On-demand Generation of Diamond-like-carbon Layers for Efficient Lubrication of Mechanical Systems

交通运输占美国石油消费的70%。改善运输和其他机械系统中的润滑可以提高效率，减少维护和与石油消耗相关的成本。同样重要的是，汽车发动机等机械系统在启动和停止过程中容易磨损。这对于混合动力车辆尤其重要，混合动力车辆的发动机在动力传动系统每次切换到电池作为动力源和切换到电池作为动力源时启动和停止，并且对于许多新的传统乘汽车而言，这些乘用车正在实施这种“启停”技术，以通过在车辆在交通中空转或在红绿灯处自动关闭发动机来减少燃料消耗。需要为这些具有频繁启停循环的现代发动机系统设计新的润滑剂。该研究小组探索将新的润滑剂添加剂引入常规发动机油中，当受到启停循环中经历的条件时，这些润滑剂很容易分解成润滑和保护性的类金刚石碳层。因此，这些层在需要的时候和地方提供摩擦减少和磨损保护。这种多学科研究涉及表面化学，材料科学和机械工程;它不仅在学科领域，而且在通信，创业，国际和多元文化接触，并积极参与专业活动提供基础广泛的研究生培训。本研究的目的是探索和开发一种新的方法，在原位和按需沉积润滑类金刚石碳膜的摩擦组件表面。该方法使用表面活性分子（溶解在基础油中），这些分子用应变亚稳碳环官能化。这些分子的表面活性基团使它们能够容易地吸收到摩擦部件表面上。在边界条件下，由于粗糙处的摩擦加热产生的热能导致这些分子的亚稳碳环分解，从而形成润滑的类金刚石碳层，从而提供原位和按需的摩擦减少和磨损保护。研究小组计划从两个方面系统地修改这些添加剂分子的化学结构：表面活性基团的化学性质和表面活性基团与应变亚稳碳环之间的-CH 2间隔基的数量。研究调查将探索这些添加剂分子的化学结构，分解动力学，以及在不同的边界润滑条件下的摩擦学性能之间的关系。

Transportation accounts for 70 percent of the oil consumption in the US. Improving lubrication in transportation and other mechanical systems results in better efficiency, reduced maintenance and cost associated with oil consumption. Just as critical, mechanical systems such as automotive engines are prone to wear during starts and stops. This is particularly important for hybrid vehicles, whose engines start and stop each time the drivetrain switches from and to the battery as the power source, and for many new conventional passenger cars that are implementing such "start-stop" technology to reduce fuel consumption by automatically shutting the engine off when the vehicle is idling in traffic or at stoplights. There is a need for new lubricants designed for these modern engine systems with frequent start-stop cycles. The research team explores the introduction of new lubricant additives into regular engine oils that readily decompose into lubricious and protective diamond-like-carbon layers when subjected to conditions experienced in start-stop cycles. These layers therefore provide friction reduction and wear protection when and where they are needed. This multidisciplinary research involves surface chemistry, materials science, and mechanical engineering; it provides broad-based graduate training not only in subject areas, but also in communications, entrepreneurship, international and multi-cultural exposure, and active participation in professional activities. The objective of this research is to explore and develop a novel approach to in situ and on-demand deposition of lubricious diamond-like-carbon films onto tribo-component surfaces. The approach uses surface-active molecules (dissolved in base oil) that are functionalized with strained metastable carbon rings. The surface-active group of these molecules allows them to readily absorb onto tribo-component surfaces. Under boundary conditions, thermal energy due to frictional heating at asperities causes the metastable carbon rings of these molecules to decompose, resulting in the formation of a lubricious diamond-like-carbon layer, thus providing in situ and on-demand friction reduction and wear protection. The research team plans to systematically modify the chemical structure of these additive molecules in two aspects: the chemical nature of the surface-active group and the number of -CH2 spacers between the surface-active group and the strained metastable carbon ring. Research investigations will explore the relationship among the chemical structure of these additive molecules, decomposition kinetics, and the tribological performance under different boundary lubrication conditions.