Collaborative Research: Hierarchically Structured Polycrystalline Hollow Gold Nanoparticles- A Model System for Integrated Experimental and Multiscale Computational Nanomechanics

合作提案：层次结构的多晶空心金纳米粒子-一个模型系统集成的实验和多尺度计算纳米力学Abstract德克萨斯大学阿灵顿分校（UTA）和明尼苏达大学（UMN）之间的合作赠款基金相结合的实验和理论/计算研究计划，旨在获得基本的理解层次结构的金纳米球的力学。在单个结构中存在多个长度尺度，例如晶粒尺寸、壳厚度和球体直径。具体而言，我们的金纳米球直径约为100 nm，具有厚度为20至50 nm的多晶壳，晶粒尺寸约为5 nm。这样的组合提供了一个？金色的？有机会探索结构层次对纳米材料变形机制的影响。由于其中空的性质，金纳米球可以很容易地观察和测试与原位TEM纳米压痕没有精心的样品制备。 它们可以被精确地定位到一个可寻址的阵列使用？静电漏斗法这大大方便了纳米压痕实验，使统计检查。具有相似特性的模型多晶空心纳米粒子将模拟与国家的最先进的多尺度理论/计算技术，结合联合收割机分子动力学和离散元方法。从原位TEM纳米压痕实验输入将大大促进多尺度建模，特别是时间加速和粗粒化的关键问题。所得模拟结果将有助于理解实验数据，并以原子级分辨率识别变形机制。纳米级金属的一般力学行为对于诸如新的超强结构材料、微电子和微-和纳米机电设备和系统的技术应用具有极大的兴趣。如果成功，这项研究将有助于建立针对此类应用的重要设计原则。将分子动力学与离散元方法相结合来解决不同长度尺度的问题，有望在建模界得到广泛的应用。 拟议的研究计划与多层次的教育和推广计划相结合，包括开发旨在教育学生跨学科领域的新课程，为K-12学生举办夏令营，并通过MRSEC-UMN，现有REU，网络模块开发和在高中和明尼苏达州科学博物馆进行演示的推广活动。与西班牙裔专业工程师协会合作的协调外展计划提出了通过针对和参与德克萨斯州的大量西班牙裔人口，为代表性不足的群体提供机会，其中包括少数民族招聘计划，为K-12西班牙裔学生举办的SciTech拉丁裔夏令营，以及公众意识部分。

Collaborative Proposal: Hierarchically Structured Polycrystalline Hollow Gold Nanoparticles- A Model System for Integrated Experimental and Multiscale Computational NanomechanicsAbstractThis collaborative grant between the University of Texas at Arlington (UTA) and University of Minnesota (UMN) funds a combined experimental and theoretical/computational research program that aims to gain fundamental understanding into the mechanics of hierarchically structured gold nanospheres. Multiple length scales such as grain size, shell thickness, and diameter of sphere exist within an individual structure. Specifically, our gold nanospheres are about 100 nm in diameter, and feature a polycrystalline shell with a thickness ranging from 20 to 50 nm, and grain size around 5 nm. Such combination provides a ?golden? opportunity to explore the effects of structural hierarchy on the deformation mechanisms of nanoscale materials. Due to their hollow nature, the gold nanospheres can be easily observed and tested with in-situ TEM nanoindentation without elaborate sample preparation. They can be positioned precisely into an addressable array using the ?electrostatic funneling method?. This greatly facilitates nanoindentation experiments, enabling a statistical examination. Model polycrystalline hollow nanoparticles with similar characteristics will be simulated with state-of-the-art multiscale theoretical/computational techniques that combine Molecular Dynamics and Discrete Element Method. Experimental input from the in-situ TEM nanoindentation will greatly facilitate the multiscale modeling, specifically the critical issues of time-acceleration and coarse-graining. The obtained simulation results will help comprehend experimental data and identify deformation mechanisms with atomistic resolution. The general mechanical behavior of nanoscale metals is of great interest for technological applications such as new ultrastrong structural materials, microelectronics and micro- and nano-electromechanical devices and systems. If successful, this research will help establish important design principles targeting such applications. The proposed combination of Molecular Dynamics with Distinct Element Method to tackle problems at different length scales is expected to find broad applications in the modeling community. The proposed research program is integrated with a multi-layered education and outreach program that includes development of new courses designed to educate students in an interdisciplinary field, summer camps for K-12 students, and outreach activities through MRSEC-UMN, existing REU, cyber module development, and demonstrations at high schools and the Science Museum of Minnesota. A coordinated outreach plan in partnership with the Society for Hispanic Professional Engineers is proposed to provide opportunities to underrepresented groups by targeting and involving the large Hispanic population in the State of Texas, which includes a minority recruitment program, a SciTech Latino Summer Camp for K-12 Hispanic students, and a public awareness component.