Influence of thin-fluid-film effects on surface characterization with dynamic atomic force microscopy

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。该奖项的研究目标是加深对探针样品薄膜流体作用力对在环境空气中获取的动态原子力显微镜(AFM)图像准确性的影响的基本了解。特别是，这项工作将量化环境、成像参数和化学成分变量对成像伪影出现的影响，例如多稳定性，从而在轻拍模式AFM中，对于相同的样本、探头和成像参数集，可以获得多达无限数量的图像。该项目依赖于成像和光谱AFM实验，这些实验将在受控环境条件下进行，使用标准和定制的探头，扫描隧道显微镜和透射电子显微镜实验，以及原子、连续和非线性动力学AFM模拟。成果包括控制薄膜-流体-探头-样本力的参数与获取的地形图像的准确性之间的定量关系目录、多尺度建模和分析工具、通过硬件进行的演示和验证、研究结果的记录和工程学生教育。如果成功，这项研究的结果将有助于正确解释在高冲击性技术中常用的各种纳米结构上进行的AFM实验，如MEMS/NEMS、生物技术、微型机器人外科手术、药物设计、组织工程等，在这些领域，准确的地形测量至关重要，并可能影响人类的福祉。此外，将理论和实验纳米科学应用于具体的研究问题将有助于教育下一代劳动力。这将在短期内通过丰富现有的多尺度模拟课程、通过为参加马里兰大学(UMD)预科课程的高中高年级学生进行研究性实习以及通过为参加UMD Invens领导力学院的本科生进行短期研究项目来实现。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The research objective of this award is to develop fundamental understanding of the effect of probe-sample thin-fluid-film forces on the accuracy of dynamic atomic force microscopy (AFM) images acquired in ambient air. In particular, the work will quantify the impact of environmental, imaging parameter and chemical composition variables on the emergence of imaging artifacts, such as multistability, whereby up to an infinite number of images can be obtained for the same sample, probe and set of imaging parameters in tapping-mode AFM. The project relies on imaging and spectroscopy AFM experiments to be conducted under controlled environmental conditions with standard and customized probes, scanning tunneling microscopy and transmission electron microscopy experiments, and atomistic, continuum and nonlinear dynamics AFM simulations. Deliverables include a catalog of quantitative relationships between the parameters governing thin-fluid-film probe-sample forces and the accuracy of the acquired topographical images, multi-scale modeling and analysis tools, demonstration and validation via hardware, documentation of research results and engineering student education.If successful, the results of this research will aid in the correct interpretation of AFM experiments performed on a variety of nanostructures commonly used in high-impact technologies such as MEMS/NEMS, biotechnology, microrobotic surgery, drug design, tissue engineering, etc., where accurate topographical measurements are critical and could impact the well-being of human beings. Additionally, the application of theoretical and experimental nanoscale science to specific research problems will contribute to the education of the next-generation workforce. This will take place in the short term through enrichment of an existing multi-scale simulation course, through research internships for high-school seniors participating in the University of Maryland (UMD) Pre-College Program and through short research projects for undergraduate students enrolled in the UMD Inventis Academy of Leadership.