Development of Microfluidic Reactor for Continuous Production of Monosized Nanocrystals

本研究的目的是进行所需的理论研究，以设计一个微流控反应器，用于在工业规模上合成纳米晶体，用于纳米晶体的使用点制造，或探测其形成过程中发生的过程。许多单独的微反应器，包括它们的试剂引入系统和流动通道，可以包含在单个绝缘体上硅晶片中，允许并行化，以及合成和制造中前所未有的控制和可扩展性。该方法是采用两种不混溶的液体，具有诱导自发产生分散在另一相中的一相液滴的通道几何形状。 然后这些液滴将以严格控制的停留时间通过反应器。反应器内的各个区域将被加热以促进化学反应，从而导致半导体纳米晶体的成核。 然后，核将流到其他较冷的区域，在那里不会发生进一步的成核，但现有的核可以生长以实现所需的颗粒特性。第一阶段的工作将是芯片设计、微流体现象以及微流体形成和演化的综合建模。第二部分是建立稳定的两相流模型，优化微反应器流道结构。 第三部分将利用模型硒化镉体系完成对纳米晶体合成的热化学和动力学描述，并创建一个“虚拟”反应器。该研究解决了将“纳米革命”的好处扩展到普通公众的最严重障碍之一，即我们目前无法制造出可用于商业应用的大量纳米晶体。如果没有这一关键的踏脚石，大量的基础研究已经确定了纳米晶体的无数应用将被浪费。该研究还将通过工程学院的SUPERB计划为历史上代表性不足的工程本科生提供研究经验。

The objective of this research is to conduct the theoretical studies needed to design a microfluidic reactor for synthesizing nanocrystals on an industrial scale, for point-of-use manufacture of nanocrystals, or to probe the processes occurring during their formation. Numerous individual microreactors, including their reagent introduction systems and flow channels, could be contained in a single silicon-on-insulator wafer, allowing parallelization, and unprecedented control and scalability in synthesis and manufacturing. The approach is to employ two immiscible liquids, with a channel geometry that induces spontaneous generation of droplets of one phase dispersed in the other. These droplets will then pass through the reactor with a tightly controlled residence time. Individual zones within the reactor will be heated to promote chemical reactions leading to the nucleation of semiconducting nanocrystals. The nuclei will then flow to other, cooler zones where no further nucleation could occur, but existing nuclei could grow to achieve desired particle characteristics. The first phase of work will be integrated modeling of the chip design, microfluidic phenomena, and nanocrystal formation and evolution. The second will model the stable two-phase flow, and optimize the microreactor flow channel configuration. The third will complete the thermochemical and kinetic description of nanocrystal synthesis, using the model cadmium selenide system, and create a "virtual" reactor.The research addresses one of the most serious barriers to extending the benefits of the "nanorevolution" to the general public, namely our current inability to manufacture nanocrystals in quantities that are realistic for commercial applications. Without this crucial stepping-stone to manufacturing, the vast amount of fundamental research that has identified innumerable applications of nanocrystals would be wasted. The research will also offer research experiences to historically under-represented engineering undergraduates through the College of Engineering's SUPERB program.