Ionic Liquids Interactions with Materials Surfaces Applications in Tribology and Nanotechnology

Abstract

ABSTRACTThe extraordinary combination of high thermal stability, low volatility and the possibility of tailoring the physical and chemical properties of ionic liquids (ILs) by modifying their molecular features such as the length and nature of the cation lateral chains and the anion size and composition, has open the field of application of these green ordered fluids.ILs have shown their ability to provide effective lubrication with very low friction coefficients and wear rates under conditions for which the currently used lubricating fluids fail. These conditions cover strategic technologies such as aerospace, microelectronics and nanotechnology applications.At the present moment, there exist no liquid lubricants for high temperature, high vacuum and cryogenic conditions. We have determined the lubricating ability of ILs under extreme temperature conditions.We have determined the conditions for the formation of tribocorrosion reaction products at metal-metal and metal-polymer interfaces. In the case of fluorine or phosphorus-containing imidazolium ionic liquids, formation of metallic fluorides and phosphates at the contact surfaces is the determining wear mechanism step.The surface interactions of imidazolium room temperature ILs have been studied in a variety of materials in sliding contact under variable conditions, both as neat lubricants and as additives of conventional basestocks.The ability of ILs molecules to interact with surfaces has also been explored in nanotechnology applications. It is well known that the use of ILs as solvents in the synthetic route, allows the control of size and shape of a variety of nanoparticles. We have developed new polymer/IL/nanoparticle nanocomposites where the size, morphology and distribution of the nanoparticles are controlled by surface interactions with IL molecules.