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Mengistu TZ, Goel V, Horton JH, et al. Chemical force titrations of functionalized Si(111) surfaces. Langmuir. 2006;22(12):5301-7doi: 10.1021/la052776p.
Mengistu, T. Z., Goel, V., Horton, J. H., & Morin, S. (2006). Chemical force titrations of functionalized Si(111) surfaces. Langmuir : the ACS journal of surfaces and colloids, 22(12), 5301-7. https://doi.org/10.1021/la052776p
Mengistu, Tadesse Z, et al. "Chemical force titrations of functionalized Si(111) surfaces." Langmuir : the ACS journal of surfaces and colloids vol. 22,12 (2006): 5301-7. doi: https://doi.org/10.1021/la052776p
Mengistu TZ, Goel V, Horton JH, Morin S. Chemical force titrations of functionalized Si(111) surfaces. Langmuir. 2006 Jun 06;22(12):5301-7. doi: 10.1021/la052776p. PMID: 16732656.
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Langmuir. 2006 Jun 06;22(12):5301-7. doi: 10.1021/la052776p.

Chemical force titrations of functionalized Si(111) surfaces.

Langmuir : the ACS journal of surfaces and colloids

Tadesse Z Mengistu, Vishya Goel, J Hugh Horton, Sylvie Morin

Affiliations

  1. Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario, Canada, M3J 1P3.

PMID: 16732656 DOI: 10.1021/la052776p

Abstract

Chemical force titrations-plots of the adhesive force between an atomic force microscope tip and sample as a function of pH-were acquired on alkyl monolayer-derivatized Si(111) surfaces. Gold-coated AFM tips modified with thioalkanoic acid self-assembled monolayers (SAM) were employed. Alkyl monolayer-derivatized Si(111) surfaces terminated with methyl, carboxyl, and amine groups were produced via hydrosilylation reactions between 1-alkene reagents and H-terminated silicon. The functionalized surfaces were characterized using standard surface science techniques (AFM, FTIR, and XPS). Titration of the methyl-terminated surface using the modified (carboxyl-terminated) atomic force microscope tip resulted in a small pH-independent hydrophobic interaction. Titration of the amine-terminated surface using the same tip resulted in the determination of a surface pKa of 5.8 for the amine from the pH value from the maximum in the force titration curve. A pK(1/2) of 4.3 was determined for the carboxyl-terminated Si(111) in a similar way. These results will be discussed in relation to the modified Si(111) surface chemistry and organic layer structure, as well as with respect to existing results on Au surfaces modified with SAMs bearing the same functional groups.

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