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

合作方案：分层结构的多晶空心金纳米粒子--集成实验和多尺度计算纳米力学的模型系统摘要这项由德克萨斯大学阿灵顿分校(UTA)和明尼苏达大学(UMN)共同资助的联合实验和理论/计算研究计划旨在获得对分层结构的金纳米球的力学的基本了解。在一个单独的结构中存在多个长度尺度，如颗粒大小、外壳厚度和球体直径。具体地说，我们的金纳米球的直径约为100 nm，具有厚度从20到50 nm的多晶壳，颗粒尺寸约为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通过原位电子显微镜纳米压痕来观察和测试，而不需要复杂的样品制备。它们可以使用静电漏斗方法精确地定位到可寻址的阵列中。这极大地方便了纳米压痕实验，使统计检验成为可能。具有相似特性的模型多晶中空纳米粒子将使用最先进的多尺度理论/计算技术进行模拟，该技术结合了分子动力学和离散元方法。来自原位纳米压痕的实验输入将极大地促进多尺度建模，特别是时间加速和粗粒化的关键问题。所获得的模拟结果将有助于理解实验数据，并以原子分辨率识别变形机制。纳米金属的一般力学行为在新型超强结构材料、微电子学以及微纳机电设备和系统等技术应用中具有重要意义。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。所提出的结合分子动力学和离散元方法来处理不同长度尺度的问题，有望在模型界得到广泛的应用。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在跨学科领域的新课程，为K-12学生举办夏令营，并通过MRSEC-UMN、现有的REU、网络模块开发以及在高中和明尼苏达州科学博物馆的演示开展推广活动。拟议与西班牙裔专业工程师协会合作制定一项协调的外联计划，通过以得克萨斯州大量拉美裔人口为目标并让其参与，为代表不足的群体提供机会，其中包括少数族裔招募计划、为K-12拉美裔学生举办的科技拉美裔夏令营和公共意识部分。

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.