NER: Anisotropic Nanocolloid Manufacturing By Nanofluidic Processing

摘要-0507839里根纳大学：各向异性纳米胶体制造纳米流体处理迈克尔J。所罗门，马克A。Burns和Joanna Mirecki Millunchick，密歇根大学将纳米胶体组装成有用的结构是纳米科学和工程新兴应用的关键。然而，由于迄今为止组装的单元电池数量少得令人不安，组装的最初影响有限。由于它们相对于球体的对称性降低，具有各向异性形状和相互作用的纳米胶体的现成可用性将提高具有新颖形态的有序阵列的组装范围。然而，生产各向异性颗粒的方法的发展仍处于起步阶段。可用的方法是费力和/或资本密集型的，并且通常既不灵活也不可扩展。在这里，我们将开发一个多功能的纳米流体平台，用于快速制造具有各向异性形状和相互作用的纳米胶体。这个探索性的项目结合了一个跨学科的团队，在粒子合成，光刻，射流和聚焦离子束（FIB）图案化方面具有强大的能力，以追求这一目标。芯片上的流体处理是一种有效的方式来引导，混合，反应和分析微量的反应物和产物。我们的目标是将纳米流体技术应用于纳米通道中单个纳米胶体的直接，顺序和链接链。有序化和连接将提供所需的形状和相互作用各向异性。纳米纤维束和FIB方法将用于构建纳米流体处理器，该处理器可以复制到并行处理器中进行大规模生产。通过合成具有不同空间层化学的聚（甲基丙烯酸甲酯）和二氧化硅的单分散纳米胶体，我们获得了具有不同潜在相互作用的可用颗粒，在此标记为纳米胶体“A”和“B”。“它们的尺寸是可控的，小到40纳米。所提出的纳米流体处理器将产生具有可变和可指定的A和B排序的连接的、永久键合的纳米胶体链。例如，我们最初的目标是生产B-B-A-A-A-A型的“纳米表面活性剂”。器械功能为：通过软件编程的压力致动序列，A和B颗粒以所需的序列交替地单列供给到窄通道。将通道横截面与颗粒直径匹配产生保持序列顺序的单列运动。然后将颗粒输送到反应区中，在反应区中，流动收缩部固定并压缩序列，使得相邻的颗粒接触。然后，表面偶联反应（由UV激发引发）将颗粒共价结合到由流体排序指定的各向异性序列中。该设备将首先在~ 500 nm的尺度上开发，以便通过双通道共聚焦荧光显微镜的原位可视化来优化流体控制和操作。然后，该器件将按比例缩小，以便使用约50 nm的构建块进行制造。我们将纳米流体应用于纳米胶体合成的想法具有智力价值，因为：（1）流体处理可以精确控制高保真合成所需的颗粒的相对取向;（2）该方案使用连续（而不是批量）处理，从而实现真正的制造能力。这些材料将用于各向异性颗粒组装的初始基础工程科学研究，这是无法以任何其他方式完成的。除了研究生教育和推广到中学女生的成果外，这项工作的更广泛影响将是建立纳米流体和纳米图案化可以应用于解决纳米胶体合成中的难题。该项目将：（1）使各向异性颗粒在学术实验室中的常规合成成为可能，从而增加了全国范围内组装研究的范围;（2）使大规模商业化制造用于化学传感和光子带隙材料等应用的特殊各向异性纳米胶体的可能性成为可能。该提案所涉及的主要研究和教育主题是“纳米级的制造过程”。"

ABSTRACT - 0507839University of MichiganNER: Anisotropic Nanocolloid Manufacturing By Nanofluidic ProcessingMichael J. Solomon, Mark A. Burns and Joanna Mirecki Millunchick, University of MichiganThe assembly of nanocolloids into useful structures is key to emergent applications of nanoscale science and engineering. Yet, the initial impact of assembly has been limited because of the disappointingly small number of unit cells assembled to date. Because of their reduced symmetry relative to spheres, ready availability of nanocolloids with anisotropic shape and interactions would improve the scope for assembly of ordered arrays with novel morphology. However, the development of methods to produce anisotropic particles is in its infancy. Methods available are laborious and/or capital intensive and often neither flexible nor scalable. Here we will develop a versatile nanofluidic platform for the rapid manufacture of nanocolloids with anisotropic shape and interactions. This exploratory project combines an interdisciplinary team with strong capabilities in particle synthesis, lithography, fluidics and focused ion beam (FIB) patterning in pursuit of this aim.On chip fluidic processing is an efficient way to direct, mix, react and analyze minute amounts of reactants and products. We aim to apply nanofluidic technology to direct, order and link chains of individual nanocolloids in nanoscale channels. The ordering and linking will provide the desired shape and interaction anisotropy. Nanofabrication and FIB methods will be used to construct a nanofluidic processor that can be replicated into parallel processors for large-scale production. Through syntheses of monodisperse nanocolloids of poly(methyl methacrylate) and silica with different steric layer chemistry, we have available particles with differing potential interactions, here labeled as nanocolloids "A" and "B." Their size is controlled and as small as 40 nm. The proposed nanofluidic processor will yield linked, permanently bonded chains of nanocolloids with ordering of A and B that is variable and specifiable. Our initial aim, for example, will be to produce a "nano-surfactant" of type B-B-A-A-A-A. The device function will be: By a software-programmed sequence of pressure actuations, A and B particles are alternately fed single-file to a narrow channel in the desired sequence. Matching the channel cross-section to the particle diameter yields single-file motion that conserves the sequence order. The particles are then conveyed into a reaction zone where a flow constriction immobilizes and compresses the sequence so that adjacent particles are in contact. A surface coupling reaction (initiated by UV excitation) then covalently binds the particles into the anisotropic sequence specified by the fluidic ordering. The device will first be developed at scales of ~ 500 nm so that fluidic control and operation can be optimized through in situ visualization with two-channel confocal fluorescence microscopy. The device will then be scaled down for manufacturing with ~ 50 nm building blocks. The products of the manufacturing will be used to perform initial assembly studies.Our idea to apply nanofluidics for nanocolloid synthesis has intellectual merit because: (1) fluidic processing allows precise control of the relative orientation of particles needed for high fidelity synthesis; (2) the scheme uses continuous (rather than batch) processing and thus achieves a true manufacturing capability. The materials will be used for initial fundamental engineering science studies of anisotropic particle assembly that could not be accomplished in any other way. In addition to the outcomes of graduate education and outreach to middle school girls, the broader impact of the work will be to establish that nanofluidics and nanopatterning can be applied to solve a difficult problem in nanocolloid synthesis. The project will: (1) make possible routine synthesis of anisotropic particles in academic laboratories, thereby increasing the scope for assembly studies nationwide; (2) render feasible the possibility of large-scale, commercial manufacturing of specialty anisotropic nanocolloids for such applications as chemical sensing and photonic band gap materials. The principal research and education theme that this proposal addresses is "Manufacturing processes at the nanoscale."