Thermal stability of electrochemically prepared polythiophene and polypyrrole

The degradation behaviour of electrochemically prepared polythiophene and polypyrrole has been studied by thermal gravimetric analysis technique. Studies on both the polymers show that they are more stable than polyacetylene but still undergo degradation reactions which involve two steps, viz. loss of dopant and then degradation of polymer backbone. The general features of degradation mechanisms are discussed.     

Aging effects on the interface state density obtained from current–voltage and capacitance–frequency characteristics of polypyrrole/p‐Si/Al structure

A metallic polypyrrole film has been directly formed on a p‐type Si substrate by means of an anodization method under conditions of constant current density by an electrolyte being held at a constant temperature of 55°C that was composed of 0.40M pyrrole and 0.10M tetrabutylammonium tetrafluoroborate. An aluminum electrode was used as an ohmic contact. The polypyrrole/p‐Si/Al structure has clearly demonstrated rectifying behavior by the current–voltage curves studied at room temperature. The capacitance–voltage–frequency curves of the structure have been measured at different frequencies at room temperature in dark. To observe the effect of the aging, the measurements were also repeated 7, 15, 30, 60, and 90 days after fabrication of the polypyrrole/p‐Si/Al Schottky diode. During the whole measurement process, the probe of holder on sample was fixed to eliminate effects of surface inhomogeneity. The interface state density distribution curves of device have been obtained from forward bias current–voltage (I‐V) and capacitance–frequency (C‐f) characteristics as a function of aging time. From these curves, the exponential growth of the interface‐state density from midgap toward the top of the valence band is very apparent. The shape of the interface state density distribution curves from the forward bias I‐V characteristics are very similar to those obtained from C‐f. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2313–2319, 2006     

导电聚合物及导电聚吡咯的研究进展

综述了导电聚合物的发展历史，导电聚合物的结构特征和基础性能、导电聚合物的类型及其合成方法；然后重点介绍了导电聚吡咯的研究进展。     

聚吡咯/蒙脱土纳米复合材料的表征与复合机理

以水为介质，用化学氧化就地吸附聚合法(in：situpolymerization)制备了聚吡咯(PPy)／蒙脱土(MMT)纳米复合导电材料。利用红外光措(FT-IR)、热失重(TGA)、X射线衍射(XRD)和四探针技术表征了材料的组成、结构和性能。结果表明PPy键已进入MMT内层空间，二者达到了纳米级复合。纳米复合材料的电导率已达50S／cm。     

PPy／SiO2纳米复合材料的合成与导电性能

以乙醚反应介质，用化学方法合成了聚吡咯纳米复合材料，利用红外光谱，四探针技术和透射镜表征了这些材料的组成，结构和导电性能，结果表明，载流子在ＰＰｙ分子链之间和ＰＰｙ聚集体之间有的传导性。     

导电聚合物型超电容器的比较研究

以掺杂聚(3 甲基噻吩)、掺杂聚吡咯或碳纳米管为活性物质,以偏氟乙烯 六氟丙烯共聚物为粘结剂,以乙炔黑为添加剂,将它们均匀混合后制成电极材料,再以LiClO4的1,4 丁内酯溶液为非水系电解质,以偏氟乙烯 六氟丙烯共聚物制成的微孔膜作隔膜,分别组装了Ⅰ型氧化还原超电容器、Ⅱ型氧化还原超电容器和新型的氧化还原 双电层混合型超电容器。并对上述超电容器进行了循环伏安与恒电流充放电测试。对它们的比较研究表明:Ⅱ型氧化还原超电容器具有较高的比能量(可达8.7Wh/kg),混合型超电容器则具有较高的比功率。这两种超电容器具有潜在的使用价值。     

聚吡咯在组织工程中的应用

近年来随着高分子材料在生物医学领域研究的深入，导电高分子以其特有的化学和物理性质，受到国内外学者的广泛重视。导电聚吡咯(PPy)在空气中稳定，导电性较高．能可逆氧化还原且无细胞毒性。PPy在生物医学领域的应用包括生物传感器、用于粘附蛋白质或DNA的基质及电化学控制释放药物的电极等。本文主要简述了PPy在组织工程中的应用。     

Use of inverse thin layer chromatography with amino acids to characterize molecular interactions on conducting polymers

A new method for characterizing conducting polymers, based on thin layer chromatography, is evaluated. Polypyrrole and polyaniline were used as the stationary phase and molecular probes were used to characterize favourable interactions on the polymers. Amino acids were chosen as the molecular probes because of the range of properties they exhibit and because there are numerous methods for their detection. Some difficulties were experienced in preparing stationary phases with suitable physical properties. However, once this was overcome, useful information was obtained with inverse TLC. Polypyrrole and polyaniline were both found to behave predominantly as anion-exchange materials.     

Chemical Synthesis and Morphology of β-Naphthalene Sulfonic Acid-Doped Polypyrrole Micro/Nanotubes

A preliminary result of the morphology and yield of chemically synthesized polypyrrole (PPY) using β-naphthalene sulfonic acid (NSA) and ammonium peroxodisulphate (APS) in aqueous medium is presented. Various micro/nanotubes were obtained using different dopant/monomer (D/M) ratios and temperature settings. Similar but shorter and sheet-like nanostructures were obtained without the use of surfactant NSA; with a fibre-like, loose and admixed physical outlook. The percentage yield (m/v) of the doped PPY was greater than that from the undoped, being 27-44 and 18-20, respectively with higher values obtained from the low temperature synthesis. The highest percentage yield of 44 was obtained from a D/M ratio of 0.8.     

Some properties of polypyrrole-paper composites

It is shown that porous materials such as paper can be impregnated with a conducting polymer by first soaking the paper in a solution of metal salt which acts as an initiator for subsequent polymerization. By using this procedure the conductivity of filter paper can be raised to as high as 2 (ohm cm)⁻¹ for an FeCl₃/H₂0/pyrrole combination. The role of the metal ion is discussea and it is pointed out that the impregnated papers exhibit both ionic and electronic conductivity. The polypyrrole paper composites exhibit some properties similar to carbon black-polymer composites.