Chemical Sciences & Technology Division, National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram-695019, Kerala, India.
J Phys Chem B. 2010 Jan 21;114(2):728-36. doi: 10.1021/jp909016r.
We report a unique supramolecular organogel template approach for conducting polyaniline nanomaterials. A novel organogel based on sulfonic acid dopant was designed and developed from renewable resource 3-pentadecyl phenol via ring-opening of 1,4-butane sultone. The amphiphilic dopant molecule formed thermo-reversible supramolecular organogel in highly polar solvents like alcohols. The self-assembled fibril network morphology of the gel was confirmed by scanning electron microscopy (SEM) and atomic force microscopy. Transmission electron microscopy (TEM) revealed that the inner part of the fibrous gel is nanotubular with the pore diameter of approximately 75 nm. The organogel nanotubular morphology was retained even in the presence of aniline+dopant complex, and the aniline monomers occupied the hydrophobic nanopockets provided by the amphiphilic dopant. The chemical oxidative polymerization of the dopant+aniline organogel template produced well-defined polyaniline nanofibers. The polymerization was carried out at various temperatures to establish the role of the physical state and stability of the organogel on the morphology. The sulfonic acid molecule acts both as self-assembled molecular template for the synthesis of polymer nanomaterial as well as anionic counterpart for stabilizing the positively charged conducting polymer chains. The gel template played a pivotal role in directing polyaniline chains to form nanofibers and also manipulating the number of other properties such as conductivity, solubility, percent crystallinity, and solid-state ordering, etc. Temperature-dependent electrical conductivity measurements revealed that the nanomaterials showed typical linear ohmic behavior and also followed the 3-D VRH model at elevated temperatures.
我们报告了一种独特的超分子有机凝胶模板方法，用于制备聚苯胺纳米材料。一种新型的基于磺酸掺杂剂的有机凝胶是通过 1,4-丁烷砜的开环反应从可再生资源 3-十五烷基苯酚设计和开发的。两亲性掺杂剂分子在极性溶剂如醇中形成热可逆超分子有机凝胶。扫描电子显微镜（SEM）和原子力显微镜（AFM）证实了凝胶的自组装纤维网络形态。透射电子显微镜（TEM）显示，纤维凝胶的内部是具有约 75nm 孔径的纳米管状。即使存在苯胺+掺杂复合物，有机凝胶纳米管形态也得以保留，并且苯胺单体占据了两亲性掺杂剂提供的疏水性纳米口袋。掺杂+苯胺有机凝胶模板的化学氧化聚合产生了定义良好的聚苯胺纳米纤维。聚合在不同温度下进行，以确定有机凝胶的物理状态和稳定性对形态的作用。磺酸分子既可以作为聚合物纳米材料合成的自组装分子模板，也可以作为稳定带正电荷的导电聚合物链的阴离子对应物。凝胶模板在指导聚苯胺链形成纳米纤维方面起着关键作用，并且还可以控制其他一些性质，如导电性、溶解度、结晶度百分比和固态有序性等。温度依赖性电导率测量表明，纳米材料表现出典型的线性欧姆行为，并在高温下也遵循 3-D VRH 模型。
