Probing the Role of Surface Defects and Disorder on the Tribology of Nanoscopic Contacts

据估计，美国每年因粘着、摩擦和磨损机制造成的能量损失高达1000亿美元。该奖项支持的研究目的是清楚地了解天然和有机硅烷官能化氧化物表面的缺陷成核(例如，键断裂和分子堆积缺陷)如何影响界面的摩擦、粘合和磨损。使用原子力显微镜(AFM)研究二氧化硅和氧化铝等材料的磨损。这些研究将使我们能够直接跟踪原子尺度上的缺陷形核，并开发磨损预测模型。此外，由于滑动接触中真实表面之间的摩擦和粘合是由纳米级表面粗糙度(约10 50 nm)相互作用决定的，因此将开发一种基于尺寸可控的二氧化硅纳米颗粒的测量平台。AFM针尖与这些定义良好的表面粗糙面的相互作用将很容易模拟真正的粗糙面-粗糙面接触的条件，从而允许在不同的环境条件下确定粗糙度对有机硅烷润滑剂效果的影响。如果成功，这项工作将指导新分子润滑剂的工程设计，并提高微器件设计能力。参与该项目的学生将在对持续发展美国技术竞争力至关重要的领域获得广泛的教育和培训，包括材料科学、工程和表面化学。这项工作将通过非正式的公共科学讲座、会议和部门研讨会由国际学生和学生发表演讲来广泛传播。培训将通过与NIST等国家实验室的合作得到加强，为学生提供多样化的教育体验。这项工作的各个方面也将作为小学生的示范，并纳入为化学、材料科学和工程专业学生举办的研究生水平的仪器方法新兵训练营。

It has been estimated that $100 billion is lost annually in the US due to energy losses through mechanisms of adhesion, friction and wear. The objective of the research supported by this award is to generate a clear understanding of how defect nucleation (e.g. bond breaking and molecular packing defects) at native and organosilane functionalized oxide surfaces, influences friction, adhesion and wear of interfaces. Wear of materials such as silica and alumina will be studied using atomic force microscopy (AFM). These studies will enable us to directly follow defect nucleation on the atomic scale and develop predictive models for wear. Additionally, as friction and adhesion between real surfaces in sliding contact are dominated by the interactions of nanoscaled surface asperities (ca. 10 50 nm), a measurement platform based on silica nanoparticles of controlled size will be developed. The interactions of an AFM tip with these well defined surfaces asperities will readily mimic the conditions found at true asperity-asperity contacts, allowing for the influence of asperity size on the efficacy of organosilane based lubricants under varying environmental conditions to be determined. If successful, this work will guide the engineering of new molecular based lubricants and enhance microdevice design capabilities. Students participating in the project will gain broad education and training in areas critical for the continued development of US technological competitiveness, including materials science, engineering and surface chemistry. The work will be disseminated broadly through presentations by the PI and students via informal public science talks, conferences and departmental seminars. Training will be augmented by collaborations with national labs such as NIST, providing students with a diverse educational experience. Aspects of the work will also be incorporated as demonstrations for elementary school students and in a graduate level instrumental methods boot camp for chemistry, materials science and engineering students.