Kwon Seungwook, Choi Youngsik, Choi Jungseok, Kang Hungu, Chung Hoeil, Noh Jaegeun
Department of Chemistry, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Republic of Korea.
Ultramicroscopy. 2008 Sep;108(10):1311-4. doi: 10.1016/j.ultramic.2008.04.035. Epub 2008 May 10.
Displacement of cyclohexanethiols (CHTs) self-assembled monolayers (SAMs) by octanethiols on Au (111) (OTs) was examined by scanning tunneling microscopy (STM) and contact angle measurements. We revealed that the fast displacement of CHT by OT takes place within a few minutes, and then displacement proceeds slowly to form the closely packed OT SAMs. The main driving force for the unusual fast displacement is due to the large increase of chemical interactions between the sulfur and gold atoms, and the van der Waals interactions between alkyl chains after displacement of CHT by OT. STM imaging clearly demonstrated the structural transitions from the (5 x 2 square root 10)R48 degrees structure of CHT SAMs to the (square root 3 x square root 3)R30 degrees or c(4 x 2) structures of OT SAMs via an intermediate phase that were often observed during alkanethiol SAM growth on gold. In this study, we found that CHT SAMs can be used as a new transient layer for the fabrication of nanostructures on a surface.
通过扫描隧道显微镜（STM）和接触角测量，研究了正辛硫醇（OTs）在金（111）表面对环己硫醇（CHTs）自组装单分子层（SAMs）的置换情况。我们发现，OT能在几分钟内快速置换CHT，之后置换过程缓慢进行，形成紧密堆积的OT SAMs。这种异常快速置换的主要驱动力是由于硫与金原子之间化学相互作用的大幅增加，以及OT置换CHT后烷基链之间的范德华相互作用。STM成像清楚地表明，CHT SAMs的（5×2√10）R48°结构通过一个在金表面烷硫醇SAM生长过程中经常观察到的中间相，转变为OT SAMs的（√3×√3）R30°或c（4×2）结构。在本研究中，我们发现CHT SAMs可作为一种新的过渡层用于在表面制备纳米结构。
