Characterization of ionic liquid films in view of tribological properties and development of structure-property relationships by means of electrochemical surface force apparatus

该研究项目的目标是表征和检查离子液体薄膜的不同层上的摩擦学行为。摩擦学，或者说是对相互接触滑动的表面的研究，在我们的日常生活中具有实际意义，并且具有极其重要的经济意义。测量到的两个物体之间的摩擦力是原子尺度上表面累积相互作用的结果。特别是，界面的物理和化学性质决定了摩擦行为.由于离子液体的独特性质，包括在固体表面前形成层状结构，它们是未来高性能润滑剂的理想候选者。在本研究项目中，纳米和微米尺度的实验将在英国牛津大学使用表面力装置进行，该装置对样品进行完全电化学控制。电化学方法的集成的优点是可以可逆地和原位地改变关键参数，例如基底的粗糙度以及离子液体层的稳定性和布置。这个项目的主要目标是了解构成的固体-液体界面的滑动平面内的第一个几纳米远离表面。机械性能将被探测与所需的开发分子长度尺度上的结构-性能关系的高力分辨率。牛津大学和申请人已经对离子液体的摩擦性能进行了初步研究。基于这些结果，离子液体的特定性质，包括阴离子和阳离子的大小、电荷数和烷基链的长度以及基底的特性，例如表面粗糙度将变化;此外，计划用水和盐控制离子液体的污染，以检查它们对摩擦性能的影响。本研究计划中描述的基础研究对于建立离子液体的摩擦学应用至关重要。

The goal of this research project is to characterize and examine the tribological behaviour on different layers of thin films of ionic liquids. Tribology, or the study of surfaces in contact sliding against each other is of practical relevance in our everyday life and of utmost economical importance. The measured friction force between two bodies is a result of cumulative interactions of the surfaces on the atomic scale. In particular, the physical andchemical properties of the interface determine the frictional behavior. Due to the unique properties of ionic liquids, including the formation of a layered structure in front of solid surfaces, they are ideal candidates for tomorrows high-performance lubricants. Within this research project experiments at the nano- and micrometer scale will be performed at the University of Oxford in the United Kingdom using a surface force apparatus operating with full electrochemical control of the sample. The advantage of the integration of electrochemical methods is the possibility to alter key parameters such as the roughness of the substrate as well as the stability and arrangement of the ionic liquid layers reversibly and in situ. The primary objective of this project is to understand the constitution of the solid-liquid interface as the sliding plane within the first few nanometers apart from the surface. The mechanical properties will be probed with a high force resolution as required to develop structure-property relationships on the molecular length-scale. Preliminary studies into the frictional properties of ionic liquids have already been carried out at Oxford and by the applicant. Based on these results specific properties of the ionic liquids, including the size of the anions and cations, the charge number and the length of the alkyl chain as well as characteristics of the substrate, e.g. the surface roughness will be varied; furthermore, the controlled contamination of the ionic liquids with water and salts is planned to examine their effect on the friction properties. The fundamental research described in this research proposal is crucial for the establishment of tribological applications of ionic liquids.