Interaction of silane coupling agents with the TiO{sub 2}(110) surface
- Univ. of Washington, Seattle, WA (United States)
The interactions of prototypical silane coupling agents with a clean and hydroxyl-predosed TiO{sub 2}(110) single-crystal surface have been studied using surface spectroscopic techniques. The adsorption and reactions of vinyltriethoxysilane (VTES), diethyldiethoxysilane (DEDS), and (aminopropyl)triethoxysilane (APS) were studied by means of temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Even in the absence of surface water or hydroxyls, VTES dissociates rapidly to form Si(OEt)-(CH=CH{sub 2} ){sub s} and two OEt{sub s}, where Et = C{sub 2}H{sub 5} and `s` refers to surface species. The DEDS similarly dissociates to produce a mixture of SiEt{sub 2,s}, EtOSiEt{sub 2,s}, and one to two OEt{sub s}. When hydroxyls are predosed on the surface, they react with any Ti{sup 4+}-bound EtO- ligands formed in the initial decomposition of VTES and DEDS to produce ethanol gas at nearly 350 K. Thus, the main function of the hydroxyls is to clear Ti{sup 4+} sites of ethoxy groups, not to act as sites for the initial attachment of the silane to the surface. Neither TPD nor XPS data indicated that APS dissociated to a measurable extent on the TiO{sub 2}(110) surface. 31 refs., 6 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 159696
- Journal Information:
- Langmuir, Vol. 11, Issue 11; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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