Olefin-Bridged Bidentate Adsorbates for Generating Self-Assembled Monolayers on Gold
| Autor: | Maria D. Marquez, T. Randall Lee, Mario A Gonzalez, Siwakorn Sakunkaewkasem |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Olefin fiber
Denticity Materials science Dithiol Self-assembled monolayer Surfaces and Interfaces Hexadecane Condensed Matter Physics Contact angle Crystallography chemistry.chemical_compound chemistry X-ray photoelectron spectroscopy Monolayer Electrochemistry General Materials Science Spectroscopy |
| Zdroj: | Langmuir : the ACS journal of surfaces and colloids. 36(36) |
| ISSN: | 1520-5827 |
| Popis: | A series of custom-designed olefin-bridged bidentate adsorbates composed of an olefin group linking symmetrical hydrocarbon moieties of varying chain lengths was synthesized and used for the preparation of self-assembled monolayers (SAMs) on gold. The structures of the adsorbates are in the form Z-[CH3(CH2)m]2(C═C)[CH2SH]2 (OBCnSH) where m = 12-15 and n = m + 3 (OBC15SH, OBC16SH, OBC17SH, and OBC18SH). The influence of the olefin linker on the structural and interfacial properties of the SAMs was investigated and compared to SAMs formed from analogous n-alkanethiols. Characterization techniques included ellipsometry, X-ray photoelectron spectroscopy (XPS), polarization modulation-infrared reflection-adsorption spectroscopy (PM-IRRAS), and contact angle measurements. The OBCnSH SAMs exhibited ellipsometric thicknesses that were similar to their monodentate counterparts, suggesting that the new olefin-bridged adsorbates pack similarly to the monodentate analogs. Characterization by PM-IRRAS revealed that the OBCnSH SAMs were as conformationally ordered as those derived from the reference n-alkanethiols with the exception of the adsorbate with the shortest chain length OBC15SH, which exhibited low coverage and a liquid-like structure. Unlike the SAMs derived from the n-alkanethiols, the OBCnSH SAMs failed to exhibit "odd-even" effects. However, the OBCnSH SAMs displayed similar hexadecane contact angles as their n-alkanethiol counterparts with the exception of OBC15SH, which exhibited markedly diminished hexadecane contact angles. The similar structural and interfacial properties of the OBCnSH SAMs, when compared to analogous n-alkanethiol SAMs, render the molecular architecture of the olefin-bridged dithiol as a robust platform for the synthesis of adsorbates with two chemically distinct tailgroups for use in the preparation and study of phase-incompatible "conflicted" interfaces. |
| Databáze: | OpenAIRE |
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