Journal article
Monolayer damage in XPS measurements as evaluated by independent methods
Langmuir, Vol.13(19), pp.5089-5106
Sep/1997
Abstract
The damage caused to amphiphilic n-alkane monolayers under XPS measurement conditions was assessed in a combined XPS-FTIR study supplemented by additional AFM imaging and contact angle measurements. Nine different self-assembled monolayer/substrate systems were examined, comprising a long chain silane (C-18, OTS), a short chain silane (C-1, MTS), a functional (COOH-terminated) long chain silane (C-18, NTSox), a long chain carboxylic acid (C-20, AA), and four different solid substrates (silicon, quartz, glass, and ZnSe). Significant differences were observed in the behavior of the various examined monolayer systems under identical X-ray irradiation conditions. These are interpreted in terms of effects associated with the specific mode of layer-to-surface and intralayer coupling, the size of the monolayer hydrocarbon core, and the presence of radiation-sensitive functional groups in the layer. All these factors and their influence on the degradation path followed by a particular monolayer upon exposure to the X-rays were found to be interrelated, giving rise to a variety of possible damage patterns, including an unexpected overall stabilization effect initiated by the preferential rapid loss of a labile top functional group (NTSox). XPS is shown to be insufficient as a tool for the evaluation of the radiation-induced damage in such ultrathin films, because of its insensitivity to loss of hydrogen and to structural transformations that occur without a net loss of carbon from the surface. Independent methods of surface analysis (mainly FTIR), applied in conjunction with XPS, provide a more comprehensive picture of the induced damage, thus permitting a realistic interpretation of the XPS experimental data as well as the design of improved data acquisition procedures. This could also assist in the tailoring of monolayers with predetermined degradability, for specific purposes. Finally, results of combined AFM-XPS-FTIR-contact angle measurements suggest the possible for
Details
- Title
- Monolayer damage in XPS measurements as evaluated by independent methods
- Creators
- E Frydman (null) - The Weizmann Institute of ScienceHagai Cohen (null) - 972WIS_INST___100Rivka Maoz (null) - The Weizmann Institute of ScienceJacob Sagiv (null) - The Weizmann Institute of Science
- Resource Type
- Journal article
- Publication Details
- Langmuir, Vol.13(19), pp.5089-5106; Sep/1997
- Number of pages
- 18
- Language
- English
- DOI
- https://doi.org/10.1021/la962058q
- Grant note
- We thank Dr. Kazufumi Ogawa of Matsushita Electric Ind. Co. Ltd. (Osaka) for the supply of the NTS employed in this study. The AFM imaging (Figure 13) was done by Dr. Sophie Matlis, at the Chemical Services Unit of the Weizmann Institute. This research was supported by a grant from the G.I.F., the German-Israeli Foundation for Scientific Research and Development, and by a financial contribution of the Chemical Services Unit of the Weizmann Institute. E.F. is recipient of the Eshkol fellowship, within the program of strategic scientific and technological development, the Ministry of Science and the Arts, Jerusalem.
- Record Identifier
- 993263377603596
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