Collaborative Research: Atomistic Simulations of the Nanotribology of Carbon-based Materials: Establishing Links between Structure, Chemistry, and Performance

这项工作的研究目标是完成波动电荷分子动力学程序和势能函数的开发，该程序和势能函数能够可靠地捕获碳基材料和含氧环境物种(如水)之间发生的键断裂和形成事件。“碳基材料”一词涵盖了广泛的材料，包括生物的构件、碳的同素异形体和碳基薄膜。由于碳基固体润滑剂具有高硬度和超低摩擦磨损等理想性能，它们正被用于或考虑用于广泛的应用，包括空间系统、微型机电系统、整形外科植入物、计算机硬盘，以及作为构建基于DNA的微传感器的支架。也许阻止碳基材料更广泛地用作固体润滑剂的最重要因素是它们的摩擦力对环境的敏感性。这个项目还将验证一个基于类似形式的势能函数，该函数可以模拟含硅、含碳和含氢的系统的动力学。从这些开发项目中获得的知识可以用来创造一种势，能够模拟含硅、含氧和含氢体系中的带电化学反应。然后，这些工具可以用来检测碳基材料在水存在下的纳米摩擦学和机械性能，掺硅类金刚石的性能，以及硅-C上的外延石墨烯。如果成功，这项研究工作将提供几种新的工具，可以用来研究原子尺度的动力学。此外，还将对水等环境物种影响碳基固体润滑剂性能的方式有一个基本的了解。这些知识将允许合理设计具有所需摩擦学和机械性能的碳基固体润滑剂，并提高可使用碳基固体润滑膜的应用的可行性。作为该项目的一部分，通过将纳米摩擦学模块整合到现有的USNA STEM计划和俄亥俄大学的DAPCEP计划中，将向广泛的初中生和高中生介绍纳米摩擦学。还将为俄亥俄州立大学研究生级别的摩擦学课程开发纳米摩擦学模块。

The research objectives of this work are to complete development of a fluctuating-charge molecular dynamics code and potential energy function that are capable of reliably capturing bond breaking and forming events that occur between carbon-based materials and oxygen-containing environmental species, such as water. The phrase "carbon-based materials" encompasses a broad range of materials, including the building blocks of biology, allotropes of carbon, and carbon-based films. Because carbon-based solid lubricants have desirable properties, such as high hardness and ultralow friction and wear, they are being used or considered for a wide range of applications that include space systems, micro-electromechanical systems, orthopedic implants, computer hard disks, and as scaffolds on which to build DNA-based microsensors. Perhaps the most significant factor that has prevented even wider spread use of carbon-based materials as solid lubricants is the sensitivity of their friction to the environment. This project will also validate a potential energy function based on a similar formalism that can model dynamics in Si-, C- and H- containing systems. Knowledge gained from these development projects can be used to create a potential capable of modeing chemical reactions in Si-, O- and H- containing systems with charge. These tools can then be used to examine the nanotribology and mechanical properties of carbon-based material in the presence of water, the properties of Si-doped DLC, and epitaxial graphene on Si-C.If successful, this research effort will provide several new tools that can be used to examine dynamics at the atomic scale. In addition, a fundamental understanding of the way in which environmental species, such as water, impact carbon-based solid lubricant performance will be developed. This knowledge will allow for the rational design of carbon-based solid lubricants with the desired tribological and mechanical properties and increase the viability of applications where carbon-based solid lubricant films can be used. Also as part of this project, a broad range of middle and high school students will be introduced to nanotribology via the integration of a nanotribology module into the existing USNA STEM program and into the DAPCEP program at OU. Nanotribology modules will also be developed for graduate-level tribology classes at OU.