Logo image
Back
Surface forces: Surface roughness in theory and experiment
Journal article   Open access   Peer reviewed

Surface forces: Surface roughness in theory and experiment

D.F. Parsons, R.B. Walsh and V.S.J. Craig
The Journal of Chemical Physics, Vol.140(16)
2014
DOI: https://doi.org/10.1063/1.4871412
pdf
suface_roughness_in_theory_and_experiment.pdfDownloadView
Published (Version of Record) Open Access
url
Link to Published Version *Subscription may be requiredView

Abstract

A method of incorporating surface roughness into theoretical calculations of surface forces is presented. The model contains two chief elements. First, surface roughness is represented as a probability distribution of surface heights around an average surface height. A roughness-averaged force is determined by taking an average of the classic flat-surface force, weighing all possible separation distances against the probability distributions of surface heights. Second the model adds a repulsive contact force due to the elastic contact of asperities. We derive a simple analytic expression for the contact force. The general impact of roughness is to amplify the long range behaviour of noncontact (DLVO) forces. The impact of the elastic contact force is to provide a repulsive wall which is felt at a separation between surfaces that scales with the root-mean-square (RMS) roughness of the surfaces. The model therefore provides a means of distinguishing between "true zero," where the separation between the average centres of each surface is zero, and "apparent zero," defined by the onset of the repulsive contact wall. A normal distribution may be assumed for the surface probability distribution, characterised by the RMS roughness measured by atomic force microscopy (AFM). Alternatively the probability distribution may be defined by the histogram of heights measured by AFM. Both methods of treating surface roughness are compared against the classic smooth surface calculation and experimental AFM measurement.

Details

Metrics

311 File views/ downloads
174 Record Views
66 Times Cited - Web of Science

InCites Highlights

These are selected metrics from InCites Benchmarking & Analytics tool, related to this output

Citation topics
2 Chemistry
2.167 Microelectromechanical Systems
2.167.555 Atomic Force Microscopy
Web Of Science research areas
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
ESI research areas
Chemistry
Logo image