Muneyasu Riku, Yamada Takashi, Akai-Kasaya Megumi, Kato Hiroyuki S
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Phys Chem Chem Phys. 2022 Sep 21;24(36):22222-22230. doi: 10.1039/d2cp03356a.
The self-assembly of heterogeneous bilayers on Au substrates was investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and infrared reflection absorption spectroscopy (IRAS). The formation of a well-defined bilayer including different types of functional groups would be one of the desired goals to create varying surface functionalities. In this study, we examined the assembly of a hydrogen-bonded molecular layer to another functional alkanethiolate self-assembled monolayer (SAM) on the Au(111) surface. The chemical properties and bond strength of the hydrogen bonds at the interlayer differ from those of the Au-S bonds at the anchor of thiolate SAMs, therefore the adsorbed molecules are expected to form a stratified bilayer. In this study, on one hand, we revealed that imidazole-terminated alkanethiolate SAMs (Im-SAMs) have an atomically smooth topography but chemically inhomogeneous Au-S anchors, rather incomplete than -alkanethiolate SAMs, on the Au(111) surface. On the other hand, we confirmed the self-assembly of the heterogeneous bilayers including Im-SAMs on the Au(111) surface, even in a mixed solution containing two types of molecules. These results show that the self-assembly of the bilayer stratified by H bonds and Au-S bonds is flexible and adaptable.
利用原子力显微镜（AFM）、X射线光电子能谱（XPS）和红外反射吸收光谱（IRAS）研究了金基底上异质双层的自组装过程。形成包含不同类型官能团的明确双层结构将是实现不同表面功能的理想目标之一。在本研究中，我们考察了氢键分子层与金（111）表面上另一种功能性硫醇盐自组装单分子层（SAM）的组装情况。层间氢键的化学性质和键强度不同于硫醇盐SAM锚定处的金 - 硫键，因此预计吸附分子会形成分层双层结构。在本研究中，一方面，我们发现咪唑封端的硫醇盐SAM（Im - SAMs）在金（111）表面具有原子级光滑的形貌，但化学性质不均匀的金 - 硫锚定，不如 - 硫醇盐SAM完整。另一方面，我们证实了即使在含有两种分子的混合溶液中，金（111）表面上包括Im - SAMs的异质双层也能自组装。这些结果表明，由氢键和金 - 硫键分层的双层自组装具有灵活性和适应性。
