Tang Zhexiong, Padmawar Prashant A, Canteenwala Taizoon, Gao Yuan, Watkins Erik, Majewski Jaroslaw, Chiang Long Y, Wang Hsing-Lin
Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Langmuir. 2006 Jun 6;22(12):5366-73. doi: 10.1021/la060083i.
A novel amphiphilic oligo(ethylene glycol)-C60-hexadecaaniline (A16) tricomponent conjugate, C60>(A16-EG43), possessing a well-defined number of repeating aniline donor units and a hydrophilic ethylene glycol oligomer chain was synthesized. The compound is composed of a covalently bound donor-acceptor chromophore structure. Molecular self-assembly of C60>(A16-EG43) at the air-water interface formed a densely packed Langmuir monolayer with all highly hydrophobic fullerene cages located above the liquid interface. The monolayer can then be transferred onto a glass substrate via Langmuir-Blodgett (LB) deposition. LB multilayered thin films formed by multiple deposition of the monolayer yielded broadened optical absorption peaks extending beyond 600 nm into the 950 nm region, suggesting strong intermolecular interactions among the C60 cages and the A16 moieties. An X-ray reflectometry study clearly reveals that the Langmuir film at the air-water interface consists of a C60 top layer and a bottom layer containing hexcadecaaniline and oligo(ethylene glycol) with gradually decreasing electron density over a distance of approximately 130 A above bulk water. The pressure isotherm shows that the packing density of the C60>(A16-EG43) monolayer, corresponding to a molecular area of approximately 95 A2/molecule, is similar to that of the surface area of the C60 monolayer. This result suggests that C60 packing plays a dominant role in guiding the formation of the monolayer structure. Further photoexcitation of hexadecaaniline moieties of aligned (C60>)-A16 layers by a flash light source induces cross linking between adjacent A16 segments forming an interlinked A16 array. Our results have demonstrated a unique fabrication method for preparing the aligned donor-acceptor array using strong intermolecular interactions between fullerenes as the molecular orientation guiding force in the Langmuir-Blodgett technique.
合成了一种新型两亲性低聚乙二醇-C60-十六苯胺（A16）三组分共轭物C60>(A16-EG43)，其具有确定数量的重复苯胺供体单元和一条亲水性乙二醇低聚物链。该化合物由共价结合的供体-受体发色团结构组成。C60>(A16-EG43)在空气-水界面的分子自组装形成了一个紧密堆积的朗缪尔单分子层，所有高度疏水的富勒烯笼位于液体界面上方。然后可以通过朗缪尔-布洛杰特（LB）沉积将该单分子层转移到玻璃基板上。通过单分子层的多次沉积形成的LB多层薄膜产生了拓宽的光吸收峰，延伸至600nm以上进入950nm区域，这表明C60笼与A16部分之间存在强烈的分子间相互作用。X射线反射测量研究清楚地表明，空气-水界面的朗缪尔膜由一个C60顶层和一个包含十六苯胺和低聚乙二醇的底层组成，在距本体水约130埃的距离内电子密度逐渐降低。压力等温线表明，C60>(A16-EG43)单分子层的堆积密度对应于约95埃2/分子的分子面积，与C60单分子层的表面积相似。该结果表明C60堆积在引导单分子层结构形成中起主导作用。用闪光光源对排列的（C60>）-A16层的十六苯胺部分进行进一步光激发，可诱导相邻A16链段之间交联，形成相互连接的A16阵列。我们的结果展示了一种独特的制备方法，即在朗缪尔-布洛杰特技术中利用富勒烯之间的强分子间相互作用作为分子取向引导力来制备排列的供体-受体阵列。
