Mechanical Properties of Freestanding Nanoparticle Sheets

技术摘要：该项目研究了一类由金属纳米颗粒自组装而成的新型金属薄片，每个颗粒都被一个由短有机分子组成的薄壳包围，这些分子充当颗粒间的间隔物。作为紧密堆积的单层，这些片是可以由纳米颗粒构建块制造的最薄的结构。 该片材具有显著的机械强度和鲁棒性，包括几个千兆帕斯卡的杨氏模量，并且可以覆盖在数百至数千个颗粒宽的开口上。 由此产生的独立式膜提供了特殊的机会，调查纳米力学性能，使之有可能调查大型组装的纳米级积木没有干扰的基板，而在同一时间允许直接实验访问，通过一系列的探针，如电子或扫描探针显微镜，到个别积木本身。该项目将系统实验与弹性响应的模拟相结合，解决了与原子作为构建块的系统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。要追求的其他方向包括评估使用片材作为MHz范围内的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。 一系列推广活动包括与一个主要的科学博物馆一起开发和制作实践活动的原型。非技术性总结：纳米粒子自组装为下一代材料的设计提供了特殊的机会。该项目研究了一种新的由金属纳米颗粒组装而成的金属薄片。 作为一个粒子薄层，这些片是可以用纳米粒子制造的最薄的结构。 一个特殊的特点是，他们结合了联合收割机极高的灵活性与不寻常的机械强度。 这种结合使得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结合起来提供了一个自然平台。它将培养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推广活动，包括与附近的一个主要科学博物馆一起开发和原型化实践活动。

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.