Single-Molecule Bond-Rupture Force Analysis of Interactions between AFM Tips and Substrates Modified with Organosilanes

• Published in: Analytical chemistry (Washington) 1997-07, Vol.69 (14), p.2855-2861
• Main Authors: Wenzler, L. A, Moyes, G. L, Olson, L. G, Harris, J. M, Beebe, T. P
• Format: Article
• Language: English
• Subjects: Chemical bonds; Chemistry; Exact sciences and technology; General and physical chemistry; General, apparatus; Surface and interface chemistry; Surface physical chemistry
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac961065g

Recent atomic force microscopy studies have probed specific chemical interactions between the tip and the surface. A statistical method that produces information about the magnitude of single-molecule bond-rupture forces has been developed in our laboratories. This paper describes the extension of this technique to the study of single-molecule bond-rupture forces for organosilane coupling agents covalently attached to hydroxyl-bearing surfaces. Since both the tip and the surface can be modified by functionalized organosilanes, studies of a variety of tip−surface interactions have been possible. We were able to verify the adsorption of a variety of organosilanes on both the tip and surface using X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Interactions that were studied and quantified include van der Waals interactions between bromine-terminated silanes and the hydrophobic interactions between methyl-terminated silanes on the tip and surface.