ON THE IODINE-DOPING OF POLYANILINE AND POLY-ORTHO-METHYLANILINE

The reactions of polyaniline and poly-omicron-methylaniline of different oxidation degrees with I2 were followed by FTIR and electrical conductivity measurements. The results showed that the reaction of common polyanilines with I2 was oxidation in nature whereas that of the fully reduced ones was doping. The latter took place in two steps: oxidation of benzene-diamine units into quinone-diimine units (redox between I2 and the polymer chain) and formation of a conjugated system consisting of four aromatic rings (intramolecular chain redox).

MOLECULAR CHAIN STRUCTURE OF DOPED POLYANILINE

The chain structure of polyaniline doped with HCl or CF_3COOH has been investigated by FTIR, solid state ~(13)CNMR, resonance laser Raman and UV-VIS spectroscopies. The results show that during the protonic acid doping, a partial redox reaction takes place between the quinone-diimine and benzene-diamine units and it leads to a long conjugate system with a certain charge distribution.

STUDY ON POLYANILINE FILM WITH HIGH-DENSITY AND HIGH MECHANICAL STRENGTH

Free-standing film of polyaniline with excellent mechanical and electrical properties has been successfully prepared by using the solution-casting method. The results show that its tensile strength, Young's modulus and elongation at break are about 87.9 MPa, 1563.9 MPa and 10.2%, respectively. It is essential that the soluble polyaniline should be appropriately treated in some suitable organic solvents before making a free-standing film. Films having lustrous, smooth surface, high density and good flexibili...

Anticorrosion performance of polyaniline nanostructures on mild steel

Different one-dimensional nanostructured polyanilines were synthesized in sulfuric acid solutions by conventional polymerization, interfacial polymerization and direct mixed reaction, respectively. The products were characterized with SEM, UV-vis and FTIR and the anticorrosion performance of products on mild steel were studied using electrochemical measurement in 3.5% NaCl aqueous solution. Results showed that the polyaniline nanofibers synthesized by direct mixed reaction have uniform morphology with diameters of 60-100 nm and more excellent protective properties than conventional aggregated polyaniline. Comparative studies revealed that the nanostructure and morphology of polyaniline could influence its anticorrosion performance. (C) 2010 Elsevier B.V. All rights reserved.

Enhanced photoresponse from the ordered microstructure of naphthalocyanine-carbon nanotube composite film

Naphthalocyanine-sensitized multi-walled carbon nanotube (NaPc-MWNT) composites have been synthesized through the pi-stacking between naphthalocyanine (NaPc) and carbon nanotubes. The resultant nanocomposites were characterized with a scanning electron microscope (SEM), a transmission electron microscope (TEM), and by UV - vis absorption and photocurrent spectra. The long-range ordering was observed in the NaPc - MWNT composites by using a TEM. The enhancement in the absorption intensity and the broadening of the absorption wavelength observed in the composite films, which were due to the attachment of NaPc on the MWNT surface, is discussed based on the measured UV - vis absorption spectra. Furthermore, the photoconductivity of the poly( 3-hexylthiophene)(PAT6) - NaPc - MWNT composite film was found to increase remarkably in the visible region and broaden towards the red regions. These new phenomena were ascribed to the larger donor/acceptor (D/A) interface and the formation of a biconsecutive D/A network structure, as discussed in consideration of the photoinduced charge transfer between PAT6 and NaPc - MWNT.

聚苯胺、聚苯胺纳米复合材料的光谱电化学研究

导电聚合物在防腐、传感和二次电池等方面具有很高的应用价值。表面增强拉曼光谱（SERS）对界面信息有较高的灵敏度和选择性，特别是原位技术可以提供详细的界面信息。我们确定了用本实验室己经很成熟的自组装膜技术对电极进行功能化修饰，再结合原位电化学SERS方法对聚苯胺的电化学初聚过程进行研究，进一步了解了聚合成膜的机理；为有目的地构造具有特殊结构和用途的聚苯胺以及聚苯胺与纳米粒子的复合功能材料提供理论依据。1．在4-ATP／金修饰电极上化学接枝制备4一琉基偶氮氨基苯单层膜；我们首先在经电化学氧化还原粗糙化处理的金电极上组装了4-ATP分子并且得到了具有较高信噪比的拉曼增强信号；继而我们又利用经典的重氮化偶联反应接枝了苯胺分子得到了稳定的具有较高电化学活性的对琉基偶氮苯单层膜。2．在4-ATP／金修饰电极上进行了苯胺电化学聚合过程的原位SERS研究；通过采用原位电化学循环伏安一表面增强拉曼光谱法，研究了在硫酸介质下苯胺在4-ATP修饰的金电极上的起始聚合情况，并与未经修饰的裸金电极进行了对比，认为：具有高度电子导电性的4-ATP分子对苯胺的聚和起到了促进作用；得到的聚苯胺薄膜继承了4-ATP分子自组装膜的有序结构，采取的是苯胺的C_4位与下层的4-ATP分子的N位进行头一尾偶联聚和。3．聚苯胺与金属和非金属纳米复合材料的制备；全部采用电化学聚合的方法，制备了聚苯胺／金纳米粒子，聚苯胺／碳纳米管，聚苯胺／碳纳米管／金纳米粒子／的复合膜。通过形貌和电化学表征，认为金纳米粒子和碳纳米管在聚苯胺膜中分布均匀，形成了比较好的复合材料，且具有良好的导电性能，有望在二次电池和传感器方面有较好的应用。

DNA-聚苯胺体系的电化学及扫描探针显微学研究

DNA-聚苯胺复合物在低维纳米材料制作、生物传感器、DNA杂交反应检测以及生物芯片开发等方面具有潜在的应用价值。鉴于此，我们在本论文中着重研究了以下两方面内容：1．利用循环伏安法研究了DNA的存在对聚苯胺电化学行为的影响。研究发现，虽然，苯胺的循环伏安聚合过程不受DNA的影响，但是DNA的存在会显著降低聚苯胺修饰电极在HCl空白溶液中循环伏安扫描时的峰电流值。初步推测可能是由于DNA分子在聚苯胺膜上的吸附阻碍了电极上电子的传递而造成的。2．通过自组装方法从水溶液中构造出了分散性良好的苯胺-DNA复合物纳米线，并以此为前驱体构造出了以DNA为模板的聚苯胺纳米线。另外，利用改进后的气流展开法可以将所得到的纳米线有序排列到基底上。用原子力显微镜对所得到的纳米线进行了表征，结果显示纳米线形貌规整、排列有序、背景清晰。

溶胶-凝胶法制备导电聚苯胺杂化材料

针对有机一无机杂化材料制备过程中致命的体积收缩问题，本论文相继选用一系列具有亲水性官能团的聚倍半硅氧化物类前驱体为基体，采用溶胶一凝胶方法，以区域限制方式把水溶性导电聚苯胺固定在三维无机网络内，获得了耐水型自支撑杂化导电膜，该自支撑膜呈现出一定的机械强度与耐磨性。同时，为了进一步增加有机、无机组分之间的作用力，获取分子级别杂化材料，本文尝试了在导电聚苯胺与无机网络之间引入共价键、离子键等较强相互作用，得到了一些有意义的结果，具体如下：（1）亲水性的倍半硅氧烷前驱体、桥联倍半硅氧烷前驱体均能与水溶性导电聚苯胺形成平整的自支撑膜，该导电膜呈现出较好的耐”水性。（2）通过一步掺杂法制备的化学键接型水溶性导电聚苯胺／无机杂化膜除显示出良好的耐水性外，其热稳定性也得到了提高，从而为耐热型导电杂化膜的开发提供了思路。（3）有机一无机组分间通过离子键接引入静电相互作用亦是提高体系相容性，获取耐水型自支撑杂化膜的另一有效的方法。但由于导电膜中含有大量的离子键，与上述两体系相比，机械强度显得稍脆。（4）带有长链状亲水基团的掺杂剂酸性磷酸酷具有很强的自组装能力，不仅能在杂化体系中指导聚苯胺纳米管的构筑，而且能通过聚合单体法直接生成大批量聚苯胺纳米管材料。

苯胺类共聚物的合成、结构与性能

本工作采用不同方法合成了一系苯胺类共聚物，并系统地研究了各种共聚物的结构和性能。揭示了以自由基阳离子聚合机理为基础的一类崭新的共聚反应的一些基本性质。采用化学氧化法使苯胺与邻早苯胺或邻甲氧基苯胺进行共聚反应通过THF/CHCl_3两步分离法获得了不同组成、不同分子量的一系列共聚物。通过研究取代基与分子量对溶解性的影响，证实共聚增溶作用最主要的是由于在分子主链上引入了取代基，增大了分子链间距离，使分子链间作用力减弱而导致溶解性增加，同时共聚物分子量较低也是原因之一。研究了分子量及取代基对聚合物热稳定性的影响，分子量增大提高了起始热分解温度，引入取代基使起始热分解温度降低，不利于提高热稳定性，原因在于热稳定性与分子间作用力关系密切。

Electrochemical polymerization and characterization of polypyrrole nanowires and nanotubules

Polypyrrole nanostructure arrays, including simultaneously large quantities of nanowires and small quantities of partially filled nanotubules have been electrochemically synthesized in home-made etched ion-track polycarbonate (PC) templates. Diameter of the prepared nanostructures varies from 45 to 320 nm with their lengths up to 30 microns. Morphological studies of these nanostructures were performed by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. While optical absorption properties were studied by ultraviolet-visible-near infrared spectrophotometry (UV-vis-NIR). It has been observed that the absorption maximum of polypyrrole shifts to the longer wavelength side as the diameter of these nanostructures (nanowires and nanotubules) increases. (C) 2010 Elsevier B.V. All rights reserved.