Self-assembly of rod-coil molecules into molecular length-dependent organization.
Self-assembly of rod-coil molecules into molecular length-dependent organization.
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DOI：
10.1021/ja039793q
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发表时间：
2004-03
影响因子：
15
通讯作者：
J. Ryu;Nam-Keun Oh;W. Zin;Myongsoo Lee
中科院分区：
文献类型：
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作者：
J. Ryu;Nam-Keun Oh;W. Zin;Myongsoo Lee
合成了一系列分子长度不同的棒-线圈分子（n-x，其中n表示PPO线圈中重复单元的数目，x表示棒段中苯基的数目），但具有相同的棒-线圈体积比，并通过DSC和x射线散射研究了它们的自组装行为。具有短棒圈分子（16-4）的分子除了具有层状结构外，还具有基于离散束体心对称的三维四边形结构。这种三维晶格在加热时坍塌，产生无序的胶束结构。值得注意的是，基于较长分子长度（21-5和24-6）的分子在加热时可以自组织成片层结构、四边形穿孔片层结构、二维六边形柱状结构和无序胶束结构。在29-7和32-8的情况下，分子长度的进一步增加导致三维六边形穿孔板层结构作为板层结构和四边形穿孔板层结构之间的中间结构。因此，这些系统证明了在相同的棒-线圈体积分数下，通过分子长度的微小变化，可以调节畴纳米结构，从二维连续层、长条到通过周期性穿孔层的离散束。
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.