| Autor: |
He, Mingyan, Szuchmacher Blum, Amy, Aston, D. Eric, Buenviaje, Cynthia, Overney, René M., Luginbu¨hl, Reto |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 1/15/2001, Vol. 114 Issue 3, 2 Diagrams, 5 Graphs |
| Abstrakt: |
This article discusses capillary forces measured by scanning force microscopy (SFM), which, as recently reported, show a discontinuous behavior at a low relative humidity between 20% and 40% depending on the solid surfaces. A capillary force discontinuity is very interesting in terms of a possible phase change or restructuring transition of bulk water in the interfacial solid-liquid region. Unfortunately, we have found that SFM measurements show an inherent weakness in the determination of the origin of the forces that are obtained during pull-off measurements. This article critically discusses the origin of the adhesive interactions as a function of relative humidity with chemically modified probing surfaces. Our measurements indicate that force discontinuities in pull-off measurements are strongly affected by the inability of the liquid to form capillary necks below a critical threshold in relative humidity. In the course of this article, we will discuss roughness effects on capillary forces and provide a modified capillary force equation for asperity nanocontacts. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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