聚2,6-吡啶二甲酸膜对儿茶酚和对苯二酚电氧化的催化性能及其应用

研究了２,６－吡啶二甲酸在玻璃电极上的电化学聚合物薄膜修饰电极的电化学特性,发现其对儿茶酚和对苯二酚析电化学氧化具有显著的催化作用,使它们的氧化电位降低,峰电流显著增大。从聚合物膜与多酚化合物的氢键作用对催化机理进行了探讨。该聚合物膜修饰电极可用于多酚的电化学测定。     

功能性聚合物薄膜修饰电极

化学修饰电极是当前在电化学、电分析化学方面十分活跃的研究领域。功能性聚合物薄膜由于其特殊的化学结构赋予其许多独特的功能,诸如选择性、分子识别、pH敏感、光化学敏感等;功能性聚合物修饰电极可以赋予电极许多特殊功能,拓展电极的应用范畴,故而备受关注。本文分别从分子印迹聚合物传感器和生物酶传感器制备的角度,综述在电极表面构筑功能性聚合物薄膜的材料以及方法,重点论述电泳沉积技术在电极修饰中的新应用。这些功能性聚合物薄膜在电极表面的构筑方法可以广泛的拓展到其它传感器的制备中,并指导特殊的传感器的制备,具有重要的研究和应用价值。     

可溶性聚酰亚胺电化学反应机理的研究

本文研究了三种可溶性聚酰亚胺（ＰＩ）在机溶剂和水溶液中的电化学行为，发现ＰＩ在有机溶剂中的电化学行为明显不同于水溶液，利用红外光谱技术才半经验发子轨道计算方法，结合电化学测试的结果，确证了ＰＩ的电化学反应的机理。     

等离子体聚合法修饰半导体光电极的研究——聚丙烯腈/n-GaAs,n-GaP电极

用导电聚合物修饰光电化学体系中的半导体电极,对于抑制电极的光腐蚀、改善电极特性及赋予其催化功能有明显的效果.在制备聚合物薄膜的几种方法中,等离子体聚合可得到高度交联、均匀、化学稳定性好的超薄膜,且成膜工序简单,已引起重视并取得初步应用。等离子体聚合法修饰导体电极国内外均有报道,但在修饰半导体电极方面的研究甚少。本文探讨了用这种方法在n-GaAs、n-GaP电极上制备聚丙烯腈(PAN)薄膜,并进行     

用修饰电极导数伏安法同时测定多巴胺和肾上腺素

研究了２,６－吡啶二甲酸在玻碳电极上电化学聚合的实验条件及修饰电极的电化学特性,发现该聚合物膜修饰电极对多巴胺和肾上腺素的电化学氧化有显著的催化作用,而对抗坏血酸等阴离子没有响应。利用在修饰电极上循环伏安阴极过程多巴胺和肾上腺素的峰电位不同,采用阴极化导数伏安法可同时测定多巴胺和肾上腺素。     

苯二酚在聚吡咯膜修饰电极上的催化反应

儿茶酚等有机化合物是人体内的电活性物质，直接参予人体内的各种生理过程．有关这类物质的电化学行为一直是生物化学和化学领域的重要研究课题之一．但这些物质在固体电极上的电极反应迟缓，过电位高，检测比较困难．利用化学修饰电极可以对这类物质的电极反应进行催化，可制成各种电流式传感器[1]，特别是聚合物膜修饰电极传感器有催化效率高、稳定性好等优点问，是目前电化学传感器研究中的一个主要方面．聚毗咯膜（PPy）修饰电极自从出现以来已得到了广泛的应用，在电分析化学领域更具有稳定性好，制备条件简便等优点．一些在固体电极…     

聚酰亚胺LB膜研究进展

聚酰亚胺（ＰＩ）是一种高性能聚合物材料，通过Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔｔ膜（ＬＢ膜）技术实现ＰＩ分子排列的有序化，可以使ＰＩ的某些性能更充分体出现来，详细总结了ＰＩＬＢ膜的制备方法，对其在气体分离，光敏性，液晶取向，介电以及光电导等方面性质的研究现状进行了较为全面的综合，对ＰＩＬＢ的研究和应用前景作了简要展望。     

N—（3—二茂铁乙酰胺基）丙基吡咯聚合物修饰的葡萄糖电极的研究

于铂电极上修饰一层Ｎ－（３－二茂铁乙酰胺基）丙基吡咯聚合物膜，应用循环伏安法对聚合物的电化学性能进行研究，发现了Ｎ－位取代吡咯聚合物的电活性大大降低，聚合物中 二茂铁基团氧化还原性能稳定，制成酶电极后，在＋０．２Ｖ以葡萄糖有一明显的催化峰，而对抗坏血酸，尿酸则几乎没有呼应，该葡萄糖电极性能稳定，连续工作十天，响应值基本不变。     

肾上腺素在二苯并18冠6修饰玻碳电极上的伏安特性

化学修饰电极自20世纪70年代中期问世以来，很快成为电化学和电分析化学十分活跃的研究领域。1967年Pedersen等报道了冠醚化合物后，冠醚化学及其应用引起了广大化学工作者的重视。冠醚在毛细管电泳和高效液相色谱中的应用已有不少报道，但冠醚在修饰电极方面研究报道并不多，冠醚修饰电极有的是采用组合法将冠醚与电极材料混合制成糊状电极；有的是用电沉积法将冠醚修饰在玻碳电极或铂电极上。     

甲醇在铂微粒修饰的聚硫堇电极上的电催化氧化

利用电化学循环伏安和现场ＦＴＩＲ反射光谱等技术研究了甲醇在铂微粒修饰的聚硫堇电极上的电催化氧化。结果表明，循环伏安法制备的铂微粒均匀分散于聚合物膜上，其粒径大小约为３０－１３０ｎｍ；复合修饰电极对甲醇电化学氧化呈现了较高的催化活性，其催化活性的大小依赖于Ｐｔ载量。现场ＦＴＩＲ光谱实验揭示了线性吸附的ＣＯ物种是甲醇在复合电极上氧化的唯一中间体，这种吸附的ＣＯ物种在复合修饰电极上更容易被氧化为最终产物     

溶剂对聚酰亚胺电化学行为的影响

运用电化学循环伏安等方法研究了有机溶剂对可溶性聚酰亚胺(PI)电化学行为的影响.结果表明,PI在一些溶剂中能进行电化学反应.红外光谱研究表明溶剂对PI电化学行为的影响主要取决于不同结构的溶剂与PI之间的相互作用.     

Synthesis of a hexafluoropropylidene-bis(phthalic anhydride)-based polyimide and its conducting polymer composites with polypyrrole

A new electrically conducting composite film from polypyrrole and 4,4′-(hexafluoroisopropylidene)-bis(phthalic anhydride)-based polyimide was prepared. Pyrrole and the dopant ion can easily penetrate through the polyimide substrate and electropolymerize on the platinum (Pt) electrode due to the swelling of the polyimide on the metal electrode. The electrochemical properties of polypyrrole-polyimide (PPy/PI) composite films have been investigated by using cyclic voltammetry. The PPy/PI composite film is suitable for use as the electroactive material owing to its stable and controllable electrochemical properties. The electrical conductivity of composites falls in the range 0.0035–15 S/cm. Scanning electron micrograph, FTIR, and thermal studies indicate that PPy and PI form a homogeneous material rather than a simple mixture. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3009–3016, 1997     

Electrochemical assay of the relationship between the inhibition of phosphatidylinositol 3-kinase pathway and estrogen receptor expression in breast cancer

Breast cancer has become one of the most threatening diseases to women throughout the world. Emerging evidence implies that estrogen receptor (ER) and phosphatidylinositol 3-kinase (PI3K) pathways play central roles in both breast cancer progression and response to therapy. In this work, we have probed into ER expression related to the PI3K pathway at the protein level with an electrochemical technique based on the detection of ER proteins in nuclear extracts with an Exonuclease III protection-based strategy. Experimental results show that an increased number of ER proteins can be detected upon PI3K inhibition, demonstrating the reversal effect of the PI3K inhibitor on ER expression. Moreover, treatment with different concentrations of the PI3K inhibitor NVP-BEZ235 can result in a dose-dependent alteration of ER protein levels, implying an intimate link between ER and PI3K pathways. This work may be a great help to understand the mysteries underlying PI3K-related endocrine resistance and to evaluate the effect of therapeutic interventions in the future.     

Facile fabrication and characterization of polyimide nanofiber reinforced photocured hybrid electrolyte for Li‐ion batteries

In this study, a novel ion conductive polyimide (PI) nanofiber reinforced photocured hybrid electrolyte has been fabricated. Polyimide fibers were fabricated with the reaction between 4,4′‐oxydianiline (ODA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) followed by electrospinning and thermal imidization methods. Then, PI electrospun fibers were dipped into hybrid resin formulation containing bisphenol A ethoxylate dimethacrylate (BEMA), poly (ethylene glycol) methyl ether methacrylate (PEGMA) and 3‐(methacryloyloxy) propyltrimethoxysilane (MEMO) and then photocured to prepare PI nanofiber reinforced electrolyte membrane. Photocured membranes were soaked into lithium hexafluorophosphate (LiPF₆) before measuring electrochemical stability and ionic conductivity of hybrid polyelectrolyte. The chemical structure and electrochemical performance of the electrolytes were examined by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and scanning electron microscopy (SEM) analysis. The incorporation of MEMO into organic matrix effectively increased the modulus from 2.83 to 5.91 MPa. The obtained results showed that a suitable electrolyte for Li‐ion batteries with high lithium uptake ratio, high conductivity (7.2 × 10^?3 S cm^?1) at ambient temperature and wide stability window above 5.5 V had been prepared. Copyright © 2017 John Wiley & Sons, Ltd.     

Construction of Safety and Non-flammable Polyimide Separator Containing Carboxyl Groups for Advanced Fast Charing Lithium-ion Batteries

With the wide applications of lithium-ion batteries (LIBs) in electronic devices and electric vehicles, it is of great importance to improve their safety and electrochemical performance. Herein, soluble polyimides (PI) containing carboxyl groups (?COOH) were synthesized by a simple one-step method and PI separators with sponge-like, interpenetrating porous structures were prepared via non-solvent induced phase separation (NIPS). The obtained PI separators exhibited excellent thermal stability and fire-resistance properties, with the electrolyte uptake of 344% and good dimensional integrity in air at 200 °C. The results showed that the lithium-ion transference number of the obtained PI separator could reach 0.48, which was much higher than that of the Celgard-2400 separator (0.38). The Li/LiFePO₄ half-cell with the PI separator showed excellent cycle capability and high-rate performance with a high capacity of 121.80 mA·h·g^?1 at 5 C, which was better than that of the cell with the Celgard-2400 separator (54.3 mA·h·g^?1), demonstrating the promising applications of this PI separators in LIBs.

     

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.     

Transport of water dissolved oxygen in polymers via electrochemical technique

Transport properties of polymer membranes for dissolved oxygen in a liquid-membrane-liquid configuration were investigated by using an electrochemical technique based on the use of the Clark oxygen electrode. The oxygen permeability and the diffusivity coefficient in a polymer-water system can be determined accurately by appropriate choice of the experimental conditions. Polymers that do not absorb water such as polyethyleneterephtalate (PET) and bioriented polypropylene (OPP) were tested for permeation experiments in both gas-membrane-gas and liquid-membrane-liquid configuration. Data obtained in the liquid-membrane-liquid configuration with the electrochemical technique show excellent agreement with those obtained with the gas-membrane-gas configuration. The permeability of water saturated Kapton® polyimide (PI) for dissolved oxygen was also evaluated and compared with data obtained in the gas-membrane-gas configuration.     

Electrochemical deposition of nanosemiconductor CuSe on multiwalled carbon nanotubes/polyimide membrane and photoelectric property researches

Nanosemiconductor CuSe were prepared on self-made multiwalled carbon nanotubes/polyimide (COOH-MWCNTs/PI) membrane electrode by electrochemical atomic layer deposition (EC-ALD). By exploring the elements, electrochemical properties through cyclic voltammetry and differential pulse-stripping voltammetry, -0.2 and -0.55 V are finally identified as the deposition potential of copper and selenium, respectively. Current density ? time curve obtained via amperometric I–t processes indicates the formation of copper layer by a two-dimensional nucleation and growth mechanism, while selenium growth is considered to be diffusion control process. X-ray powder diffraction data reveals the preferred orientation of the CuSe crystal is at (112) plane. Field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis show that the obtained CuSe thin film are short virgate nanostructure, and the average atomic percentage of Cu:Se is close to one. Furthermore, the ultraviolet visible (UV–Vis) transmission measurements provide a band gap of 2.0 eV. Open-circuit potential (OCP) and amperometric I–t experiments illustrate the CuSe thin film to be p-type semiconductor. Obtained results indicate that the CuSe thin film depositing on COOH-CNTs/PI membrane is appropriate to serve as the solar energy transfer material.     

Synthesis and Characterization of Aramid Fiber‐Reinforced Polyimide/Carbon Black Composites and Their Use in a Supercapacitor

The aramid fabric (AF )‐reinforced polyimide (PI ) composites filled with carbon black (CB ) were fabricated by means of a thermal imidization and their mechanical, thermal and electrochemical behaviors were comparatively investigated. Experimental results showed that the tensile strength of composite increased with an increase of the CB , meanwhile, the addition of 5 wt% CB and AF increased the tensile modulus to 5682.0 MPa . The superior mechanical properties of the composites were attributed to the good dispersion and effective stress transfer between the polymer and CB , as evidenced by the results from X‐ray diffraction (XRD ) and morphological studies. Besides, the thermal‐nonoxidative stability of PI was significantly improved by the incorporation of CB and AF . Furthermore, the CB /AF /PI composite was employed as the supercapacitor electrode in the 6 mol/L KOH aqueous electrolyte solution, which exhibited a specific capacitance of 510 F•g⁻¹ at 10 mV •s⁻¹. It also exhibited excellent long‐term stability, and the energy density was stable with the increase in the power density. The super performance of the composite electrode is attributed to the synergistic effects of CB particles and organic polymer.     

New polymer electrolyte membrane for medium-temperature fuel cell applications based on cross-linked polyimide Matrimid and hydrophobic protic ionic liquid

New hydrophobic protic ionic liquid, 2-butylaminoimidazolinium bis(trifluoromethylsulfonyl)imide (BAIM-TFSI), has been synthesized. The ionic liquid showed good thermal stability to at least 350 °C. The conductivity of BAIM-TFSI determined by electrochemical impedance method was found to be 5.6 × 10^?2 S/cm at 140 °C. Homogeneous composite films based on commercial polyimide (PI) Matrimid and BAIM-TFSI containing 30–60 wt% of ionic liquid were prepared by casting from methylene chloride solutions. Thermogravimetric analysis data indicated an excellent thermal stability of PI/BAIM-TFSI composites and thermal degradation points in the temperature range 377 °C–397 °C. The addition of ionic liquid up to 50 wt% in PI films does not lead to any significant deterioration of the tensile strength of the polymer. The dynamic mechanical analysis results indicated both an increase of storage modulus E′ of PI/BAIM-TFSI composites at room temperature and a significant E′ decrease with temperature compared with the neat polymer. The cross-linking of the PI with polyetheramine Jeffamine D-400 allowed to prepare PI/Jeffamine/BAIM-TFSI (50%) membrane with E′ value of 300 MPa at 130 °C. The ionic conductivity of this cross-linked composite membrane reached the level of 10^?2 S/cm at 130 °C, suggesting, therefore, its potential use in medium-temperature fuel cells operating in water-free conditions.