National Center for Nanoscience and Technology, Beijing 100190, PR China.
J Am Chem Soc. 2010 Sep 1;132(34):12006-12. doi: 10.1021/ja1036447.
An ordered superlattice self-assembled from monodispersed nanostructures can exhibit collective effects of its individual building blocks, a desirable property that gives rise to potential applications. However, no general method for the direct fabrication of superstructures yet exists, especially for superlattices that start from rational-designed functional molecules. Noncovalent interactions are widely used for the self-assembly of biomolecules in nature, such as various superstructures of proteins. Instead of using hydrogen bonds as driving force for the self-assembly of beta-sheet structures of peptides, pi-pi stacking interactions were used in this study to self-assemble conducting polyaniline (PANI) nanostructures and superstructures. Monodispersed crystalline PANI nanorices were prepared by using homochiral PANI as building blocks; these nanorices can further self-assemble into hexagonal microplates aligned shoulder to shoulder. PANI molecules were organized into nanorices via single-handed helical pi-pi stacking, in which the molecular plane was normal to the long axis of the nanorices. Electrical transport measurements showed the anisotropic characteristics of self-assembled nanorices and their superstructures, which were due to the directional transport barrier in the nanorices and the structural defects at the interfaces between neighboring nanorices. As chiral PANI and peptides have similar self-assembly behaviors, the method used in this study is greatly expected to be applicable to other chemical and biochemical building blocks.
由单分散纳米结构自组装的有序超晶格可以表现出其各个组成部分的集体效应，这是一种理想的特性，为潜在的应用提供了可能性。然而，目前还没有一种通用的方法可以直接制造超结构，特别是对于那些从合理设计的功能分子开始的超晶格。非共价相互作用广泛用于自然界中生物分子的自组装，例如蛋白质的各种超结构。在本研究中，我们使用π-π堆积相互作用代替氢键作为肽β-折叠结构自组装的驱动力，来自组装导电聚苯胺（PANI）纳米结构和超结构。通过使用手性 PANI 作为构建块，制备了单分散的结晶 PANI 纳米棒；这些纳米棒可以进一步自组装成六边形微板，肩并肩排列。PANI 分子通过单手螺旋 π-π 堆积组织成纳米棒，其中分子平面垂直于纳米棒的长轴。电输运测量显示了自组装纳米棒及其超结构的各向异性特征，这是由于纳米棒中的定向输运势垒和相邻纳米棒之间界面处的结构缺陷所致。由于手性 PANI 和肽具有相似的自组装行为，因此本研究中使用的方法有望应用于其他化学和生化构建块。
