MRI: Acquisition of a Dual-Beam Focused Ion Beam / Scanning Electron Microscope for Materials Research and Education

非技术描述这一主要研究仪器补助金允许在宾夕法尼亚大学辛格纳米技术中心购买先进的显微镜。这种显微镜使用两种不同类型的粒子-电子和离子-形成高放大率的图像，并给出有关材料化学成分的定量信息。显微镜配备了许多特殊工具，使其特别能够表征软物质：塑料，液晶聚合物和生物细胞等材料。这些材料在过去很难表征，因为它们在暴露于高能电子和离子时非常脆弱。该仪器能够将样品冷冻到非常低的温度，以缓解这一问题。它在本科生和研究生，访问科学家，博士后研究助理和当地高中学生和教师的教育中发挥着至关重要的作用，通过现有的NSF资助的中心在校园里的努力。该仪器也用于跨多个部门的高级本科生/研究生实验室课程。此外，它位于一个人员配备齐全，开放访问的NSF国家纳米技术协调基础设施设施中，允许来自附近多家公司和大学的科学家和工程师利用该工具进行自己的工作。技术说明聚焦离子束（FIB）/扫描电子显微镜（SEM）可以进行五项主要研究活动：（1）连续切片（冷冻）断层扫描，（2）用于后续扫描透射电子显微镜（S/TEM）表征的冷冻样品制备，（3）飞行时间二次离子质谱（ToF-SIMS）表征，（4）纳米纤维，和（5）S/TEM样品制备。连续切片可以深入了解液晶聚合物、胶体纳米颗粒超晶格、聚合物/纳米颗粒复合材料和其他分层材料的三维结构。冷冻转移和基于FIB的样品制备用于开发表征半结晶聚合物、胶体纳米颗粒超晶格和聚合物/纳米颗粒复合材料的方法。ToF-SIMS使研究人员能够以前所未有的分辨率了解聚合物材料中的扩散。该仪器支持辛格中心的Quattrone Nanofabstraction Facility的多个纳米制造工作，并为二维材料提供新的制造方法。最后，低电压/低电流的能力使辛格的S/TEM仪器在一系列需要精确的原子尺度表征的研究项目中使用的样品制备成为可能。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical DescriptionThis Major Research Instrumentation grant allows acquisition of an advanced microscope at the Singh Center for Nanotechnology at the University of Pennsylvania. This microscope uses two different types of particles - electrons and ions - to form high magnification images and give quantitative information about the chemical composition of materials. The microscope is outfitted with a number of special tools that make it particularly capable of characterizing soft matter: materials such as plastics, liquid crystal polymers and biological cells. These materials have been very difficult to characterize in the past as they are very fragile when exposed to high-energy electrons and ions. This instrument includes the ability to freeze samples to very low temperatures to mitigate this problem. It plays a vital role in the education of undergraduate and graduate students, visiting scientists, post-doctoral research associates and local high school students and teachers through existing NSF-funded Center efforts on the campus. The instrument is also used in advanced undergraduate/graduate laboratory classes across multiple departments. Additionally, its location in a fully staffed, open-access NSF National Nanotechnology Coordinated Infrastructure facility allows scientists and engineers from multiple nearby companies and universities to utilize the tool for their own work.Technical DescriptionThe focused ion beam (FIB) / scanning electron microscope (SEM) enables five major research activities: (1) serial sectioning (cryo)tomography, (2) cryo-sample preparation for subsequent scanning transmission electron microscopy (S/TEM) characterization, (3) time-of-flight secondary ion mass spectroscopy (ToF-SIMS) characterization, (4) nanofabrication, and (5) S/TEM sample preparation. Serial sectioning allows in-depth understanding of the three-dimensional structure of liquid crystal polymers, colloidal nanoparticle superlattices, polymer/nanoparticle composites and other hierarchical materials. Cryo-transfer and FIB-based sample preparation is used to develop methods for characterizing semi-crystalline polymers, colloidal nanoparticle superlattices and polymer/nanoparticle composites. ToF-SIMS allows researchers to understand diffusion in polymeric materials with unprecedented resolution. The instrument supports multiple nanofabrication efforts at the Singh Center's Quattrone Nanofabrication Facility and enables new fabrication approaches for two-dimensional materials. Finally, the low-voltage/low-current capabilities enables ultrathin sample preparation for use in the Singh's S/TEM instruments across a range of research projects which require exquisite atomic-scale characterization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.