Alkyl and Alkoxyl Monolayers Directly Attached to Silicon: Chemical Durability in Aqueous Solutions

详细信息    查看全文

• 作者：Hikaru Sano ; Hajime Maeda ; Takashi Ichii ; Kuniaki Murase ; Kei Noda ; Kazumi Matsushige ; Hiroyuki Sugimura
• 刊名：Langmuir
• 出版年：2009
• 出版时间：May 19, 2009
• 年：2009
• 卷：25
• 期：10
• 页码：5516-5525
• 全文大小：1068K
• 年卷期：v.25,no.10(May 19, 2009)
• ISSN：1520-5827

文摘

For practical application of self-assembled monolayers (SAMs), knowledge of their chemical durability in acidic or basic solutions is important. In the present work, a series of SAMs directly immobilized on a silicon (111) surface through Si−C or Si−O−C covalent bonds without a native oxide layer were prepared by thermally activated chemical reactions of a hydrogen-terminated Si(111) substrate with linear molecules, i.e., 1-hexadecene, 1-hexadecanol, 1-dodecanol, and n-dodecanal, to investigate the durability of the SAMs to HF and Na₂CO₃ solutions. While grazing incidence X-ray reflectivity measurements showed that all the as-prepared SAMs had almost the same film density and molecular coverage, keeping the original step and terrace structure of Si(111) as is observed by atomic force microscopy, they gave different degradation behaviors, i.e., pitting and concomitant surface roughening in both solutions. 1-Hexadecene SAM was stable against immersion in both solutions, while the other SAMs were damaged within 60 min, most likely due to the difference in chemical bonding modes at the SAM/Si interface, i.e., Si−C and Si−O−C.