NIRT: Manufacturing of Novel Continuous Nanocrystalline Ceramic Nanofibers with Superior Mechanical Properties

本提案是对NSF 01-157 NIRT类纳米科学与工程倡议的响应。具有特殊和极端性质的纳米结构材料(NSM)将在许多新兴技术中发挥关键作用。然而，制造具有所需性能的NSM是非常复杂的，目前过度依赖经验数据。在这项提案中，将讨论一种新的制造工艺，以生产一种新型的陶瓷材料，即连续陶瓷纳米纤维。最近由两位PI(Dzenis和Larsen)发明的新型Sol-Gel电纺丝技术(美国专利正在申请中)可以生产具有潜在极端热机械性能的亚微米直径的陶瓷纤维。这项技术将在综合、多学科研究的基础上进行分析和优化，以生产具有优异机械性能的纳米晶陶瓷纳米纤维。该研究小组将开发一种高效而稳健的计算方法，以模拟真实的纳米晶体纳米纤维及其在有限温度下的机械响应。一种新的基于蒙特卡罗混合有限元技术的原子-连续介质建模方法将被开发和使用。通过预测晶界和缺陷的化学成分和原子结构对力学性能的影响，这些模型将被应用于设计强大的纳米纤维。这些结果将被用于发展化学，并指导制造坚固的纳米晶纳米纤维。利用基于扫描探针显微镜的新的机械表征技术，将通过实验证明所得到的纳米纤维的机械性能得到了增强。作为本研究的结果，新的纳米制造方法将在原子-连续模型的基础上进一步发展。将生产出具有优异力学性能的新型纳米晶陶瓷纳米纤维。结合制造和基于模型的优化将允许纳米纤维的机械性能根据最终用户的特定需求进行量身定制。这种通用的、建模驱动的方法将适用于其他纳米制造过程和纳米材料。这项技术将是未来纳米技术努力的重要组成部分。这项研究计划将影响纳米技术的其他关键领域，如用于超滤和其他分离过程的纳米结构膜、用于纳米复合材料的纳米强化元件、用于纳米结构催化剂的载体等。多学科教育计划将包括开发关于材料合成技术、计算材料科学和纳米材料表征的跨学科研究生课程。研究生和本科生的研究助理将在研究的计算和实验方面在不同的研究小组中工作。与国家实验室研究人员的计划互动将为研究生和本科生提供额外的教育机会。

This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NIRT. Nanostructured materials (NSMs) with unusual and extreme properties will play a key role in many emerging technologies. However, manufacturing of NSMs with the desired properties is highly complex and currently is over-reliant on empirical data. In this proposal, a novel manufacturing process producing a new class of ceramic materials, i.e. continuous ceramic nanofibers, will be addressed. The novel sol-gel electrospinning technique (U.S. patent pending), invented recently by two of the PI's (Dzenis and Larsen), produces ceramic fibers of submicron diameters with potentially extreme thermomechanical properties. This technique will be analyzed and optimized for the production of nanocrystalline ceramic nanofibers with superior mechanical properties, based on a comprehensive, multidisciplinary research effort. The research team will develop an efficient and robust computational methodology for simulating realistic nanocrystalline nanofibers and their mechanical response at finite temperatures. A novel atomistic-continuum modeling approach based on a hybrid Monte-Carlo finite element technique will be developed and used. The models will be applied to design strong nanofibers by predicting the effects of the chemical composition and atomic structures of grain boundaries and defects on mechanical properties. The results will be used to develop chemistry and to direct manufacturing of strong nanocrystalline nanofibers. The achievement of the enhanced mechanical properties of the resulting nanofibers will be demonstrated experimentally utilizing novel mechanical characterization techniques based on scanning probe microscopy. As a result of this research, the new nanomanufacturing method will be further developed based on the atomistic-continuum modeling. New nanocrystalline ceramic nanofibers with superior mechanical properties will be produced. The combined manufacturing and model-based optimization will allow the mechanical properties of the nanofibers to be tailored to specific needs of the end user. This general, modeling-driven approach will be applicable to other nanomanufacturing processes and nanomaterials. This technology will be a significant part of future nanotechnology efforts. This research program will impact other key areas of nanotechnology where radical improvement of mechanical properties is critical, e.g., nanostructured membranes for ultrafiltration and other separation processes, nanoreinforcing elements for nanocomposites, supports for nanostructured catalysts, and many others. A multidisciplinary education plan will include development of interdisciplinary graduate courses on materials synthesis technology, computational materials science, and nanoscale materials characterization. Graduate and undergraduate research assistants will work within the various research groups on computational and experimental aspects of the research. Planned interactions with researchers at national laboratories will provide graduate and undergraduate students with additional educational exposure.