Theoretical investigation of van der Waals forces between solid surfaces at nanoscales

Theoretical investigation of van der Waals forces between solid surfaces at nanoscales

Kudryavtsev, Y.V.
Gelinck, E.R.M.
Fischer, H.R.
TNO Industrie en Techniek

2009

A theoretical investigation of van der Waals forces acting between two solid silicon surfaces at separations from zero to approximately 20 nm is presented. We focused our efforts on the analysis of different factors that can cause deviations from the classical pressure-distance dependence p ∼ 1/D3. It is demonstrated that a layer (oxide or water) at any of the surfaces influences the pressure up to distances, which are an order of magnitude larger than its own thickness. A jump on the p(D) curve is expected at contact of the adsorbed liquid layers. The retardation of van der Waals forces at 5 < D < 20 nm has the similar effect on the pressure as 1 nm oxide layers. At the far end of this range the pressure decreases by 30% due to the retardation. Nanoscale roughness plays a great role when the surfaces are close-to-contact, the crucial factor is the height distribution of asperities. However, their curvature and surface density are also important, as well as the amount of adsorbed water. © 2009 Elsevier B.V. All rights reserved.

Materials
Semi-empirical models and model calculations
Silicon
Silicon oxides
Surface structure
Adsorbed water
Height distribution
Liquid layer
Nano scale
Nano-scale roughness
Order of magnitude
Oxide layer
Semi-empirical models and model calculations
Solid silicon
Solid surface
Surface density
Surface structure, morphology, roughness, and topography
Theoretical investigations
Dielectric properties
Liquids
Nanostructured materials
Pressure effects
Silicon oxides
Surface morphology
Surface topography
Topography
Van der Waals forces

http://resolver.tudelft.nl/uuid:235b6782-80cc-44c1-95a7-bb6ed5b646ad

241698

0039-6028

Surface Science, 603 (16), 2580-2587

article