Lubrication by Chemical Reaction Products at Sliding Interface

机器的滑动和摩擦界面，无论大小，都需要润滑来减轻摩擦和磨损，以确保可靠运行。否则，这些接口最终肯定会失败。滑动界面的最后一道防线是通过化学或物理方式粘附在固体表面上的边界润滑层。该层可以在机械装置的组装和完全操作之前施加到摩擦学界面，或者在装置的操作期间原位形成。这项工作的重点是在原位合成的边界润滑膜直接在滑动界面在设备的操作。这项研究可以产生一种新的润滑剂添加剂化学，可以减少汽车工业的寄生摩擦能量损失。这项工作还可以恢复微尺度机电技术，需要移动和滑动结构部件的可靠操作。该项目将培养学生的多学科技能，涵盖表面科学，分子表征和成像，以及摩擦学;这些学生将为新兴的纳米工程领域以及传统的润滑领域做出重大贡献。研究成果将被纳入研究生表面表征课程，并传播到广泛的科学和工程领域，涵盖化学，化学工程，机械工程，材料科学和摩擦学。机械化学反应容易发生在所有长度尺度;然而，控制反应产率和选择性的关键参数没有很好的记录或理解。这项研究的目的是推进机械化学反应，可以产生可靠的边界润滑膜的互补特性，如低界面剪切和高承载的机械理解。要研究的两个具体系统是（i）从气相中吸附的不饱和醇和酯的机械化学聚合，用于合成多元醇和多元醇酯的多层膜，以及（ii）润滑油中有机前体的二茂铁催化的机械化学反应及其在滑动界面处的石墨化。这项工作将进行系统的研究，以了解如何接触压力，剪切速率，反应物分子的结构，和基板材料的化学影响的机械化学反应产率和选择性，以及所产生的薄膜的润滑性能。这项研究的结果不仅将在极端条件下的润滑表面工程方面取得突破，而且还将推进摩擦化学的基础知识，这仍然是经验和定性的。

Sliding and rubbing interfaces of machineries, whether they are big or small, need lubrication to mitigate friction and wear for reliable operation. Otherwise, these interfaces are bound to fail eventually. The last defense of the sliding interface from such failure is boundary lubrication layers which are chemically or physically adhered to solid surfaces. This layer can be applied to the tribological interface before the assembly and full operation of mechanical devices, or formed in-situ during the operation of the devices. This work focuses on in-situ synthesis of boundary lubrication films directly at the sliding interfaces during the device operation. This research can generate a new lubricant additive chemistry which can reduce parasitic frictional energy losses for automobile industries. This work could also revive the microscale electromechanical technology requiring reliable operations of moving and sliding structural components. This project will train students with multidisciplinary skills covering surface science, molecular characterization and imaging, and tribology; these students will make substantial contributions to newly emerging nano-engineering fields as well as traditional lubrication sectors. The research outcome will be incorporated into a graduate surface characterization course and disseminated through to a broad range of science and engineering fields covering chemistry, chemical engineering, mechanical engineering, materials science, and tribology.Mechanochemical reactions readily occur at all length scales; however, key parameters governing the reaction yield and selectivity are not well documented or understood. This study aims at advancing mechanistic understanding of mechanochemical reactions that can produce reliable boundary lubrication films with complementary properties such as low interfacial shear and high load-bearing. Two specific systems to be studied are (i) mechanochemical polymerization of unsaturated alcohols and esters adsorbed from the vapor phase for synthesis of multilayer films of polyols and polyolesters and (ii) ferrocene-catalyzed mechanochemical reactions of organic precursors in lubricant oils and their graphitization at the sliding interface. This work will undertake systematic studies to understand how contact pressure, shear rate, structure of reactant molecules, and chemistry of substrate materials affect the mechanochemical reaction yield and selectivity as well as the lubrication properties of the produced films. The outcome of this study will not only make breakthroughs in surface engineering for extreme-condition lubrications, but also advance fundamental knowledge of tribochemistry which is still empirical and qualitative.