Thiol鈥揈ne鈥揟hiol Photofunctionalization of Thiolated Monolayers with Polybutadiene and Functional Thiols, Including Thiolated DNA

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• 作者：Nitesh Madaan ; Aaron Terry ; John Harb ; Robert C. Davis ; Helmut Schlaad ; Matthew R. Linford
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：November 24, 2011
• 年：2011
• 卷：115
• 期：46
• 页码：22931-22938
• 全文大小：923K
• 年卷期：v.115,no.46(November 24, 2011)
• ISSN：1932-7455

文摘

Self-assembly of organic thiols is the most common way to introduce functional groups onto gold surfaces. Although the gold鈥搒ulfur (Au鈥揝) bond is moderately strong (45 kcal/mol), it is also prone to oxidation, which substantially weakens the Au鈥揝 interaction. In this work, we describe the creation of more robust molecular assemblies on gold. As a first step, a thiolated monolayer is prepared on gold with an 伪,蠅-dithiol. Experiments are also reported for a mercaptosilane monolayer on silicon dioxide. An oligomer of polybutadiene (PBd) was then tethered to these surfaces using thiol鈥揺ne chemistry. Residual groups on the PBd are then reacted with thiols, including octadecanethiol (ODT), 1H,1H,2H,2H-perfluoroalkanethiol, and a thiol-terminated 25-mer of DNA. Little nonspecific adsorption of a non-thiolated DNA oligomer was observed. Surface characterization was performed with X-ray photoelectron spectroscopy (XPS), contact angle goniometry, time-of-flight secondary ion mass spectrometry (ToF-SIMS), and spectroscopic ellipsometry. A thiol鈥揼old monolayer and an analogous assembly of the same thiol tethered to gold through PBd on a dithiol monolayer were both exposed to air and light for 2 weeks and then rinsed with water. The monolayer on gold was removed in this process, while the thiol in the assembly appeared unaffected.