Triborheology and molecular structure of novel ionic liquids influenced by flow and electric fields (IL-Triborheology)

• Applicants: Professor Dr. Christian Friedrich; Dr. Andreas Kailer
• Subject Area: Polymer Materials
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 187169894

In our project we propose a fundamental study of novel ionic liquids (ILs) that may be applicable in tribological systems due to their specific rheological and tribological properties. The main goal is to establish relationships between rheological and tribological properties of ILs and to understand how these properties are linked to the molecular structure of IL. Novel ILs with organic, azolatebased anions will be studied. New ILs possess unique molecular structures and high thermal stability, which is desirable for lubrication. Moreover, azolate anions are less corrosive than fluoridebased ones. To expand the study, novel IL systems will be explored based on eutectic mixtures of various Azolium Azolates ILs with even further depressed melting and glass transition temperatures. We develop and utilize new tribological and rheological techniques towards a thorough triborheological characterization of IL. Rheological studies will be performed with crossover to gapdependent rheology (small gap-size). This will allow us to link rheological properties under high shear in the bulk of IL with the friction dynamics and interactions of IL–surface pairs. Results will be compared with direct tribological data. By comparing the rheological and the tribological properties (with and without electric fields), we will establish important correlations between molecular structures, rheological effects at high shear rates and friction and wear behaviour. It might even be possible to control friction and wear by electric fields and therefore minimize energy consumption and significantly enhance the reliability and lifetime of tribological systems that work under extreme conditions. Further investigations of the corrosivity and the surface effects will lead to the development of friction and wear mechanisms and of the corresponding model of IL lubricated tribological systems. Since there has not yet been any fundamental research in this field and the technological impact of this study is promising, there is an urgent need for the proposed work on electrically influenced triborheology of IL.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1191: Ionic Liquids