Crosslinked Membranes with Non-Collapsible, Uniform Pores of Sub-nanometer Size

1066947Gong 具有精确控制直径的不可变形孔隙的有机纳米管非常罕见。这项研究旨在基于化学合成、自组装、纳米多孔膜的制造以及计算建模和优化，创建具有可修改表面和不可变形的亚纳米孔的刚性纳米管的稳健组装。要创建的纳米管是环形分子的圆柱形堆叠。该方法的巨大潜力在于其控制或调节亚纳米孔或纳米孔的尺寸和功能的能力。越来越清楚的是，直径减小的通道，特别是亚纳米范围内的通道，可以完全排斥金属离子，同时仍然允许水通过。所提出的方法还允许将额外的化学物质引入亚纳米孔中，预计这些孔将表现出非常有效的水传输和非常高的离子选择性，因此可以克服开发能够与天然膜相媲美的人造膜的最后一个主要障碍。这些自组装孔隙可以进行微调，以排斥盐、离子或水特征，这对于目前已知的合成孔隙来说是前所未有的。这些结构简单、易于合成、直径可调节、完全单分散的纳米孔的出现，将为制造高效、实用的膜开辟一条新途径，其应用范围从水净化到各种分子的分离。该研究的智力价值在于整合了多个科学领域的概念，包括用于纳米多孔膜制造的有机、无机、超分子、物理和聚合物化学。除了所提出的制造具有均匀尺寸的纳米孔的膜的策略所提供的巨大潜力之外，该项目还代表了一种构建具有亚纳米孔的膜的新的、现实的方法，这应该解决膜科学中的主要挑战之一。开发纳米级分子和超分子化学，以及相应的纳米管组件及其进一步的工程设计，应该为理解纳米尺度上的分子和超分子相互作用做出基础贡献，从中获得的见解将极大地促进下一代新型纳米结构的开发。这项研究更广泛的影响涉及其高度跨学科的性质，在此基础上，不同背景的学生将获得多个领域的技能，包括化学、材料科学以及相应分子和器件的工程。具体来说，这项研究的教育影响包括：（1）将分子、超分子和纳米结构的计算机辅助设计、合成和表征与所得材料和设备的工程相结合来培训研究生的机会； (2) 拟议的研究涵盖广泛的背景和技能，因此特别适合本科生的参与。 PI已经并将继续积极努力，通过多种渠道从传统上代表性不足的科学群体中招收本科生。其中包括 NSF-REU 项目、SUNU Buffalo 的大学科学技术入门项目 (CSTEP)、与该地区本科院校建立的合作，以及 PI 近年来教授的大二有机化学课程； （3）研究成果将发表在知名度较高的期刊上，以向整个科学界广泛传播这项工作，并将带来许多实际应用。从对环境具有重要意义且紧迫的水净化和海水淡化问题中获得的见解（这是本应用的重点）将有助于开发通常可用于解决化学和生物分离领域的其他问题的概念。

1066947GongOrganic nanotubes with non-deformable pores of precisely controlled diameters are rare. This research aims to create robust assembly of rigid nanotubes with modifiable surfaces, and a nondeformable, sub-nanometer pores, based on chemical synthesis, self-assembly, fabrication of nanoporous membranes, and computational modeling and optimization. The nanotubes to be created are cylindrical stacks of donut-like molecules. The great potential of the proposed method lies in its ability to control or tune the size and function of a sub-nanometer pore or nanopore. It is becoming increasingly clear that channels of reduced diameters, particularly those in the sub-nm range, may completely reject metal ions while still allowing water to pass through. The proposed method also allows additional chemistry to be introduced into the subnanometer pores, which are expected to demonstrate very efficient water transport and remarkably high ion selectivities and could therefore overcome the last major hurdle in developing artificial membranes capable of rivaling their natural counterparts. These selfassembling pores may be fine tuned to repel salt, ions, or water features that are unprecedented for currently known synthetic pores. The availability of these structurally simple, synthetically readily available nanopores with tunable, perfectly monodisperse diameters should open a new avenue to the fabrication of highly efficient, practical membranes for applications ranging from water purification to separations of various molecules. The intellectual merit of the proposed research lies in the integration of concepts from multiple scientific fields including organic, inorganic, supramolecular, physical, and polymer chemistry for nanoporous membrane fabrication. Besides the tremendous potentials provided by the proposed strategies for fabricating membranes with nanopores of a uniform size, this project represents a new, realistic approach for constructing membranes having sub-nanometer pores, which should address one of the major challenges in membrane science. Developing the nanoscale molecular and supramolecular chemistry, along with the corresponding nanotubular assemblies and their further engineering should make fundamental contribution to the understanding of molecular and supramolecular interactions on the nanometer scale, insights from which should greatly facilitate the development of novel nanostructures of the next generation. The broader impact of this research involves its highly interdisciplinary nature, based on which students of various backgrounds will gain skills in multiple fields including chemistry, materials science and the engineering of the corresponding molecules and devices. Specifically, the educational impacts of this research include: (1) The opportunity to combine computer-aided design, synthesis, and characterization of molecular, supramolecular, and nanosized structures with the engineering of the resultant materials and devices in training graduate students; (2) the proposed research encompasses a broad range of background and skills and will thus be especially suitable for the participation of undergraduate students. Aggressive efforts have been successfully, and will be continuously, made by the PI to recruit undergraduate students from groups of traditionally underrepresented groups in sciences, from multiple channels. These include the NSF-REU program, the Collegiate Science and Technology Entry Program (CSTEP) at SUNU Buffalo, established collaborations with undergraduate institutions in the area, and the sophomore-level organic chemistry course the PI has been teaching in recent years; (3) the research results will be published in highly visible journals to broadly disseminate this work to scientific society at large, and will lead to many practical applications. Insights obtained from the environmentally significant and urgent problem of water purification and desalination, which is the focus of this application, will help the development of concepts that are generally useful for addressing other problems in the field of chemical and biological separation.