Ryu Ja-Hyoung, Oh Nam-Keun, Zin Wang-Cheol, Lee Myongsoo
Center for Supramolecular Nano-Assembly and Department of Chemistry, and Yonsei University, Seoul 120-749, Korea.
J Am Chem Soc. 2004 Mar 24;126(11):3551-8. doi: 10.1021/ja039793q.
A series of rod-coil molecules (n-x, where n represents the number of repeating units in a PPO coil and x the number of phenyl groups in a rod segment) with variation in the molecular length, but an identical rod to coil volume ratio was synthesized, and their self-assembling behavior was investigated by using DSC and X-ray scatterings. The molecule with a short rod-coil molecule (16-4) shows a 3-D tetragonal structure based on a body-centered symmetry of the discrete bundles in addition to a lamellar structure. This 3-D lattice, on heating, collapses to generate a disordered micellar structure. Remarkably, the molecules based on longer molecular length (21-5 and 24-6) were observed to self-organize into, on heating, lamellar, tetagonally perforated lamellar, 2-D hexagonal columnar and finally disordered micellar structures. Further increase in the molecular length as in the case of 29-7 and 32-8 induces a 3-D hexagonally perforated lamellar structure as an intermediate structure between the lamellar and tetragonally perforated lamellar structures. Consequently, these systems demonstrate the ability to regulate the domain nanostructure, from 2-dimensionally continuous layers, long strips to discrete bundles via periodic perforated layers by small changes in the molecular length, at an identical rod-to-coil volume fraction.
合成了一系列分子长度不同但棒状与线圈状体积比相同的棒-线圈分子（n-x，其中n代表聚苯醚（PPO）线圈中的重复单元数，x代表棒状链段中的苯基数量），并通过差示扫描量热法（DSC）和X射线散射研究了它们的自组装行为。短棒-线圈分子（16-4）的分子除了具有层状结构外，还基于离散束的体心对称性呈现三维四方结构。这种三维晶格在加热时会坍塌，形成无序的胶束结构。值得注意的是，观察到基于较长分子长度（21-5和24-6）的分子在加热时会自组装成层状、四方穿孔层状、二维六方柱状，最终形成无序的胶束结构。分子长度进一步增加，如29-7和32-8的情况，会诱导形成三维六方穿孔层状结构，作为层状和四方穿孔层状结构之间的中间结构。因此，这些体系展示了在相同的棒状与线圈状体积分数下，通过分子长度的微小变化，能够将畴纳米结构从二维连续层、长条状调节为离散束，途径是通过周期性穿孔层。
