Synthetic Control over MOF Particle Growth and Surface Chemistry

非技术概述基于金属有机骨架(MOF)的膜是一种三维(3D)有机/无机化合物，由于其特殊的可调性和合成多样性，在工业炼油和气体分离方面引起了人们的浓厚兴趣。然而，要使MOF在工业部门获得广泛的吸引力和实施，研究人员将被要求超越三维MOF，开发新型的MOF纳米颗粒，因为它们表现出优异的分离性能，并生成具有优异稳定性的膜。在过去的二十年里，MOF的块状粉末一直是MOF学术研究的重点，但最近人们的注意力转向了制备MOF纳米颗粒和精确控制颗粒尺寸的聚合物复合材料。尽管初步证明了MOF纳米颗粒的巨大潜力，但对于实现对MOF颗粒组成的可重复控制以及了解颗粒尺寸和组成如何影响膜性能，关键的基本问题仍然存在。在NSF材料研究部固态和材料化学计划的支持下，俄勒冈大学的Carl Brozek教授和他的研究小组将研究控制MOF纳米晶体精确尺寸和组成的化学原理。机械生长模型将在为其他类别的材料建立的生长模型的背景下开发，以便这些结果为材料化学的广泛领域提供信息。同样，这项提案中追求的合成技术将通过概述分子控制多种尺寸范围内的材料的基本工具，来影响MOF颗粒以外的材料设计。这项拟议的研究具有实际的社会意义，因为对MOF纳米晶尺寸的精确控制将为工业改进的气体分离膜开辟新的前沿，并将MOF的应用性能提升到实际意义上的机会。技术概述该项目由美国国家科学基金会材料研究部的固态和材料化学计划支持，将研究金属有机骨架(MOF)颗粒的基本生长机制，开发控制颗粒表面化学以提高其胶体稳定性和与聚合物复合材料接口的方法，并了解尺寸和表面组成对分子和电荷传输特性的影响。要实现这一目标，需要对决定颗粒大小、缺陷掺入和表面功能化的参数进行基础研究。这项研究将有助于全面控制材料的晶核生长，实现MOF基异质结构复合材料的可重复合成，提高MOF材料的实用价值。这项提议的更广泛的影响包括1)将这些研究目标整合到教育推广活动中，向服务不足的学生传播碳捕获技术的科学；2)促进将化学与建筑学学生配对设计空气净化模块的跨学科培训计划；3)赞助基于MOF的碳捕获的产业界-学术界研讨会系列；以及4)实施一项针对俄勒冈大学(UO)化学博士生的设计推广计划的教学课程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical SummaryMembranes based on metal-organic frameworks (MOFs), which are three-dimensional (3-D) organic/inorganic compounds, attract intense interest for industrial petroleum refining and gas separations due to their exceptional tunability and synthetic diversity. For MOFs to reach widespread attraction and implementation in the industrial sector, however, researchers will be required to go beyond 3-D MOFs and develop new types of MOF nanoparticles, as they exhibit superior separation performance and generate membranes with superior stability. For the past two decades, bulk powders of MOFs occupied the focus of academic MOF research, but very recent attention has turned to preparing MOF nanoparticles and polymer composites with precise control of particle sizes. Despite preliminary demonstrations of the great potential of MOF nanoparticles, key fundamental questions remain for achieving reproducible control over MOF particle composition and for understanding how particle size and composition impact membrane performance. With this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, Prof. Carl Brozek at the University of Oregon and his research group will investigate the chemical principles that control the precise sizes and compositions of MOF nanocrystals. Mechanistic growth models will be developed in the context of growth models established for other classes of materials so that these results inform the broad field of materials chemistry. Similarly, the synthetic techniques pursued in this proposal will influence materials design beyond MOF particles, by outlining fundamental tools for molecular control over materials across multiple size regimes. The proposed research is practically relevant to society because precise control over MOF nanocrystal sizes will open new frontiers in improved gas separation membranes for industry and the opportunity for elevating MOF application performance to becoming practically relevant. Technical Summary This project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, will investigate the fundamental growth mechanisms of metal-organic framework (MOF) particles, develop methods to control particle surface chemistry for enhancing their colloidal stability and interfacing with polymer composites, and understand the impact of size and surface composition on molecular- and charge-transport properties. Tackling this goal will require basic investigation into the parameters that dictate particle sizes, defect incorporation, and surface functionalization. Insight into controlling prenucleation crystal growth of materials in general, reproducible synthesis of MOF-based heterostructure composites, and improving the practical relevance of MOF materials will result from this research. Broader impacts of this proposal include 1) integrating these research aims into educational outreach initiatives that communicate the science of carbon capture technology to underserved students, 2) fostering interdisciplinary training programs that pairs chemistry with architecture students to design air-purification modules, 3) sponsoring industry-academia seminar series on MOF-based carbon-capture, and 4) implementing a teaching course on designing outreach initiative offered year-round to University of Oregon (UO) chemistry PhD students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.