.结果表明,复合粒子的粒径为1 μm左右,BaTiO3以40 nm左右的晶粒分散于聚苯胺基体之中,聚苯胺与钛酸钡之间存在化学键合作用,同时在一定程度上减少了纳米粒子的团聚.     

Growth of ramification-like ZnO rods in the presence of polyaniline

To obtain new materials with synergetic or complementary behaviors, polyaniline composite filled with ZnO rods in ramification-like structure was prepared by a hydrothermal approach. Comparative experiments of ZnO preparation in the presence of some metal ions were also carried out. The results indicated that the morphology of ZnO was strongly affected by the preparation condition. The method to grow ZnO rods in the presence of polyaniline offers a simple approach to obtain polyaniline composite filled with linear ZnO structure. The results of X-ray photoelectron spectroscopy show that the strong interaction between ZnO and polyaniline possibly exists to cause the charge transfer.     

石墨烯/聚苯胺复合材料的制备及其电化学性能

以苯胺和氧化石墨烯(GO)为原料, 采用电化学方法制备了石墨烯/聚苯胺(GP)复合材料. 利用X射线衍射(XRD)、扫描电镜(SEM)、拉曼(Raman)光谱、X射线光电子能谱分析(XPS)对其结构、微观形貌进行了表征,并对复合材料电化学性能进行了测试. 结果表明, 复合材料保持了石墨烯的基本形貌, 聚苯胺颗粒均匀地分散在石墨烯表面, 复合材料在500 mA·g^-1的电流密度下比电容达到352 F·g^-1, 1000 mA·g^-1下比电容为315 F·g^-1, 经过1000 次的充放电循环后容量保持率达到90%, 远大于石墨烯和聚苯胺单体的比电容. 复合材料放电效率高, 电解质离子易于在电极中扩散和迁移.     

核壳型聚苯胺/钛酸钡的结构及其电流变性能

用改进的溶胶-凝胶法制备了核壳型聚苯胺/钛酸钡复合微粉,通过TEM及FT-IR分析表征了其形貌及微观结构,用复合微粉与氯化石蜡油配制成无水电流变(ER)液,研究其不同膜厚核壳粒子的电流变性能.研究结果表明,聚苯胺/钛酸钡复合粒子配置成的电流变液的电流变性能较纯聚苯胺的为强;钛酸钡的涂层厚度对复合粒子电流变性能有重要影响;并在d=20 nm时获得最佳电流变性能.     

Synthesis and properties of silica/polystyrene/polyaniline conductive composite particles

In this study, silica/polystyrene/polyaniline (SiO₂/PS/PANI) conductive composite particles were synthesized by four sequential reactions. The nanosized SiO₂ particles were synthesized from tetraethoxysilane (TEOS) by a sol–gel process with water as the solvent medium, followed by a surface modification with triethoxyvinylsilane; then the surface modified SiO₂ particles were used as seeds to synthesize SiO₂/PS composite particles with soapless seeded emulsion polymerization. Finally, the SiO₂/PS particles were used as seeds to synthesize the SiO₂/PS/PANI conductive composite particles. The sol–gel process of SiO₂, the effect of surface modification, and several other factors that influenced polymerization of styrene in the soapless seeded emulsion polymerization will be discussed. Either potassium persulfate (KPS) or 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as the initiator to synthesize the uniform SiO₂/PS particles successfully, and the cross‐section morphology of the SiO₂/PS particles was found to be of a core–shell structure, with SiO₂ as the core, and PS as the shell. The SiO₂/PS particles were well dispersed in many organic solvents. In the following step to synthesize SiO₂/PS/PANI conductive composite particles, sodium dodecyl sulfate (SDS) played an important role, specifically, to absorb aniline onto the surfaces of the SiO₂/PS particles to carry out the polymerization of aniline over the entire surface of the particles. The conductivity of the SiO₂/PS/PANI composite particles approached that of semiconductive materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 342–354, 2005     

Synthesis,Characterization and Electrochemical Behavior of p-NiO/n-TiO2/Polyaniline Composites

The p-NiO/n-TiO2/polyaniline composites were synthesized via in situ polymerization of aniline. The structure and morphology of the composites were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR) and UV-Vis absorption spectroscopy. It was found that the p-n junction p-NiO/n-TiO2 particles were trapped in the polyaniline molecular matrix and the polyaniline was deposited on the surface of the particles to form a kind of flower cluster morphologies. The electrochemical behavior of the polyaniline composites was investigated. The electrochemical reactivity of the polyaniline was influenced by the p-NiO/n-TiO2 particles due to the effect of electron-hole pairs in these p-n junction particles. The reversibility of redox process and current intensity of the polyaniline composites with the changing of potential scan rate were also discussed.     

聚苯胺/聚砜复合材料的制备及其超级电容性能

通过化学聚合法,制备出盐酸掺杂聚苯胺（PANI）,将其与聚砜（PSF）溶液混合,定量滴加到玻碳电极上制得PANI/PSF复合膜电极。 采用扫描电子显微镜、红外光谱以及X射线衍射对其结构和形貌进行表征。 根据循环伏安曲线、恒电流充放电曲线和电化学阻抗,研究了其作为电极的超级电容性能。 结果表明,多孔结构的PANI/PSF复合材料具有良好的电容性能,其比电容可达到497 F/g,并且该超级电容器具有较小的内阻和较好的循环稳定性。     

Polyurethane/polyaniline and polyurethane‐poly(methyl methacrylate)/polyaniline conductive core‐shell particles: Preparation,morphology, and conductivity

Polyurethane/polyaniline (PU/PANI) and polyurethane‐poly(methyl methacrylate)/polyaniline (PU‐PMMA/PANI) conductive core‐shell particles were synthesized by a two‐stage polymerization process. The first stage was to produce a core of PU or PU‐PMMA via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as the surfactant. The second stage was to synthesize the shell of polyaniline over the surface of core particles. Hydrogen chloride (HCl) and dodecyl benzenesulfonic acid (DBSA) were used as the dopant agents. Ammonium persulfate (APS) was used as the oxidant for the polymerization of ANI. Different concentrations of HCl, DBSA, and SDS would cause different conformations of PANI chains and thus different morphologies of PANI particles. UV–visible spectra revealed that the polaron band was blue‐shifted because of the more coiled conformation of PANI chains by increasing the concentration of DBSA. Besides, with a high concentration of DBSA, both spherical‐ and rod‐shape PANI particles were observed by transmission electron microscope, and the coverage of PANI particles onto the core surfaces was improved. The key point of formation of rod‐type PANI particles was that DBSA was served with a high concentration accompanied with the existence of HCl or SDS. The better coverage of PANI particles over the core surfaces by charging higher DBSA concentrations resulted in a higher conductivity of hybrid particles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3902–3911, 2007