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

该提案是响应纳米科学与工程倡议，NSF 01-157，类别NIRT。具有特殊和极端特性的纳米结构材料（NSMs）将在许多新兴技术中发挥关键作用。然而，具有所需性质的NSM的制造是高度复杂的，并且目前过度依赖于经验数据。在该提案中，将解决生产新型陶瓷材料，即连续陶瓷纳米纤维的新型制造工艺。新的溶胶-凝胶静电纺丝技术（美国专利申请中），最近发明的两个PI的（Dzenis和拉森），生产陶瓷纤维的亚微米直径具有潜在的极端热机械性能。该技术将进行分析和优化，以生产具有上级机械性能的纳米晶陶瓷纳米纤维，基于全面的，多学科的研究工作。该研究小组将开发一种有效和强大的计算方法，用于模拟现实的纳米晶纳米纤维及其在有限温度下的机械响应。将开发和使用一种基于混合蒙特-卡罗有限元技术的新的原子连续体建模方法。该模型将被应用于设计强大的纳米纤维，通过预测的化学成分和原子结构的晶界和缺陷的机械性能的影响。研究结果将用于开发化学和直接制造强纳米晶纳米纤维。实验证明，利用基于扫描探针显微镜的新的机械表征技术，所得纳米纤维的增强的机械性能的实现。作为本研究的结果，新的纳米制造方法将进一步发展的基础上原子连续建模。将产生具有上级机械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定制。这种通用的建模驱动方法将适用于其他纳米制造工艺和纳米材料。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，其中机械性能的根本改善至关重要，例如，用于超滤和其它分离过程的纳米结构膜、用于纳米复合材料的纳米增强元件、用于纳米结构催化剂的载体以及许多其它材料。一个多学科的教育计划将包括材料合成技术，计算材料科学和纳米材料表征的跨学科研究生课程的发展。研究生和本科生研究助理将在研究的计算和实验方面的各个研究小组内工作。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.