Effect of liquid crystal molecular orientation controlled by an electric field on friction. (November 2017)

• Record Type: Journal Article
• Authors: Gao, Yuan; Xue, Boce; Ma, Liran; Luo, Jianbin
• Is Part Of: Tribology international. Volume 115(2017)
• Page Start: 477
• Page End: 482
• Publication Date: 2017-11
• Subjects: Thin-film lubrication -- Liquid crystal -- Orientation -- Electric field; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2017.06.021
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: Molecular orientation of the lubricating film will affect the lubrication state, especially in boundary lubrication. In this work, electrical field was used to affect the orientation of liquid crystal molecules during friction. We demonstrated that the use of an electric field applied between the steel ball and the chromium film on the surface of the glass plate provided an effective method for controlling the orientation of the liquid crystal molecules in a sliding point contact. The coupling effects of shear and electric field on friction were investigated with an in situ Raman spectrometer. This work shed new light on the influence of the adsorbed film on sliding friction coefficient, especially in thin-film lubrication regime. Graphical abstract: Highlights: The intensity of Raman spectra can be used to evaluate the orientation of the LC. The electric field induced a homeotropic orientation of the lubricating molecules. The friction coefficient changed with the orientation of the lubrication molecules. The fluidity of the liquid crystal was decreased by the electric field.