SGER: Nanoparticle Shape Formation Mechanisms in Gas Phase Synthesis

摘要CTS-0423621Y。密苏里州大学的XING-ROLLA纳米颗粒已经成为纳米技术研发中的一类重要材料。众所周知，纳米颗粒的大小依赖于其性质，这使得控制其电子、光学、化学和机械性质成为可能。事实上，在过去的二十年里，在合成尺寸可控的纳米粒子方面进行了大量的研究活动。虽然尺寸是控制纳米粒子性能的一个重要因素，但最近在合成形状可控纳米粒子方面的成功展示了纳米粒子的另一个有趣的方面，即形状可控性能。本研究的目的是探索气相法制备的纳米氧化铁颗粒的形态形成机理。通过使用专门设计的逆流扩散火焰反应器进行实验，结合纳米粒子在热边界层中沉积的理论方法，我们的目标是对气相纳米粒子形状的形成有一个基本的了解，并了解在沉积过程中纳米粒子形状的形成是否由于纳米粒子的结晶，如果是的话，它是如何受到热边界层的影响的。我们最近在气相合成氧化铁纳米颗粒方面的结果表明，一种更有利的方法来制备形状可控的纳米颗粒。这项探索性研究将是对气相过程中纳米颗粒形状形成的基本了解的第一次尝试。这样的研究对于提高我们控制和优化形状可控纳米颗粒的气相合成技术的能力是必要的。通过拟议的研究，将在纳米颗粒合成以及纳米颗粒动力学和热边界层中的传输方面创造新的知识。拟议中的研究如果成功，将为未来气相合成形状可控纳米颗粒的多年项目奠定基础。布罗德影响纳米技术正迅速成为经济增长的关键使能技术之一。本项目提议的一项基础性研究将使开发更高效、成本更低的纳米材料生产工艺成为可能。因此，拟议的项目将产生重大的社会和经济影响。该项目将涉及研究生和本科生的综合研究和教育。本科生将通过他们的独立研究课程积极参与到这个项目中来。研究生将在建议的领域通过论文研究获得培训。一名高中生也将通过密苏里大学罗拉分校的暑期项目参与其中。为了广泛传播新的知识和经验，这项工作的成果将在专业会议上提出，在同行审查的期刊上发表，并在万维网上提供。

AbstractCTS-0423621Y. Xing, U of Missouri-RollaNanoparticles have become an important class of materials in nanotechnology research and development. The well-known, size-dependent properties of nanoparticles make it possible to control their electronic, optical, chemical, and mechanical properties. Indeed, over the past two decades there has been enormous research activity in the synthesis of size-controlled nanoparticles. While the size is an important factor in controlling nanoparticle properties, the recent success in the synthesis of shape-controlled nanoparticles has demonstrated yet another interesting aspect in nanoparticles, i.e., shape-controlled properties. The objective of this research is to explore the shape formation mechanisms of iron oxidenanoparticles synthesized in a gas-phase process. By conducting experiments using a specially designed counterflow diffusion flame reactor, together with theoretical approaches to nanoparticle deposition in thermal boundary layers, we aim to obtain a fundamental understanding of gas-phase nanoparticle shape formation and to learn if the shape formation is due to nanoparticle crystallization during the deposition process, and if so, how it is affected by the thermal boundary layers.Intellectual meritThe synthesis of shape-controlled nanoparticles had been achieved only in liquid phase before. Our recent results in the gas-phase synthesis of iron oxide nanoparticles demonstrated a more favorable way of producing shaped-controlled nanoparticles. This exploratory research will be the first attempt to gain a fundamental understanding of nanoparticle shape formation in gasphase processes. Such research is necessary to increase our ability to control and optimize the gas-phase synthesis technique for shape-controlled nanoparticles. Through the proposed study, new knowledge will be created in nanoparticle synthesis, as well as in nanoparticle dynamics and transport in thermal boundary layers. The proposed research, if successful, will establish the foundation for a future, multi-year project in the gas-phase synthesis of shape-controlled nanoparticles.Broader ImpactsNanotechnology is fast becoming one of the key enabling technologies for economic growth. A fundamental study as proposed in this project will enable the development of more efficient and less costly processes for nanomaterials production. Therefore, the proposed project would have significant societal and economic impacts. The project will involve integrated research and education for both graduate and undergraduate students. Undergraduate students will be actively involved in the project through their independent research class. Graduate students will obtain their training through thesis research in the proposed area. A high school student also will be involved through a summer program at the University of Missouri-Rolla. In order to broadly disseminate new knowledge and experience, results from this work will be presented at professional meetings, published in peer-examined journals, and made available on the World Wide Web.