CAREER: Molecular-Based Engineering of Nanoparticle Self-Assembly

摘要-0448767职业计划的目标是建立一个严谨的科学基础，使纳米技术能够更好地控制纳米颗粒自组装。纳米颗粒具有孤立分子或块体材料所不具备的新颖性质，是纳米技术中最重要的成分之一，已被公认为下一代纳米器件和智能材料的理想基础。为了充分发挥其潜力，必须将纳米颗粒制备成多维有序阵列和预先设计的纳米结构。最近取得了重大进展。然而，目前的纳米颗粒制备方法仍然高度经验性，只产生了部分令人满意的结果。然而，现有的研究清楚地揭示了原子尺度特性在纳米颗粒自组装中的关键作用。这不仅指出了基础研究的价值，也为今后的研究指明了一个卓有成效的方向。这项拟议的研究将首先使用原子模型进行分子动力学模拟，该模型包含了重要的原子尺度特征，以专注于表面活性剂覆盖的纳米颗粒的早期自组装阶段。这些结果将提供对自组装初始阶段的微观洞察，并将被用作布朗动力学模拟的输入，以研究纳米粒子自组装中的更大范围的现象和问题，并被用于统计力学以尝试确定有利的自组装条件。在理论分析的基础上，提出了新的纳米构建单元(纳米链)和纳米加工策略(阶梯形表面和凹槽表面)。该项目将仔细评估它们的可行性和加工方案。智力优势：纳米粒子自组装方面的理论研究很重要，但仍然很少。由于微观细节的复杂性以及所涉及的时间和长度尺度，这不仅是对传统宏观理论的重大挑战，也是对分子模拟的重大挑战。该方案采用了多尺度、多现象的建模方法，结合了精细分子动力学模拟、大尺度布朗动力学模拟和新的统计力学框架的优点。原子尺度特性在纳米粒子自组装中的作用和相对重要性将被详细研究。纳米粒子系统的统计力学的新框架将得到证实。新的纳米制造想法将被仔细评估。因此，这项拟议的研究提出了一系列尚未尝试用于纳米粒子自组装研究的理论研究。更广泛的影响：拟议的研究将在以前从未实现的水平上提供对纳米粒子自组装的全面表征和理解。所产生的结果和见解将有助于改进目前的纳米制造途径，并为未来的纳米技术发展提供建议。该提案还包含一个强有力的教育部分，可持续有效地将国际和平研究所的研究专门知识融入几个级别的教育中。它通过实施名为“分子化学工程”的必修本科课程和名为“工程与科学中的分子模拟”的高级/研究生选修课，丰富了化学工程教育。分子模拟实验室也在开发中，以使分子模拟更接近学生。这些努力在化学和生物工程系和密苏里大学罗拉分校是全新的，并将开始建立一种新的文化，让学生从分子的角度来看待工程系统和问题。PI将继续吸引本科生从事基础研究，并鼓励他们继续深造。两名本科生研究人员将得到该项目的赞助，他们的部分工作是与高中生交谈，以促进他们对工程教育和基础研究的兴趣。这项教育计划将产生重大影响，因为分子模拟已经发展成为一种具有巨大学术和工业意义的实用工具，而且现代技术通过采用自下而上的方法使分子视角变得势在必行。

ABSTRACT - 0448767The goal of the CAREER proposal is to establish a rigorous scientific base that enables better control of nanoparticle self-assembly for nanotechnology. Possessing novel properties unavailable in either isolated molecules or bulk materials, nanometer-sized particles are one of the most important ingredients in nanotechnology and have been recognized as an ideal basis for next-generation nanodevices and smart materials. To fully realize their potential, nanoparticles must be fabricated into multidimensional ordered arrays and predesigned nanostructures. Significant progress has been made recently. However, current avenues of nanoparticle fabrication still remain highly empirical and produce only partially satisfactory results. Existing studies nevertheless revealed clearly the pivotal role of atomic-scale characteristics in nanoparticle self-assembly. This points out not only the value of fundamental research but also a fruitful direction for future studies. The proposed research will first perform molecular dynamics simulations with atomistic models that incorporate important atomic-scale characteristics to focus on early self-assembly stages of surfactant-capped nanoparticles. The results will provide microscopic insights into the initial phase of self-assembly and will be utilized as input to Brownian dynamics simulations to investigate larger-scale phenomena and issues in nanoparticle self-assembly, and to statistical mechanics for the attempt to identify favorable self assembly conditions. New nanobuilding unit (nanochain) and nanofabrication strategies (stepped and grooved surfaces) are also proposed based on theoretical analyses. Their feasibilities and processing protocols will be carefully assessed in this project.Intellectual merit: Theoretical study in the respect of nanoparticle self-assembly is important but still scarce. Because of the complexity in microscopic detail and in the time and length scales involved, it is a major challenge not only to conventional macroscopic theories but also to molecular simulation. This proposal employs a multi-scale, multi-phenomena modeling approach that combines the advantages of finer-scale molecular dynamics simulation, larger-scale Brownian dynamics simulation, and a new framework of statistical mechanics. The roles and relative importance of atomic-scale characteristics in nanoparticle self-assembly will be investigated in detail. The new framework of statistical mechanics for nanoparticle systems will be substantiated. The new nanofabrication ideas will be carefully assessed. The proposed research thus presents a range of theoretical studies that has not been attempted for the investigation of nanoparticle self-assembly.Broader impact: The proposed research will provide a comprehensive characterization and understanding of nanoparticle self-assembly at a level that has not been achieved before. Thegenerated results and insights will be useful to improve current nanofabrication avenues and to offer suggestions for future nanotechnological development. The proposal also has a strong educational component that effectively integrates the PI's research expertise into education at several levels on a continuous basis. It enriches Chemical Engineering education with molecular simulation by implementing a required undergraduate course entitled "Molecular Chemical Engineering" and a senior/graduate elective course entitled "Molecular Simulation in Engineering and Science." A Molecular Simulation Laboratory is also being developed to bring molecular simulation closer to students. These efforts are entirely new in the Department of Chemical and Biological Engineering and at the University of Missouri-Rolla, and will begin to put in place a new culture for students to look at engineering systems and problems from molecular perspectives. The PI will continue to engage undergraduate students in fundamental research and encourage them to pursue advanced studies. Two undergraduate researchers will be sponsored by the project and part of their job is to talk to high school students to promote their interest in engineering education and fundamental research. The educational plan will have a significant impact because molecular simulation has evolved into a practical tool of tremendous academic and industrial significance and because modern technologies have made molecular perspectives imperative by adopting bottom-up approaches.