Identifying of thermotropic liquid crystal phase and its influence on lubricity of ionic liquids

In this article there is discussed a possibility of forming the liquid crystal structure in ionic liquids and its influence on performance characteristics, especially tribological, of these liquids. Formation of such thermal phase might influence on, among other things, easier creation of the boundary lubricating film, which is characterized by high viscous anisotropy. The results of tribological tests showed better lubricity of selected ionic liquids than modern PFPE oils. Identification of mesophase in ionic liquids was necessary. This method is described in the paper. Biolar PL polarizing interference microscope with thermal stabilizing table, with birefraction system, and Brüker Discover 8 powder diffraction instrument with a Cu lamp and monochromator were used. There was being searched the state characterized simultaneously by optical anisotropy properties and liquid state of aggregation. For identification of phase transition temperature, the additional calorimetric tests were carried out during the cycle of heating and cooling. These researches were carried out within the framework of the development and research project no. PBR 15-249/2007/WAT-OR0002904, financed by Ministry of Science and Higher Education during 2007-2011.