Experimental studies of electrorheological properties of lubricating oils containing ionic liquid. Part 3. Microscopic examination of the ER effect mechanism

The article presents the results of in situ microscopic observations of quasihomogenic mixtures of hydrocarbon oils containing ionic liquids. Observations were made using NIKON ECLIPSE LV 100 D optical microscope. The mechanism of generating the ER effect in two mixtures was observed, i.e., in silicone damping liquid GP-1, which is polimethylsiloksane mixture containing 2% (v/v) of ionic liquid CJ 001, i.e., tetrafluoroboran 1-methyl-3-octyloxymethylimidazolium and base polialfaolefine oil PAO-6 which containing 2% (v/v) of ionic liquid CJ 008, i.e., trihexyltertradecylfosfonium bis(trifluoromethylsulfonyl) imide as well as in the two-component standard liquid LID3354s. The ob-servations carried out showed that the prepared mixtures had generated the ER effect. At the threshold value E = 0.3 kV·mm–1, the ER effect disappeared. Photographs, presented in the paper, show changes in the structure of mixtures containing ionic liquids that occur under the influence of an external elec-tric field, consisting in the formation of „fibril chains and/or fibril streams” and then, their destruction and accumulation of ionic liquid particles at the electrodes. Keywords: electrorheological effect (ER), lubricating oils, ionic liquids, microscopy