Total internal reflection Raman spectroscopy of poly(alpha-olefin) oils in a lubricated contact

Praveena, Manimunda and Guha, Kaustav and Ravishankar, Abhilash and Biswas, Sanjay K and Bain, Colin D and Jayaram, Vikram (2014) Total internal reflection Raman spectroscopy of poly(alpha-olefin) oils in a lubricated contact. In: RSC ADVANCES, 4 (42). pp. 22205-22213.

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Abstract

The rheology of a poly(alpha-olefin) base oil (PAO) in a sliding point contact has been investigated by total internal reflection (TIR) Raman spectroscopy. TIR Raman has the sensitivity to analyse nanometer-thick lubricant films in a tribological contact. The Raman signal generated from the sliding contact was used to determine the lubricant film thickness. The experimentally obtained film thicknesses were compared with theoretical calculations and a transition from Newtonian to non-Newtonian behaviour was observed at high shear rates. The Raman spectra showed no significant changes in the conformation of the PAO chains under the applied conditions of pressure and shear, but the polarisation dependence of the spectra revealed a preferred orientation of the hydrocarbon side chains in the shear-thinned region. Monolayers formed by a boundary lubricant, arachidic acid, dissolved in the PAO could be detected on the surfaces in the elastohydrodynamic regime.

Item Type:	Journal Article
Publication:	RSC ADVANCES
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	Copyright for this article belongs to the ROYAL SOC CHEMISTRY
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	22 Jul 2014 11:44
Last Modified:	22 Jul 2014 11:44
URI:	http://eprints.iisc.ac.in/id/eprint/49477

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