Self-Organization of Bilayr-Forming Crystals

本研究项目的目的是了解两亲性分子在溶液中自发聚集的基本原理。为此，通过烷基链长m和n的系统变化，对含偶氮苯的两亲化合物C_nAzoC_mN^+Br^-的化学结构与双层结构之间的关系进行了深入的研究。(1)对于m-n和lt；大于或等于-gt；2的化合物，偶氮苯发色团平行并排排列，来自双分子层两侧的两亲分子相互交错。这种堆积方式称为“H-聚集体”结构。特别是对m-n=2的化合物进行了结晶，并对其结构进行了精确的分析。虽然m-n和lt；大于或等于-gt；2的化合物的铸膜层具有H-聚集结构，但其稳定性随着m-n与2之差(m-n)的增加而降低。(2)在m=5的化合物中，偶氮…更多的苯发色基团以从头到尾的方式排列，两亲分子向双层表面倾斜约30ﾟ。这种堆积方式被称为“J-聚集体”结构。这组化合物很容易结晶，每个样品都进行了分析，以获得精确的双层结构。(3)不同m和n的化合物在高温下都表现出晶体-晶体转变，其结构在较高温度下似乎类似于J-聚集结构，而与其原始聚集结构无关。(4)根据上述实验结果，得出了以下结论。疏水部分和亲水部分之间的横截面平衡是形成双层结构的最重要的驱动力。通过改变尾部(N)和间隔体(M)部分的碳原子数来控制双层结构。此外，在H-聚集态的情况下，微小的结构差异可以由奇数或偶数更少来控制

The purpose of this research project is to understand the fundamental aggregation principle when amphiphile molecules organize spontaneously in solution by themselves. To do this, the relationship between chemical structures and bilayr structures of azobenzene-containing amphiphiles C_nAzoC_mN^+Br^- were thoroughly investigated by the systematic change of alkyl chain lengths, m and n.Following results were obtained. (1) For the compounds with m-n<greater than or equal>2, azobenzene chromophores are parallely arranged in a side by side fashion and amphiphile molecules from both sides of a bilayr interdigitate each other. This packing mode was called "H-aggregate" structure. Especially, the compounds with m-n=2 were crystallized and their structures were analyzed precisely. Although cast films of compounds with m-n<greater than or equal>2 showed H-aggregation structure, their stability decreased with the increase of the difference (m-n) from 2. (2) In the case of compounds with m=5, azob … More enzene chromophores are arranged in a head to tail fashion and amphiphile molecules tilt by about 30ﾟ to the bilayr surface. This packing mode was called "J-aggregate" structure. This group of compounds was easy to crystallize and every specimen was analyzed to get precise bilayr structures. (3) Every compound with different m and n showed a crystal-crystal transition at elevated temperature and their structures at higher temperature seemed to be similar to the J-aggregation structure, independent on their original aggregation structures. (4) From the above experimental results the following conclusions were obtained. The cross-section balance between the hydrophobic part and the hydrophilic part is most important as a driving force in the formation of bilayr structures. The bilayr structure was controlled by changing the number of carbon atoms in the tail (n) and the spacer (m) part. Moreover, in the case of H-aggregation state, small structural differences could be controlled by the odd or even Less