Zhang Xuetong, Zhang Jin, Song Wenhui, Liu Zhongfan
Key Laboratory for the Physics and Chemistry of Nanodevices, Centre for Nanoscale Science and Technology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
J Phys Chem B. 2006 Jan 26;110(3):1158-65. doi: 10.1021/jp054335k.
Wire-, ribbon-, and sphere-like nanostructures of polypyrrole have been synthesized by solution chemistry methods in the presence of various surfactants (anionic, cationic, or nonionic surfactant) with various oxidizing agents [ammonium persulfate (APS) or ferric chloride (FeCl3), respectively]. The surfactants and oxidizing agents used in this study have played a key role in tailoring the nanostructures of polypyrrole during the polymerization. It is inferred that the lamellar structures of a mesophase are formed by self-assembly between the cations of a long chain cationic surfactant [cetyltrimethylammonium bromide (CTAB) or dodeyltrimethylammonium bromide (DTAB)] and anions of oxidizing agent APS. These layered mesostructures are presumed to act as templates for the formation of wire- and ribbon-like polypyrrole nanostructures. In contrast, if a short chain cationic surfactant octyltrimethylammonium bromide (OTAB) or nonionic surfactant poly(ethylene glycol) mono-p-nonylphenyl ether (Opi-10) is used, sphere-like polypyrrole nanostructures are obtained, whichever of the oxidizing agents mentioned above is used. In this case, micelles resulting from self-assembly among surfactant molecules are envisaged to serve as the templates while the polymerization happens. It is also noted that, if anionic surfactant sodium dodeyl surfate (SDS) is used, no characteristic nanostructures of polypyrrole were observed. This may be attributed to the doping effect of anionic surfactants into the resulting polypyrrole chains, and as a result, micelles self-assembled among surfactant molecules are broken down during the polymerization. The effects of monomer concentration, surfactant concentration, and surfactant chain length on the morphologies of the resulting polypyrrole have been investigated in detail. The molecular structures, composition, and electrical properties of the nanostructured polypyrrole have also been investigated in this study.
通过溶液化学方法，在各种表面活性剂（阴离子、阳离子或非离子表面活性剂）存在的情况下，分别使用各种氧化剂（过硫酸铵（APS）或氯化铁（FeCl₃））合成了聚吡咯的线状、带状和球状纳米结构。本研究中使用的表面活性剂和氧化剂在聚合过程中对聚吡咯纳米结构的定制起到了关键作用。据推测，中间相的层状结构是由长链阳离子表面活性剂[十六烷基三甲基溴化铵（CTAB）或十二烷基三甲基溴化铵（DTAB）]的阳离子与氧化剂APS的阴离子之间的自组装形成的。这些层状介观结构被认为是线状和带状聚吡咯纳米结构形成的模板。相反，如果使用短链阳离子表面活性剂辛基三甲基溴化铵（OTAB）或非离子表面活性剂聚（乙二醇）单对壬基苯基醚（Opi - 10），无论使用上述哪种氧化剂，都会得到球状聚吡咯纳米结构。在这种情况下，设想表面活性剂分子之间自组装产生的胶束在聚合发生时充当模板。还注意到，如果使用阴离子表面活性剂十二烷基硫酸钠（SDS），则未观察到聚吡咯的特征纳米结构。这可能归因于阴离子表面活性剂对所得聚吡咯链的掺杂效应，结果，表面活性剂分子之间自组装的胶束在聚合过程中被分解。详细研究了单体浓度、表面活性剂浓度和表面活性剂链长对所得聚吡咯形态的影响。本研究还对纳米结构聚吡咯的分子结构、组成和电学性质进行了研究。
