Mechanical Properties of Freestanding Nanoparticle Sheets

技术摘要：该项目研究了一种由金属纳米颗粒自组装而成的新型超薄片，每个颗粒被一层短有机分子的薄壳包围，这些分子充当颗粒间的间隔物。作为紧密堆积的单分子层，这些薄片是可以由纳米颗粒构建块制造的最薄的结构。这种薄片表现出非凡的机械强度和坚固性，包括几十亿卡的杨氏模数，可以覆盖数百到数千个颗粒宽的开口。由此产生的独立膜为研究纳米机械性能提供了特殊的机会，使得在不受衬底干扰的情况下研究纳米级构建块的大型组件成为可能，同时允许通过一系列探针(如电子或扫描探针显微镜)直接实验访问单独的构建块本身。该项目将系统实验与弹性响应模拟相结合，解决了对以原子为构件的系统也具有根本相关性的问题，例如粒子排列中的缺陷如何影响整体机械响应。其他有待研究的方向包括评估将纳米片材用作机械谐振器和传感器的可行性，以及将纳米颗粒片材折叠成三维结构的可能性。该项目将培训一名博士后和一名研究生掌握重要的纳米科学知识。一系列外展活动包括与一家大型科学博物馆进行动手活动的开发和原型制作。非技术摘要：纳米颗粒自组装为下一代材料的设计提供了特殊的机会。该项目研究一种由金属纳米颗粒组装而成的新型超薄板。作为单粒子薄层，这些薄片是可以用纳米颗粒制造的最薄的结构。一个特别的特点是，它们结合了极高的灵活性和非凡的机械强度。这种结合使设计新型涂层以及新型自组装纳米机械谐振器和传感器成为可能。该项目为将研究与教育和外联相结合提供了一个天然的平台。它将培训一名博士后和一名研究生掌握重要的纳米科学知识，并向本科生介绍前沿科学。一个特殊的组成部分是一系列的外联活动，其中包括与附近的一家大型科学博物馆一起开发实践活动并制作其原型。

TECHNICAL SUMMARY:The project investigates a new class of ultrathin sheets that are self-assembled from metal nanoparticles, each particle being surrounded by a thin shell of short organic molecules that act as inter-particle spacers. As close-packed monolayers these sheets are the thinnest structures that can be fabricated from nanoparticle building blocks. The sheets exhibit remarkable mechanical strength and robustness, including Young's moduli of several GigaPascal, and can be draped over openings hundreds to thousands of particles wide. The resulting freestanding membranes provide special opportunities for investigating nanomechanical properties, making it possible to investigate large assemblies of nanoscale building blocks without interference from a substrate, while at the same time allowing for direct experimental access, via a range of probes such as electron or scanning probe microscopies, to the individual building blocks themselves. Combining systematic experiments with simulations of the elastic response, the project addresses questions that are of fundamental relevance also for systems with atoms as building blocks, such as how the overall mechanical response is affected by defects in the particle arrangement. Additional directions to be pursued include assessing the feasibility of using the sheets as mechanical resonators and sensors in the MHz range, and the possibility of folding the nanoparticle sheets into three-dimensional structures. The project will train one postdoc and one graduate student in vital nanoscience know-how. A set of outreach activities includes the development and prototyping of hands-on activities with a major science museum.NON-TECHNICAL SUMMARY:Nanoparticle self-assembly offers special opportunities for the design of next-generation materials. This project investigates a new class of ultrathin sheets, assembled from metal nanoparticles. As one-particle-thin layers, these sheets are the thinnest structures that can be fabricated with nanoparticles. A special feature is that they combine extreme flexibility with unusual mechanical strength. This combination makes it possible to design novel coatings as well as new types of self-assembled, nanomechanical resonators and sensors. The project provides a natural platform for integrating research with education and outreach. It will train one postdoc and one graduate student in vital nanoscience know-how, and introduce undergraduates to forefront science. A special component is a set of outreach activities that include the development and prototyping of hands-on activities with a nearby major science museum.