Frictional response of fatty acids on steel

Sahoo, Rashmi R and Biswas, SK (2009) Frictional response of fatty acids on steel. In: Journal of Colloid and Interface Science, 333 (2). pp. 707-7148.

PDF fulltext.pdf - Published Version Restricted to Registered users only Download (855kB) | Request a copy

Abstract

Self-assembled monolayers of fatty acids were formed on stainless steel by room-temperature solution deposition. The acids are covalently bound to the Surface as carboxylate in a bidentate manner. To explore the effect Of Saturation in the carbon backbone on friction in sliding tribology, we Study the response of saturated stearic acid (SA) and unsaturated linoleic acid (LA) as self-assembled monolayers using lateral force microscopy and nanotribometry and when the molecules are dispersed in hexadecane, using pin-on-disc tribometry. Over a very wide range (10 MPa-2.5 GPa) of contact pressures it is consistently demonstrated that the unsaturated linoleic acid molecules yield friction which is significantly lower than that of the saturated stearic acid. it is argued, using density functional theory predictions and XPS of slid track, that when the molecular backbone of unsaturated fatty acids are tilted and pressed strongly by a probe, in tribological contact, the high charge density of the double bond region of the backbone allows coupling with the steel Substrate. The interaction yields a low friction carboxylate soap film on the substrate. The saturated fatty acid does not show this effect.

Item Type:	Journal Article
Publication:	Journal of Colloid and Interface Science
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Self-assembly;Anti-friction;Fatty acids;Lateral force microscopy;Nanotribology.
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	22 Jul 2009 09:47
Last Modified:	19 Sep 2010 05:30
URI:	http://eprints.iisc.ac.in/id/eprint/19976

Actions (login required)

View Item