Electrochemical preparation and characterisation of Poly(Luminol-Aniline) films

Electrochemical polymerisation of luminol (Lum) with aniline (Ani) is carried out potentiodynamically from acidic medium with different monomers concentration ratios. Aniline units incorporation in the polymer structure is observable in the current density/potential profiles of the polymerisation and characterisation, in acidic medium, by the development of two polyaniline (PAni) like redox switching processes with increasing aniline concentration. Poly(Luminol-Aniline) (P(Lum-Ani)) films characterised in acidic medium show electroactive and stable behaviour, in which the redox process ascribed as polyluminol (PLum) type is overlaid with that of PAni displaying pH sensitivity. Unlike PAni films, the P(Lum-Ani) polymer is electroactive and stable in basic medium and a single redox switching process is observed; its redox charge is enhanced with the increase of aniline concentration in the polymerisation solution.     

High-quality poly (N-phenyl-2-naphthylamine) films: Electrosynthesis and fluorescent properties

A novel conducting poly (N-phenyl-2-naphthylamine) (PPBNA) film was successfully electropolymerized by direct anodic oxidation of its monomer N-phenyl-2-naphthylamine in boron trifluoride diethyl etherate. The prepared PPBNA films showed good redox activity and structural stability even in concentrated sulfuric acid. The impedance spectra of PPBNA films demonstrated that the electron transfer resistance was around 80 Ω. The fluorescent results indicated that the emission band of PPBNA was red-shifted about 30 nm in comparison with that of the monomer. The fluorescent spectra exhibited that the monomer and PPBNA films were excellent blue-light-emitting and blue-green-light-emitting material, respectively.     

Schottky and heterojunction diodes based on poly(3-octylthiophene) and poly(3-methylthiophene) films of high tensile strength

Schottky and heterojunction diodes were fabricated using high tensile strength polymers. The heterojunction diode was fabricated by sequential electrochemical polymerisation of 3-methyl thiophene and 3-octyl thiophene on an indium-tin oxide (ITO) coated glass substrate. The high tensile strength enabled the bilayer (used in heterojunction diodes) or the poly 3-octyl thiophene films (used in the Schottky diodes) to be peeled of from the substrate and sandwich it between any two desired metals. It was found that the Schottky diodes of ITO (or Si)/POT/Al (or Zn) exhibit moderate rectifying behaviour and ITO (or Si)/POT/Cu devices exhibit ohmic contact. The POT/PMT heterojunction diode showed excellent rectification effect when sandwiched between any two metals irrespective of their work function. This shows that the results observed were solely due to the polymer/polymer interface. The Cu/POT/PMT/Cu heterojunction system was used in this study. The carrier-flow of the two semiconductors in the Cu/POT/PMT/Cu heterojunction diode was discussed in details. The rectification ratio, the barrier height, and the ideality factor for the heterojunction diode were found to be 64 (±1.2 V), 0.81 eV, and 5.7 under ambient conditions, respectively. Some of the important energy band parameters were also determined.     

C_(60)与高聚物复合膜的光电导性能(英文)

在 ITO导电玻璃上制备了聚乙烯基咔唑（ PVK） \C_(60)复合膜与分散红 I(PDRO)\C_(60)复合膜。 在 250W的红外灯照射下,发现 PDRO\C_(60)复合膜的光电导性能明显优于 PVK\C_(60)复合膜,并对 该现象作了初步解释。     

Enhancement of corrosion protection efficiency of iron by poly(aniline-co-amino-naphthol-sulphonic acid) nanowires coating in highly acidic medium

Nanowires of copolymers film based on aniline and 1-amino-2-naphthol-4-sulphonic acid were electrochemically synthesized on the iron electrode by cyclic voltammetry using oxalic acid as a supporting electrolyte. Protective properties of copolymer film on the iron surface in 1.0 M HCl solution was investigated by chronoamperometry, potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results showed that the copolymer film showed the significant shifting in the corrosion potential and greater charge transfer resistance. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface, reflecting the higher protection for corrosion of the iron in acidic medium. In addition, the film constitutes a physical as well as a chemical barrier layer due to the presence of -OH and -NH groups in ANSA unit, which provides passivity protection in polymer coatings. The mechanism of corrosion protection of iron by these copolymers was investigated by surface morphology and EIS techniques. In addition, by using scanning electron microscopy, the effect of morphology of copolymer on corrosion protection of metal was investigated.     

Photophysics and photochemistry of colloidal poly (p-phenylinevinylene) (PPV) polymer

The photophysical and photochemical behaviour of colloidal PPV polymers has been investigated by emission and photoelectrochemical studies. Emission studies indicated an increased conjugation length for PPV polymers on going from solution to the solid state. The quenching of the emission of PPV polymer by iodine can be used to probe the hole transfer by PPV–iodide complex with subsequent formation of I^*−. To elucidate the role of hole trapping in the process of photo-generation charge separation in various PPV/OTE electrodes, various electrolytes have been used. The values of photon-to-photocurrent conversion efficiency (IPCE) were evaluated from the short circuit photocurrent measurements at different excitation wavelengths. The close match between the IPCE and the absorption spectra shows that the photosensitization mechanism is operative in extending the photocurrent response of OTE/PPV into the visible. The maximum IPCE observed in the present experiments was 1.5% in the wavelength region of 425 nm which commensurates well with the reported values [M. Jonforsen, I. Ahmad, T. Johansson, J. Larsson, L.S. Roman, M. Svensson, O. Inganas, M.R. Andersson, Synth. Met. 119 (2001) 185]. From the photoelectrochemical response of an OTE/PPV electrode to visible light irradiation, the generation of photovoltage and photocurrent was prompt and was reproducible under several on–off cycles of illumination. Optimization of redox couple, electrolyte and film thickness is essential for improving the performance of PPV-based photoelectrochemical cells.     

Synthesis and characterization of conjugated poly (amino benzyl alcohol) and poly (ethylene glycol) for solid polymer electrolyte

A solid polymer electrolyte chemically bonded to a π-conjugated polymer was prepared for the use as a designed ladder-type structure by the graft copolymerization of poly (aminobenzyl alcohol) (PABA) with poly (ethylene glycol) (PEG). PABA was used as the frame for the ladder and the PEG as the rungs. The expected synergic effect afforded by the introduction of the ionic salts into the crosslinked conjugated polymer and PEG network was investigated as a function of its structure, morphology, and ionic conductivity. The insertion of the ionic salts into the PABA-PEG-PABA network led to the enhancement of the ionic conductivity compared to that of PEG/LiClO₄. The synergic effect may be explained by the more efficient segmental motion of the polymer chains or better ion mobility in the network due to the interrupted crystallization of the PEG chains. The fine tuning of the crosslinked conjugated polymer gel might enable it to show a faster response to electrochemical stimuli.     

Strategies for electrosynthesis of poly(vinylbenzyltrimethylammonium chloride) and composite films

Poly(vinylbenzyl trimethyl ammonium chloride) (PVT) exhibits functional properties, which have generated interest in the fabrication of PVT and composite films. New electrochemical strategies have been utilized for the deposition of PVT-zirconia composites. The problems, related to the electrodeposition of strong polyelectrolytes, such as PVT, were addressed by the development of charge compensation mechanisms. The deposition strategies involved electrophoretic cathodic deposition (EPD) of PVT and EPD or electrochemical synthesis of zirconia. The proof of concept investigations involved deposition yield studies under different conditions, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and electron microscopy studies. The electrochemical strategies can be used for electrodeposition of various composites, utilizing the properties of functional polymers and inorganic materials.     

Electrosysnthesis of poly(aniline-co-m-amino benzoic acid) for corrosion protection of steel

Conducting polymer (poly(aniline-co-m-amino benzoic acid)) has been deposited on steel surface by cyclic voltammetric technique. The copolymer film was characterized by FTIR, XPS and SEM techniques. The corrosion protection performance of copolymer film on steel was found out by impedance and tafel polarization methods in 1N HCl. The copolymer film was found to be highly corrosion resistant.     

Electrodeposition and characterization of nanocrystalline CoNiFe films

Nanocrystalline Co₄₅Ni₁₀Fe₂₄ films have been fabricated using cyclic voltammetry technique from the solutions containing sulfate, then characterized by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometer. Meanwhile, Electrochemical Impedance Spectroscopy technique has been employed to probe into the nucleation/growth behavior of Co₄₅Ni₁₀Fe₂₄ films. The results show that, the obtained Co₄₅Ni₁₀Fe₂₄ film possesses low coercivity of 973.3 A/m and high saturation magnetic flux density of 1.59 × 10⁵ A/m. Under the experimental conditions, the nucleation/growth process of Co₄₅Ni₁₀Fe₂₄ films is mainly under activation control. With the increase of the applied cathodic potential bias, the charge transfer resistance for CoNiFe deposition decreases exponentially.     

Electrochemical co-deposition of bimetallic Pt-Ru nanoclusters dispersed on poly(3,4-ethylenedioxythiophene) and electrocatalytic behavior for methanol oxidation

Nanoclusters of bimetallic Pt-Ru are electrochemically deposited on conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), which is also electrochemically deposited on a carbon paper substrate. The bimetallic deposition is carried out in an acidic electrolyte consisting of chloroplatinic acid and ruthenium chloride at 0.0 V versus saturated calomel electrode (SCE) on PEDOT coated carbon paper. A thin layer PEDOT on a carbon paper substrate facilitates the formation of uniform, well-dispersed, nano clusters of Pt-Ru of mean diameter of 123 nm, which consist of nanosize particles. In the absence of PEDOT, the size of the clusters is about 251 nm, which are unevenly distributed on carbon paper substrate. Cyclic voltammetry studies suggest that peak currents of methanol oxidation are several times greater on PtRu-PEDOT electrode than on Pt-Ru electrode in the absence of PEDOT.     

Structure and properties of SnS films prepared by electro-deposition in presence of EDTA

SnS thin films were deposited onto indium tin oxide (ITO) glass substrates by constant potential cathodic electro-deposition from aqueous solution containing stannous sulfate, ethylenediamine tetraacetate acid and sodium thiosulfate. The co-deposited potential was explored by cyclic voltammetry and the deposition potential (E) was roughly determined to be more negative than −0.70 V (vs. saturated calomel electrode, SCE). The analysis of the composition of the as-deposited films by X-ray fluorescence spectrometer indicated that stoichiometric SnS films could be obtained under the condition of E = −0.95 to −1.00 V. The films deposited at E = −1.00 V were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), and their transmission and reflectance spectra were measured. The as-deposited films were polycrystalline SnS compound with orthorhombic crystalline structure and the ratio of Sn and S was nearly 1. The films were uniform and compact with small grains. The direct band gap of the films was estimated to be about 1.10–1.43 eV with an absorption coefficient near the fundamental absorption edge larger than 4 × 10⁴ cm⁻¹.     

Electrochemical behavior and multilayer films of the sandwich-type polyoxotungstate complex {K10Co4(H2O)2(PW9O34)2}

The electrochemical behavior of the sandwich-type polyoxotungstate complex of K₁₀Co₄(H₂O)₂(PW₉O₃₄)₂ (Co₄(PW₉)₂) was investigated by cyclic voltammetry in aqueous solutions. The polyoxoanion exhibits two successive redox peaks originating from the tungsten-oxo framework. The electrochemical behavior for the Co^II species was not detected. Moreover, the multilayer films consisting of PEI and Co₄(PW₉)₂ were prepared by the layer-by-layer self-assembly method. The films were characterized by UV–vis spectroscopy, cyclic voltammetry and atomic force image. The films exhibit the electrochemical behavior of Co₄(PW₉)₂ polyoxoanion. Moreover, the films can catalyze the electrochemical reduction of NO₂⁻. Electron transfer to Fe(CN)₆^3−/4− redox probe was also investigated.     

基于OMMT/PVDF-HFP的锂离子电池用复合聚合物电解质

对蒙脱石进行改性,并用直接挥发溶剂法制备有机蒙脱石/聚偏氟乙烯-六氟丙烯复合聚合物电解质。用扫描电子显微镜和X射线衍射等对所制电解质性能进行表征,用交流阻抗和充放电实验研究聚合物电池的电化学性质。结果表明：直接挥发溶剂法制得的复合聚合物膜呈蜂窝状,孔穴丰富,强度增加,浸取电解液后室温离子电导率为1.51 mS/cm,电化学稳定窗口为5.5V;以LiCoO₂为正极制得的聚合物电池0.1C充放电,50次循环后容量保持率达到95.3%,倍率放电能力较好,有机蒙脱石的加入可改善电池的电极界面性质,提高电池充放电循环性能。     

On the mechanism of conductivity enhancement in plasma treated poly(3,4-ethylenedioxythiophene) films

The conductive poly(3,4-ethylenedioxythiophene): p-toluene sulfonate (PEDOT : PTS) films were prepared by gas-phase polymerization using CVD technique. PEDOT : PTS films with better electrical performance were produced by the additional doping with O₂ plasma after vapor phase polymerization. The mechanism for this conductivity enhancement is studied through surface structural analyses using Raman and X-ray photoelectron spectroscopy (XPS). The increase in conductivity is likely to be due to the generation of new functional groups such as carboxyl and hydroxyl groups that are acted as a dopant and the removal of the impurities on PEDOT: PTS surface with plasma treatment.     

两亲聚合物的合成及其在聚偏氟乙烯膜改性中的应用

利用异佛尔酮-二异氰酸酯(IPDI)、聚乙二醇(PEG)、甲基丙烯酸-β-羟乙酯(HEMA)和乙二醇(EG)合成了一种新型的聚氨酯丙烯酸酯大分子单体,并进一步与甲基丙烯酸甲酯(MMA)聚合,制备了一种既含有相对疏水链段、又含有相对亲水链段的两亲聚合物.最终产物添加到聚偏氟乙烯(PVDF)原材料中通过L-S相转化法制得聚合物分离膜.通过FT-IR表征了大分子单体的结构,GPC测定了两亲聚合物的分子量;通过纯水渗透通量、对牛血清蛋白(BSA)的截留率、接触角测定和耐污染性实验表征了超滤膜的性能.实验表明,两亲聚合物占聚合物质量分数的5%时,膜的纯水渗透通量由23.4 L/(m2.h)提高到78 L/(m2.h),而截留性能基本保持不变.在两亲聚合物质量分数从0~15%变化范围内,接触角由79°降至62°.膜通量衰减实验表明改性后膜的耐污染性得到提高.     

Electrochemical formation and characterisation of poly(3-methylthiophene)/WO3 nanocomposite films

Stable poly(3-methylthiophene)/WO₃ (PMeT/WO₃) nanocomposite films have been prepared by a two-step electrochemical method. At first the WO₃ film was grown by a potentiostatic method in tungsten electrolytes, and then PMeT was deposited on the WO₃ film by a potentiodynamic polymerisation method in 2?M solutions of 3-methylthiophene in 1-butyl-3-metyllimidazolium hexafluorophosphate ([BMIM]PF₆). The products are characterised in detail by multiform techniques: scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and Fourier-transform infrared spectroscopies (FTIR). The obtained PMeT/WO₃ film displays a significant enhancement of electrochemical activity and a higher stability than that of pure PMeT films.