Effect of liquid crystal molecular orientation controlled by an electric field on friction

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.