Tran Henry D, Wang Yue, D'Arcy Julio M, Kaner Richard B
Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles, California 90095-1569, USA.
ACS Nano. 2008 Sep 23;2(9):1841-8. doi: 10.1021/nn800272z.
Introducing small amounts of additives into polymerization reactions to produce conducting polymers can have a profound impact on the resulting polymer morphology. When an oligomer such as aniline dimer is added to the polymerization of aniline, the nanofibers produced are longer and less entangled than those typically observed. The addition of aniline dimer can even induce nanofiber formation under synthetic conditions that generally do not favor a nanofibrillar morphology. This finding can be extended to both the synthesis of polythiophene and polypyrrole nanofibers. The traditional oxidative polymerization of thiophene or pyrrole only produces agglomerated particles. However, when minute amounts of thiophene or pyrrole oligomers are added to the reaction, the resulting polymers possess a nanofibrillar morphology. These results reveal important insights into a semirigid rod nucleation phenomenon that has hitherto been little explored. When polyaniline nucleates homogeneously, surface energy requirements necessitate the formation of ordered nuclei which leads to the directional polymerization of aniline. This ultimately leads to the one-dimensional nanofibrillar morphology observed in the final product. The synthetic procedures developed here are simple, scalable, and do not require any templates or other additives that are not inherent to the polymer.
在聚合反应中引入少量添加剂以制备导电聚合物，会对所得聚合物的形态产生深远影响。当将诸如苯胺二聚体之类的低聚物添加到苯胺的聚合反应中时，所产生的纳米纤维比通常观察到的更长且缠结更少。添加苯胺二聚体甚至可以在通常不利于纳米纤维形态的合成条件下诱导纳米纤维的形成。这一发现可以扩展到聚噻吩和聚吡咯纳米纤维的合成。噻吩或吡咯的传统氧化聚合仅产生团聚颗粒。然而，当向反应中添加微量的噻吩或吡咯低聚物时，所得聚合物具有纳米纤维形态。这些结果揭示了对一种迄今很少被探索的半刚性棒状成核现象的重要见解。当聚苯胺均匀成核时，表面能要求促使形成有序的核，这导致苯胺的定向聚合。这最终导致在最终产物中观察到一维纳米纤维形态。这里开发的合成方法简单、可扩展，并且不需要任何模板或聚合物本身不固有的其他添加剂。
