NER: Microfluidic-Enabled Synthesis of Nanoparticles and Hierarchical NanoClusters

美国国家科学基金会-活性纳米结构和纳米系统（NSF 05-610）纳米尺度探索性研究（NER）摘要申请号：0608864首席研究员：Anna， shelley合作单位：卡内基梅隆大学NER：微流控合成纳米颗粒和层系纳米簇这项资助是为了开发一种新型的基于微流控的技术来形成金属和半导体纳米颗粒。将开发一种新颖的、分层的和主动的制造工艺，在这种工艺中，高度单分散的纳米颗粒可以以连续和稳健的方式生产。该方法以最近的微流体乳化方法为中心，但利用液-液界面表面活性剂的存在来形成比宿主装置小几个数量级的液滴。具体来说，将使用尖端流现象来产生连续的亚微米液滴流。用于纳米颗粒合成的反应物流将被封装在所得到的亚微米液滴中，并随后在液滴内反应形成高度单分散的纳米颗粒（1-10纳米）。使用亚微米液滴作为纳米颗粒反应器的两个主要优点是：(1)亚微米长度尺度允许非常有效的扩散混合，最大限度地减少对额外混合方案的需求，并使反应动力学得以隔离；(2)由此产生的微小反应器体积导致单个纳米反应器内的反应物供应有限，从而可以精确控制形成的纳米颗粒的数量和大小。此外，在微流体装置中容易调节流动和反应条件的能力导致了固有的活性纳米级工艺。从这些研究中获得的基础知识将极大地促进微反应器和纳米颗粒技术领域不断增长的知识体系。这项探索性研究的结果将为其他新型纳米结构的合成提供额外的纳米制造工艺，包括纳米合金和由同心或顺序液滴反应器形成的纳米团簇，用于系统、组合研究纳米颗粒化学的高通量筛选设备，以及在亚微米反应器中使用纳米结构水凝胶来增强纳米颗粒的均匀性，同时最大限度地减少聚集。这项工作的广泛影响包括所提出的方法实现广泛应用的巨大潜力。特别是，这种方法可以利用广泛的可能的材料和化学物质，并且可以合成广泛的新型纳米结构。此外，PI的教育和推广活动将以消除对纳米技术的普遍误解为中心，并将利用微流体的高度视觉特性来吸引不同年龄、性别和种族的观众。

National Science Foundation - Active Nanostructure and Nanosystems (ANN) (NSF 05-610)Nanoscale Exploratory Research (NER)ABSTRACTProposal Number: 0608864Principal Investigator: Anna, ShelleyAffiliation: Carnegie Mellon UniversityNER: Microfluidic-Enabled Synthesis of Nanoparticles and Heirarchial NanoClustersThis grant is to develop a new type of microfluidic-based technique for formation of metal and semiconductor nanoparticles. A novel, hierarchical and active manufacturing process in which highly monodisperse nanoparticles can be produced in a continuous and robust fashion will be developed. The method centers on recent microfluidic emulsification methods, but exploits the presence of surfactants at liquid-liquid interfaces to bring about the formation of droplets orders of magnitude smaller than the host device. Specifically, the tipstreaming phenomenon will be used to produce a continuous stream of submicron droplets. The reactant streams for nanoparticle synthesis will be encapsulated in the resulting submicron droplets, and will subsequently react to form highly monodisperse nanoparticles (1-10 nm) within the droplets. Two key advantages of using submicron droplets as nanoparticle reactors are that (1) submicron length scales allow for very effective diffusive mixing, minimizing the need for additional mixing schemes and enabling reaction kinetics to be isolated, and (2) resulting tiny reactor volumes lead to limited reactant supply within a single nanoreactor, allowing precise control over the number and size of nanoparticles formed. Furthermore, the ability to easily tune flow and reaction conditions inline in microfluidic devices leads to an inherently active nanoscale process. The fundamental knowledge gained from these studies will significantly contribute to a growing body of knowledge in the area of microreactor and nanoparticle technology. The results of this exploratory research will enable additional nanomanufacturing processes for synthesis of other novel nanostructures, including nano-alloys and nano-clusters controlled by the formation of concentric or sequential droplet reactors, high throughput screening devices for systematic, combinatorial study of nanoparticle chemistries, and the use of nanostructured hydrogels within submicron reactors to enhance nanoparticle uniformity while minimizing aggregation. The broader impacts of this work include the significant potential for the proposed method to realize wide application. In particular, a wide range of possible materials and chemistries can be utilized with this method, and a wide range of novel nanostructures can be synthesized. In addition, educational and outreach activities of the PI's will center on dispelling common misconceptions about nanotechnology, and will utilize the highly visual nature of microfluidics to appeal to audiences that are diverse in age, gender, and ethnicity.