Influence of the magnitude and direction of electric field on the transport and growth property of deposited polyaniline films

Polyaniline (PANI) films were deposited by electrochemical polymerization of aniline monomer on a fluorine-doped glass substrate at room temperature under different electric field directions. The as-synthesized PANI films obtained at different growth cycles were characterized by AC impedance spectroscopy and scanning electron microscopy (SEM). The results revealed that the film morphology, transport kinetics, and electrical properties are strongly dependent on the electric field direction and magnitude of the applied field during electropolymerization. The SEM morphology and AC impedance (modulus spectroscopy) indicate that a more homogeneous, high-porous, and conducting PANI film is induced by horizontal electric field direction (HEFD) electrodeposition, whereas the modulus spectroscopy of the PANI film deposited by vertical electric field direction (VEFD) reveals that VEFD deposition favours two-dimensional growth of PANI. The obtained polymer is more of dielectric in nature due to preferable dendritic growth which is supported by SEM analysis.     

Tubular linear actuators using conducting polymer, polypyrrole

Conducting polymers show an electrochemomechanical deformation (ECMD), which is able to be utilized as soft actuators. A tubular linear actuator of polypyrrole film is fabricated and the characteristics are examined. The film was electrochemically prepared on an acryl resin rod in an aqueous electrolyte solution of pyrrole and dodecylbenzensulfonic acid (DBS), followed by removing the rod. The actuations of tubular polypyrrole film due to ECMD in various conditions have been examined to clarify the mechanism. It has been found that the tubular actuator elongates upon reduction with the strain of 7%, which is more than twice of that observed in a rectangular film. The facts indicate that cations play the role of dopants instead of large DBS anion and the tubular structure gives the better performance for large strain.     

还原氧化石墨烯表面聚苯胺纳米阵列的制备及电化学电容性能

本文以阳极氧化铝(AAO)膜为模板,通过恒电位法在自组装还原氧化石墨烯(rGO)膜表面制备有序聚苯胺(PANI)纳米线阵列。通过拉曼光谱和场发射扫描电子显微镜分别对其结构和微观形貌进行了表征,并对PANI纳米线阵列的电化学电容性能进行了测试。结果表明,rGO膜表面可电沉积PANI,电沉积得到的PANI纳米线阵列具有比PANI薄膜材料更高的电容和比电容。     

聚苯胺/二氧化钛复合薄膜的制备及其气敏性能

室温条件下, 运用静电力自组装和原位化学氧化聚合相结合的方法制备了聚苯胺/纳米二氧化钛(PANI/TiO2)复合薄膜和聚苯胺(PANI)薄膜, 并通过XPS和SEM对薄膜进行了分析表征. 采用平面叉指电极式器件制备了PANI/TiO2复合薄膜和PANI薄膜气体传感器, 研究了其在常温下对有毒气体NH3和CO 的敏感性能. 结果表明, PANI/TiO2复合薄膜较PANI薄膜具有更优的灵敏度和响应恢复特性.     

TiO_2聚苯胺复合膜的光电化学

利用电化学方法制备了TiO2 聚苯胺 (PANI)复合膜 .该膜具有比TiO2 或PANI膜更宽的吸收谱区 ,并且不同于利用聚苯胺光敏化的TiO2 膜 ,表现为两者复合材料膜的性质 .扫描电镜图表明 ,TiO2 微粒不完全覆盖着PANI膜 .根据TiO2 微粒光电流谱带的阈值能可得复盖在部分氧化态聚苯胺膜上的TiO2 微粒的禁带宽度为 3.0eV .部分氧化态聚苯胺膜的光电流谱遵循Fowler定律 ( 1/2 ～hυ成线性 ) .通过Fowler图得出部分氧化态聚苯胺的绝缘母体禁带宽度为 3.33eV ,并证实该绝缘母体为还原态聚苯胺 .从Mott Schottky图得到在 0 .0 5mol/LK3Fe(CN) 6 /K4 Fe(CN) 6 溶液中 (pH =8.52 )部分氧化态聚苯胺的平带电位为 0 .13V ,掺杂浓度为 5.3× 10 18cm- 3;TiO2 PANI复合膜的平带电位为 - 0 .6 5V ,掺杂浓度为 9.1× 10 19cm- 3.解释了TiO2 PANI复合膜的光电化学过程并描绘出其能带图 .利用TiO2 PANI复合膜能够有效地光降解苯酚溶液 .     

Electrocatalytic oxidation of formic acid on platinum particles dispersed in SWNT/PANI composite film

Single-walled carbon nanotube (SWNT)/Polyaniline (PANI) composite film with good dispersion was prepared by electropolymerization of aniline containing well-dissolved SWNTs. Platinum (Pt) particles were electrodeposited on the SWNT/PANI composite film subsequently. The presence of SWNTs and platinum in the composite film was confirmed by XRD analysis. Four-point probe investigation exhibits that the electrical conductivity of SWNT/PANI composite film is significantly higher than that of pure PANI film. Cyclic voltammogram and Chronoamperogram show that Pt-modified SWNT/PANI electrode performs higher electrocatalytic activity than Pt-modified pure PANI electrode toward formic acid oxidation.     

制备条件对PANI/PATP/Au和TiO_2-PANI/PATP/Au膜光电化学性能的影响

应用电化学方法在不同条件下制备聚苯胺 (PANI)膜和TiO2 -PANI复合膜 ,并对其光电化学性能进行研究 .实验表明 ,制备条件是影响膜光电化学性能的重要因素 .对氨基硫酚 (PATP)的组装有利于改善PANI膜的附着力 ;部分氧化态PANI膜的光电化学响应明显优于还原态和氧化态PANI膜的光电化学响应 ;部分氧化态PANI膜的厚度对其光电化学性能有一最佳值 ;热处理虽然有利于改善TiO2 的光电化学性能 ,但温度太高 ,将破坏PANI膜的表面结构 ,对于TiO2 -PANI复合膜有一最佳的热处理温度 .优化制备条件大可改善TiO2 -PANI复合膜和PANI膜的光电化学性能     

An Electrochemical Study on the Corrosion Inhibition of Stainless Steel by Polyaniline Film

Polyaniline(PANI)film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte.The potential sweep rates were changed to achieve the PANI film with different thickness and structures.Protective properties of the PANI film for corrosion of stainless steel in 3% NaC1 aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance,reflecting higher inhibition for corrosion of the stainless steel.     

Nickel foam-supported porous NiO/polyaniline film as anode for lithium ion batteries

Nickel foam-supported porous NiO film was prepared by a chemical bath deposition technique, and the NiO/polyaniline (PANI) film was obtained by depositing the PANI layer on the surface of the NiO film. The NiO film was constructed by NiO nanoflakes, and after the deposition of PANI, these nanoflakes were coated by PANI. As an anode for lithium ion batteries, the NiO/PANI film exhibits weaker polarization as compared to the NiO film. The specific capacity after 50 cycles for NiO/PANI film is 520 mAh g⁻¹ at 1 C, higher than that of NiO film (440 mAh g⁻¹). The improvement of these properties is attributed to the enhanced electrical conduction and film stability of the electrode with PANI.     

铂粒子修饰单壁碳纳米管/聚苯胺复合膜对甲醛的电催化氧化

在溶有单壁碳纳米管(SWNTs)的苯胺溶液中, 通过电化学共聚合法成功制备了单壁碳纳米管(SWNT)/聚苯胺(PANI)复合膜. 用电沉积法将铂沉积到SWNT/PANI复合膜上. 样品的成分和形貌分别用XRD和SEM表征. 四探针和电化学交流阻抗的研究表明被PANI包裹的SWNTs整齐地排列在复合膜中, 从而提高了复合膜的电导率, 促进了电荷转移. 循环伏安(CV)说明Pt修饰的SWNT/PANI复合膜对于甲醛氧化具有良好的电催化活性及稳定性. 研究结果表明SWNT/PANI复合膜是一种非常好的催化剂载体, 有着广泛的应用前景.     

Enhanced Thermoelectric Properties of Polyaniline Nanofilms Induced by Self‐Assembled Supramolecules

Polyaniline (PANI) is one of the most promising candidates for flexible organic thermoelectric (TE) applications owing to its relatively low cost and high stability. Herein, the self‐assembled supramolecule (SAS) (3,6‐dioctyldecyloxy‐1,4‐benzenedicarboxylic acid) was used as an additive and was introduced into PANI films as a template. Raman spectroscopy, X‐ray diffraction, and conductive atomic force microscopy analyses demonstrated that the highly ordered chain structure of PANI was achieved by chemical interactions between PANI and the SAS. Moreover, the ordered regions in the PANI‐SAS film increased with a decrease in the film thickness. Consequently, the TE properties of PANI‐SAS films were not only much higher than those of PANI films, but they also increased with a decrease in film thickness. The maximum TE power factor of the PANI‐SAS film reached 31 μW m^?1 K^?2, which is approximately six times higher than the power factor of a PANI film with a similar thickness. This work offers a promising way to prepare PANI thin films with enhanced TE properties.     

Biomimetic fabrication of lotus-leaf-like structured polyaniline film with stable superhydrophobic and conductive properties

Superhydrophobic surfaces were successfully prepared on Ti/Si substrates via the fabrication of conductive polyaniline (PANI) nanowire film. The PANI nanowire film was synthesized by electrodeposition of aniline into the pores of an anodic aluminum oxide (AAO) template on Ti/Si substrate followed by the removal of the template. The surface showed conductivity and superhydrophobicity, even in many corrosive solutions, such as acidic or basic solutions over a wide pH range. Field emission scanning electron microscopy (FE-SEM) demonstrated that the binary geometric structures at micro- and nanometer scale bestowed the prerequisite roughness on the surfaces. The chemical surface modification made the PANI nanowire film superhydrophobic. The results demonstrated that the PANI nanowire film will have good potential applications in the preparation of conductive superhydrophobic surfaces.     

Phenol assisted deaggregation of polyaniline chains: simple route to high quality polyaniline film

High conducting polyaniline films were readily prepared by in situ chemical oxidative polymerization/deposition of aniline in the presence of a very small amount of organic additive such as phenol. The conductivity of a thin ( approximately 150 nm) polyaniline film synthesized in the presence of 0.01 wt % of phenol ( r-PANI) is an order of magnitude higher (as well as better conducting homogeneity) than that of a film (PANI) obtained from the conventional method without an additive. r-PANI also has better adhesion and electrochemical stability/reversibility, more transparency in the visible-light region, and faster/easier doping/dedoping response compared to PANI. The function of phenol molecule is to avoid the formation of the inter- and/or intrachain hydrogen bonding during the growth of the polyaniline chains. The deaggregation/reducing intrachain hydrogen bonding of polyaniline chains by phenol molecules was revealed with IR, SAXS, and SEM data. All these data supported that phenol does assist the deaggregation of polyaniline chains during the growth of polymer chains or nanorods.     

Optimization of the thickness of a conducting polymer, polyaniline, deposited on the surface of poly(vinyl chloride) membranes: a new way to improve their potentiometric response

Repeated depositions of polyaniline (PANI) have been used to control the thickness of the polymeric film deposited on poly(vinyl chloride) (PVC) membrane surface. The oxidation of aniline was carried out in a dispersion mode, i.e. in the presence of poly(N-vinylpyrrolidone) (PVP). Two kinds of PVC were used for this purpose: a non-plasticized PVC for the study of PANI deposition and PVC, plasticized with nitrophenyl octyl ether (NPOE), as a prototype of a liquid membrane electrode. The results of UV-visible and FTIR spectroscopies and electron microscopy showed that (1) the film thickness increased by about equal increments of ∼40 nm after each polymerization, and (2) the interface with PVC was constituted by PANI film and adhering PANI-PVP colloidal particles.The various thicknesses of the deposited PANI films affected the potentiometric response of the NPOE/PVC membrane with and without an anion-exchanger. The potentiometric anionic response was observed with a minimal thickness of PANI film on the blank NPOE/PVC membrane. Sensitivity of the PANI film to pH occurred only with a blank NPOE/PVC membrane coated with a thick polymeric film, while it was strongly suppressed by the presence of a lipophilic anion-exchanger, tridodecylmethylammonium chloride (TDDMACl), in the membrane, regardless of the thickness of the polymer film. The thickness of the PANI film did not affect the anionic selectivity pattern of TDDMACl-based membranes to any great extent, but its presence improved and stabilized their potentiometric characteristics (sensitivity, linear-response range).     

乳液聚合中聚苯胺膜形成的动力学研究

以(NH4)2S2O8(APS)为氧化剂,十二烷基苯磺酸(DBSA)同时为乳化剂和掺杂剂,采用乳液聚合方法制备聚苯胺膜(PANIfilm),用石英晶体微天平(QCM)实时监测聚苯胺膜的形成过程,并对其动力学过程进行研究.结果表明,聚苯胺成膜反应对APS是0.5级,对苯胺是1级,聚苯胺膜增长速率随温度的升高而增加,而聚苯胺膜的最终沉积量却减小,表观活化能Ea=41.15kJ/mol,与均相溶液聚合成膜法的结果相近;随着DBSA浓度的增加,聚苯胺膜增长速率减小,而最终的沉积量增大.     

纳米纤维聚苯胺在电化学电容器中的应用

采用脉冲电流方法（PGM）合成了具有纳米纤维结构的导电聚苯胺（PANI）.扫描电子显微镜对膜层观察表明, PANI膜是由直径约为100 nm的掺杂态聚苯胺纤维交织而成.以纳米纤维状聚苯胺组成电化学电容器,研究了其电化学电容性能,并与恒电流方法（GM） 制备的颗粒状PANI电容器性能进行了比较.结果表明,在相同的沉积电量下,PGM制备的纳米纤维状PANI电化学电容器比颗粒状PANI电化学电容器具有更大的电容容量,其电化学电容器的比电容可高达699 F•g－1,能量密度为54.6 Wh•kg－1.并且该电化学电容器具有良好的充放电性能和循环寿命.     

聚苯胺在聚酰亚胺膜基体表面的原位沉积成膜机理

采用分散聚合方法,在聚酰亚胺(PI)膜基体表面原位成膜,制备聚苯胺-聚酰亚胺-聚苯胺(PANI-PI-PANI)导电复合膜.通过反应历程跟踪、扫描电镜(SEM)及静滴接触角-界面张力测量仪研究了PANI在PI基体表面原位成膜的过程及其驱动力.结果表明,PANI在PI基体表面的成膜过程有3个阶段:含苯胺的结构单元(包括An盐酸盐、An阳离子自由基及低聚物)在PI表面吸附成核阶段、膜快速增长阶段和增长完成阶段;PANI膜由PANI小颗粒逐渐堆积而成,直至覆盖整个PI膜表面;PANI成膜的主要驱动力来自亲水-疏水相互作用.     

Preparation and characterization of a conductive polyaniline/polysulfone film and evaluation of the effect of co-solvent

A novel conductive dense membrane composed of polyaniline (PANI) and polysulfone (PSU) was prepared. To improve the solubility of PANI in N-methyl pyrrolidone (NMP) and consequently increase the conductivity of the eventual film, a tertiary amine (1,3-dimethyl-2-imidazolidinone, DMI) was added to the solvent as a co-solvent. Different PANI solution concentrations in NMP/DMI were used to make blend films via solution blending with PSU solution in NMP in different ratio’s of PANI/PSU. The effect of the PSU fraction on the properties of the membrane has been investigated. The electrical conductivity, doping degree, crystallinity, miscibility of the polymers and shape stability were investigated. It was observed that an increase in the PSU fraction causes a decrease in the conductivity as well as less film deformation after doping. The conductivity and shape stability of the blend film were optimized by a change in PANI concentration in the casting solution and a change in the PSU fraction. The best conductivity was achieved using 3% PANI solution in NMP/DMI and the minimum percentage of PSU, allowing good shape stability after doping, was found to be 40%.     

Characterization of stainless steel electrode modified by a thin film of polyaniline containing pt particles and its electrocatalytic activity for methanol oxidation

The catalytic behavior of stainless steel (SS) electrode modified by a thin film of polyaniline (PANI) containing platinum particles was studied for electrooxidation of methanol and compared with a platinated Pt/PANI electrode in acidic aqueous solution. Cyclic voltammetry (CV), chronoamperometry, CO stripping techniques were used to investigate electrochemical properties and electrocatalytic activity of SS/PANI/Pt and Pt/PANI/Pt electrodes. The morphology and particle size of Pt catalysts were characterized by Transmission Electron Microscopy (TEM) measurement. The effects of various parameters such as thickness of polymer film, medium temperature and stability of the modified electrodes on methanol oxidation were also investigated. The results indicated that the modified SS electrode exhibited a considerably high electrocatalytic activity on the methanol oxidation as well as the modified Pt electrode.     

Polyaniline film deposition from the oxidative polymerization of aniline using K2Cr2O7

The deposition of the polyaniline (PANI) films was monitored using the quartz crystal microbalance (QCM) technique. The films were grown from an aqueous dilute hydrochloric acid solution by the chemical oxidation of aniline using potassium dichromate (KDC). The effect of the initial molar ratio of the KDC/aniline on the yield and the growth rate of the PANI films were studied. There is no optimum initial molar ratio of KDC/aniline of PANI film deposition. Also there was a small depletion period and no degradation to the deposited PANI films. The order of the polymerization kinetics was studied with respect to KDC. The UV-visible spectra of the PANI films grown onto a glass support immersed into the bulk solution were measured. The absorption of the PANI film with the time of polymerization was compared to the growth of the PANI film thickness with time determined from the QCM technique. The characteristics of the PANI film deposition were compared to the corresponding ones that were observed during the oxidative polymerization of aniline with ammonium persulphate (APS).