MRI: Acquisition of an In-Situ AFM/STM-TEM System for Interdisciplinary Nano-Research and Education at Michigan Tech

1.技术摘要本提案要求一种原位电力纳米探测系统，允许观察纳米级机制及其与纳米材料的定量机械和电气测量的直接相关性。原子力显微镜（AFM）和扫描隧道显微镜（STM）测量的纳米探测将通过新设计的侧入式AFM/STM-TEM样品保持器在透射电子显微镜（TEM）内进行。AFM和STM的结合将使研究机械和电刺激如何影响新材料的内部结构成为可能。如果没有新的仪器和技术，这些领域的许多基础科学活动就无法尝试。新的研究包括基础研究，以1）描述氮化硼和ZnO纳米材料中形变诱导的电性能的影响; 2）确定单个纤维素纳米晶体及其与生物聚合物基质的界面层的力学; 3）了解孔隙率和长度尺度对微致动器机械性能的影响。新系统有助于描述纳米粒子上的金属支持相互作用的影响？催化剂中的团聚，以及表面曲率尺寸对纳米颗粒变形的影响。此外，研究将包括开发描述纳米复合材料机械测试中的应力和应变场的分子模型，以及利用Si多孔传感器的MEMS微致动器的设计模型。计划针对K-12学生的广泛推广和教育计划，将包括传统上在科学领域代表性不足的学生。外展将使学生接触到纳米科学和工程方面的新科学发现。学生将首次观察到单个纤维素纳米晶体的变形;氮化硼纳米管中变形引起的压电行为;聚合物基质中纳米管的拔出测试;纳米颗粒的失效和粘附;以及真实的时间和空间中纳米多孔材料的变形。这些纳米机制的视频将在本科生和研究生课堂上展示，以刺激学生？研究兴趣和促进新兴技术的学习.所要求的仪器使材料科学家能够观察在外力和电压作用下材料内部结构的变化。这种最先进的仪器适合密歇根理工大学的样品保持器。现有的透射电子显微镜（TEM）。TEM的使用使科学家能够在纳米尺度上观察材料的内部结构（十亿分之一米或比人类头发细1,000倍）。这些纳米级材料将使用扫描隧道显微镜（STM）和原子力显微镜（AFM）进行检测和操作。在TEM中使用这两种技术的组合，科学家不仅可以“看到”材料内部的纳米级特征，而且还可以测量纳米级材料的电性能和强度。更好地了解电气和强度特性对于开发新的可持续材料至关重要。例如，这些技术将帮助科学家更好地了解氮化硼和氧化锌纳米材料的电性能变化，这是开发先进能量收集设备的核心。在另一个应用中，轻质和环境友好的生物聚合物复合材料的强度可以通过更好地设计聚合物基质和纤维素纳米材料之间的界面来提高。新系统将允许研究催化剂中的纳米颗粒团聚，孔隙率对微致动器强度的影响，以及纳米复合材料压痕过程中的应力和应变场。此外，该仪器将用于K-12学生的推广和教育计划，包括那些传统上在科学中代表性不足的学生。学生将接触到纳米科学和工程领域的最新科学发现。学生将接触到前沿的研究，并将能够观察纳米结构，学习如何更好地工程材料可以改善生活，使产品更环保，更好的社会。 此外，这些纳米机械的记录电影将用于激发本科生和研究生的研究兴趣，并促进新兴技术的学习。

1. Technical AbstractThis proposal requests for an in-situ electrical-force nanoprobing system that allows the observation of nanoscale mechanisms and their direct correlation with quantitative mechanical and electrical measurements of nanomaterials. The nanoprobing for atomic force microscopy (AFM) and scanning tunneling microscopy (STM) measurements will be performed inside a transmission electron microscope (TEM) through a newly designed side-entry AFM/STM-TEM specimen holder. The combination of AFM and STM will enable the investigation of how mechanical and electrical stimulation affects the internal structure of novel materials. Many fundamental scientific activities in these areas could not be attempted without the new instrumentation and technique. New research includes fundamental studies to 1) describe the effect of deformation induced electrical properties in boron nitride and ZnO nanomaterials; 2) determine the mechanics of individual cellulose nanocrystals and their interface layer with a biopolymer matrix; 3) understand the effect of porosities and length scales on the mechanical performance of microactuators. The new system aids in describing the effect of metal-support interactions on nanoparticles? agglomeration in catalysts, and the surface curvature size effect on nanoparticle deformation. In addition, research will include development of molecular models that describe the stress and strain fields in the mechanical testing of nanocomposites, and design models of MEMS microactuators that utilize Si porous sensors. Extensive outreach and educational programs targeted at K-12 students are planned and will include students traditionally underrepresented in the sciences. Outreach will expose students to new scientific discoveries in nano-science and engineering. Students will observe, for the first time, the deformation of individual cellulose nanocrystals; deformation induced piezoelectric behavior in boron nitride nanotubes; pull-out testing of nanotubes from a polymer matrix; failure and adhesion of nanoparticles; and deformation in nanoporous materials in real time and space. Videos of these nanomechanisms will be presented in undergraduate and graduate classrooms to stimulate students? research interests and promote learning of emerging technologies.2. Non-Technical AbstractThe requested instrument enables material scientists to observe changes in the internal structure of materials under the application of external forces and voltages. This state-of-the art instrument fits into the sample holder of Michigan Tech?s existing transmission electron microscope (TEM). Use of a TEM allows scientists to view the internal structure of materials at nanometer-length scales (one billionth of a meter or 1,000 times thinner than a human hair). These nanoscale materials will be detected and manipulated using a scanning tunneling microscope (STM) and an atomic force microscope (AFM). Using the combination of these two techniques inside a TEM, scientists can not only "see" nanoscale features inside the materials but, can also measure electrical properties and strength of nanoscale materials. Better understanding of electrical and strength properties is essential for developing new and sustainable materials. For instance, these techniques will help scientists to better understand the change in electrical properties of boron nitride and zinc oxide nanomaterials that are central in developing advanced energy harvesting devices. In another application, the strength of lightweight and environmentally-friendly biopolymer composites can be improved through better engineering of the interface between the polymer matrix and cellulose nanomaterials. The new system will allow study of nanoparticle agglomeration in catalysts, the effect of porosities on the strength of microactuators, and stress and strain fields during the indentation of nanocomposites. In addition, the instrument will be used for outreach and educational programs for K-12 students, including those traditionally underrepresented in the science. Students will be exposed to the newest scientific discoveries in the fields of nano-science and engineering. Students will be exposed to cutting-edge research and will be able to observe structures at the nanoscale, learning how better engineering of materials can improve lives, make products more environmentally friendly, and better society. Moreover, the recorded movies of these nanomechanisms will be used to stimulate the research interests in undergraduate and graduate students and promote learning of emerging technologies.