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

据估计，由于粘附、摩擦和磨损机制造成的能量损失，美国每年损失1000亿美元。该奖项支持的研究目标是对天然和有机硅烷功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、粘附和磨损有一个清晰的认识。材料的磨损，如二氧化硅和氧化铝将研究使用原子力显微镜（AFM）。这些研究将使我们能够在原子尺度上直接跟踪缺陷成核，并开发磨损的预测模型。此外，由于滑动接触中真实表面之间的摩擦和粘附是由纳米级表面凹凸不平（约10 - 50 nm）的相互作用决定的，因此将开发基于可控尺寸的二氧化硅纳米颗粒的测量平台。AFM尖端与这些明确定义的表面凹凸不平的相互作用将很容易模拟真实凹凸不平接触的条件，从而确定在不同环境条件下，凹凸不平大小对有机硅烷基润滑剂功效的影响。如果成功，这项工作将指导新型分子基润滑剂的工程设计，并提高微器件的设计能力。参与该项目的学生将获得对美国技术竞争力持续发展至关重要的领域的广泛教育和培训，包括材料科学、工程和表面化学。这项工作将由私家科学主任和学生在非正式的公众科学讲座、会议和部门研讨会上作报告，广泛传播。培训将通过与国家实验室（如NIST）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被纳入小学学生的示范和研究生水平的化学、材料科学和工程学生的仪器方法训练营。

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.