GOALI: Visualizing and Measuring Nanoscale Properties through Multi-spectral Atomic Force Microscopy for the Design and Discovery of Novel Materials

科学发现的巨大进步和人类的进步常常伴随着新的科学工具的发展，这些工具使我们能够“看到”远远超出我们日常经验的东西。原子力显微镜（AFM）就是这样一种工具，它能够以原子的分辨率在不同条件下可视化各种材料，从而彻底改变了材料科学。在过去，AFM被用来在一个频率上呈现对比度，但是现在可以在许多不同的频率上观察图像的多光谱对比度：实际上就像光学显微镜能够通过不同的滤光片观察对比度一样。该研究项目将允许普渡大学的研究人员与工业合作伙伴牛津仪器-庇护公司密切合作。该团队将创新方法，将这种多光谱对比转化为定量物理特性，以帮助设计和发现用于生物医学、能源存储和消费产品的下一代材料。通过普渡大学、多频AFM市场的领导者牛津仪器- asylum和瑞典KTH之间的合作，计划进行全面的理论和实验研究和推广计划，以显著推进多频AFM的最新技术。该项目还包括为学生开发聚合物相互作用和多频AFM的新课程，并增强动态AFM虚拟环境功能，用于聚合物的多频AFM操作，这将极大地造福学生和其他研究人员。当今最重要的多频原子力显微镜模式可以从概念上理解为具有慢速和快速时间尺度动力学的非线性系统。本项目将采用分析摄动、延续和实验方法来分析这些问题，从而在微悬臂运动、稳定性、分岔和混沌方面获得丰富的预测性见解。一方面，这些信息将有助于在稳定的条件下操作多频AFM，而另一方面，这些见解将有助于指导最适合在特定材料上产生对比度的操作条件。此外，复杂的计算工具和实验验证将允许在多频原子力显微镜中的实验观察物与电子、生物医学设备和消费产品中使用的软聚合物材料的局部特性之间实现前所未有的相关性。这些工具将通过nano-HUB网络基础设施上的动态原子力显微镜虚拟环境软件套件提供给全球数百名研究人员。这项工作是对多频原子力显微镜动力学基础的全面研究，是原子力显微镜向真正功能性、定量纳米级成像技术发展的下一个新兴前沿。研究结果将通过与牛津仪器（庇护）的密切合作转移到工业。虽然该项目的重点是多频原子力显微镜，但在许多成像技术中，多频方法是一个明显的趋势；例如，对比增强超声、电阻抗断层扫描和微波成像等。因此，在这项工作中开发的方法不仅可以扩展到其他生物医学或材料仪器中的多频成像方法，而且还可以为微纳米机电系统中的多光谱监测创造机会。

Great advances in scientific discovery and human progress have often followed the development of new scientific tools that allow us to "see" well beyond our everyday experience. The Atomic Force Microscope (AFM) is one such tool that has revolutionized materials science by its ability to visualize a wide variety of materials under different conditions with the resolution of an atom. In the past, AFM has been used to render contrast at one frequency but these days it is possible to observe multi-spectral contrast in images at many different frequencies: in effect like an optical microscope being able to observe contrast through different filters. This research project will allow Purdue University researchers to work closely with an industrial partner, Oxford Instruments-Asylum. The team will innovate methods to convert this multi-spectral contrast to quantitative physical properties to help in the design and discovery of next-generation materials for biomedical, energy storage, and consumer products. A comprehensive theoretical and experimental research and outreach program is planned to significantly advance the state-of-the art of multi-frequency AFM through a collaboration between Purdue University, Oxford Instruments-Asylum, a leader in the multi-frequency AFM market, and KTH, Sweden. The project also involves development of new courses in polymer interactions and multi-frequency AFM for students and enhancement of Virtual Environment for Dynamic AFM capability for multi-frequency AFM operation for polymers which will greatly benefit students and other researchers. The most important multi-frequency Atomic Force Microscopy modes today can be conceptually understood as nonlinear systems with slow and fast timescale dynamics. This project will undertake analytical perturbative, continuation, and experimental approaches to analyze these problems to yield a rich harvest of predictive insight into microcantilever motions, stability, bifurcations, and chaos. On one hand, this information will help operate multi-frequency AFM's in stable regimes, while on the other hand, the insight will help guide the operating conditions most appropriate to generate contrast on a specific material. Additionally, sophisticated computational tools and experimental validation will allow an unprecedented correlation between experimental observables in multi-frequency Atomic Force Microscopy and the local properties of soft polymeric materials used in electronics, biomedical devices, and consumer products. These tools will be made available to hundreds of researchers worldwide through the software suite Virtual Environment for Dynamic Atomic Force Microscopy on the cyber-infrastructure of nano-HUB. The work is a comprehensive study of the dynamical foundations of multi-frequency AFM, a next emerging frontier in the evolution of Atomic Force Microscope towards a truly functional, quantitative nanoscale imaging technology. The findings will be transferred to industry through the close collaboration with Oxford Instruments (Asylum). While the focus of the project is on multifrequency Atomic Force Microscopy, there is a clear trend towards multiple frequency methods across many imaging technologies; for example, in contrast enhanced ultrasound, electrical impedance tomography, and microwave imaging to name a few. Thus the approaches developed in this work could not only spill over to multi-frequency imaging methods in other biomedical or materials instrumentation but could also create opportunities for multi-spectral monitoring in micro- and nano-electromechanical systems.