Study of Self-Assembling Mechanims of Thiol-Self-Assembled Monolayers

硫醇自组装单层膜的自组装机制研究

基本信息

批准号：
11640576
负责人：
KONDOH Hiroshi
金额：
$ 2.37万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The purpose of this research proposal is to understand microscopic mechanism of molecular self-assembly via. investigating formation process of self-assembled monolayers of thiol and related molecules by the use of STM and XAFS.In particular, we have been focusing on effects of molecule-substrate interactions on the self-assembly. The molecular orientation and the interface structure during self-assembling process have been investigated for different substrates (Au, Ag, Cu, O/Cu, Si). From systematic comparison for these substrates, we found three important factors to form well-ordered structures ; (1) sufficient molecular density, (2) surface diffusion and (3) consistency between intralayer and interface structures. It needs for achieving a well-ordered structure to satisfy all the three factors. We also found that the adsorption process is the rate-limiting step if the factor (1) is relatively important compared to the other factors while the diffusion process is the rate-limiting on … More e if the factor (2) is crucial. Another focusing point is effects of change in intermolecular interactions when introducing functional groups to the end of the alkanethiol molecules. Particularly, we have investigated self-assembly of thiophene- and porphyrin-introduced alkanethiols on gold substrates. In case of thiophene-introduced one, since the structure consistency as mentioned as factor (3) changes depending on molecular density, the self-assembly was found to take place only for a certain coverage range. In case of porphyrin-introduced molecules they exhibit no self-assembly unless the thiol group is spatially separated from the porphyrin moiety via.inserting long alkyl chains, because the large porphyrin moiety prevents the thiol group from having access to the substrate due to steric hindrance, which results in lower molecular density. Furthermore, we have investigated self-assembly of chalcogenophenes, of which structures are totally different from thiol, and found that selenophene (C_4H_4Se) forms a highly-ordered structure. Less

该研究建议的目的是了解分子自组装的微观机制。通过使用STM和XAFS的使用，研究了硫醇和相关分子的自组装单层的形成过程，尤其是我们一直专注于分子 - 底物相互作用对自组装的影响。已经研究了不同底物（AU，AG，Cu，O/Cu，Si）的自组装过程中分子方向和界面结构。从这些底物的系统比较中，我们发现了三个重要因素形成有序结构的结构。（1）足够的分子密度，（2）表面扩散和（3）内部和界面结构之间的一致性。它需要实现井井有条的结构来满足所有三个因素。我们还发现，如果因子（1）与其他因素相比相对重要，而差异过程是限制速率（如果因素（2）至关重要，则差异过程是限制的，则添加吸附过程是限制步骤。另一个重点点是，将官能团引入烷烃分子的末端时，分子间相互作用的变化的影响。部分地，我们研究了金底物上噻吩和卟啉引入的烷硫醇的自组装。如果噻吩引入的是一个，因为所述因子（3）的结构一致性取决于分子密度，因此发现自组装仅在一定的覆盖范围内进行。如果卟啉引入的分子，除非硫醇基团通过空间分离与卟啉部分分离。此外，我们已经研究了墨西哥基因的自组装，其中结构与硫醇完全不同，发现硒烯（C_4H_4SE）形成了高度排序的结构。较少的