Chemical, electrochemical, and structural stability of low-density self-assembled monolayers
The stability of low-density self-assembled monolayers of mercaptohexadecanoic acid on gold is studied under a variety of storage conditions--air at room temperature, argon at room temperature and 4 degrees C, and ethanol at room temperature. The structural monotony of the low-density monolayers was...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 23(2007), 20 vom: 25. Sept., Seite 10184-9 |
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| Format: | Article |
| Langue: | English |
| Publié: |
2007
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. Electrolytes Solutions |
| Résumé: | The stability of low-density self-assembled monolayers of mercaptohexadecanoic acid on gold is studied under a variety of storage conditions--air at room temperature, argon at room temperature and 4 degrees C, and ethanol at room temperature. The structural monotony of the low-density monolayers was assessed by monitoring the alkyl chains of LDSAMs by grazing-angle Fourier transform infrared spectroscopy as a function of time. Independently of the storage conditions, both symmetric and asymmetric methylene stretches at 2923 and 2852 cm-1 decreased after 4 weeks to 2919 and 2849 cm-1, respectively. These data suggest an increased ordering of the alkyl chains that is distinctly different from that of conventional high-density monolayers of mercaptohexadecanoic acid included as a reference in this study. As a further extension of this observation, the electrochemical barrier properties of the low-density monolayers were assessed by electrochemical impedance spectroscopy and did not change significantly for any of the storage conditions over a period of 4 weeks. Moreover, X-ray photoelectron spectroscopy was used to assess the chemical changes in the low-density monolayers over time. The chemical composition was essentially unaltered for all storage conditions. Specifically, oxidation of the sulfur headgroup, a common cause of monolayer degradation, was excluded for all test conditions on the basis of XPS analysis. This study confirms excellent storage stability for low-density monolayers under commonly used storage conditions and bridges an important technological gap between these systems and conventional high-density systems |
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| Description: | Date Completed 13.11.2007 Date Revised 23.10.2023 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |