Spectroscopic study of water adsorption and desorption on/from oligo(ethylene glycol)-substituted alkanethiolate self-assembled monolayers
Adsorption and temperature-driven desorption of water (D2O) on/from the surface of oligo(ethylene glycol) (OEG)-substituted alkanethiolate self-assembled monolayers (SAMs) with a variable length of the OEG segment and variable termination (−OH or −OMe) were studied by synchrotron-based X-ray photoel...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
May 1, 2018
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| In: |
The journal of physical chemistry. C, Energy, materials, and catalysis
Year: 2018, Volume: 122, Issue: 20, Pages: 10918-10928 |
| ISSN: | 1932-7455 |
| DOI: | 10.1021/acs.jpcc.8b02514 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1021/acs.jpcc.8b02514
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| Author Notes: | Mustafa Sayin, Alexei Nefedov, and Michael Zharnikov |
| Summary: | Adsorption and temperature-driven desorption of water (D2O) on/from the surface of oligo(ethylene glycol) (OEG)-substituted alkanethiolate self-assembled monolayers (SAMs) with a variable length of the OEG segment and variable termination (−OH or −OMe) were studied by synchrotron-based X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The characteristic spectroscopic features of D2O were monitored, with a predominant signature of amorphous ice upon adsorption at 105-125 K and subsequent heating up to desorption temperature. The adsorption occurred exclusively onto the SAM surface, with a strong distortion of the spectral pattern for the first layer (for OH-terminated surfaces) and without any indication for the penetration of the D2O molecules into the hydrogel-like OEG part of the SAMs. The thickness of the ice films increased linearly with the D2O dose with the same rate for all OH-terminated SAMs and a slightly lower rate for the CH3-terminated films. The desorption of D2O in the given quasi-static temperature increase regime occurred at ∼150-155 K for all SAMs studied. Specific features of the NEXAFS spectra could be tentatively interpreted as a signature of a hydration phase, formed by the temperature-driven diffusion of the adsorbed D2O molecules into the hydrogel-like OEG part of the SAMs. |
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| Item Description: | Gesehen am 23.05.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1932-7455 |
| DOI: | 10.1021/acs.jpcc.8b02514 |