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Physio-chemical hydrodynamic mechanism underlying the formation of thin adsorbed boundary films
journal contribution
posted on 2013-10-14, 08:33 authored by W.W.F. Chong, M. Teodorescu, Homer RahnejatThe formation of low shear strength surface-adhered thin films mitigates
excessive friction in mixed or boundary regimes of lubrication. Tribo-films are
formed as a consequence of molecular chemical reactions with the surfaces. The
process is best viewed in the context of a lubricant-surface system. Therefore, it is
usually surmised that the adsorption of lubricant molecular species to the contact
surfaces is underlying to the formation of ultra-thin lubricant films. The paper
considers contact between smooth surfaces at close separation. This may be
regarded as the contact of a pair of asperity summits, whose dimensions, however
small, are far larger than the size of fluid molecules within the conjunction. In
such diminishing separations the constraining effect of relatively smooth solid
barriers causes oscillatory solvation of fluid molecules. This effect accounts for
the conjunctional load capacity but does not contribute to mitigating friction,
except when molecular adsorption is taken into account with long chain
molecules which tend to inhibit solvation. The paper presents an analytical
predictive model based on the Ornstein–Zernike method with the Percus–Yevick
approximation of a narrow interaction potential between conjunctional
composition. The predictions confirm the above stated physical facts in
a fundamental manner.
Funding
The authors acknowledge the support and sponsorship provided by the EPSRC through the ENCYCLOPAEDIC program grant.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Citation
CHONG, W.W.F., TEODORESCU, M. and RAHNEJAT, H., 2011. Physio-chemical hydrodynamic mechanism underlying the formation of thin adsorbed boundary films. Faraday Discussions, 156 pp.123-136.Publisher
© Royal Society of ChemistryVersion
- NA (Not Applicable or Unknown)
Publication date
2012Notes
This article is closed access.ISSN
1359-6640Publisher version
Language
- en