Collaborative Research: Rational Design of Ionene + Ionic Liquid Membranes Based on Understanding Gas Transport on Different Length Scales

与蒸馏和吸收等传统的化学分离过程相比，膜提供了更高的能量和操作效率。然而，膜技术不如蒸馏和吸收技术成熟。开发新的膜材料以使基于膜的分离与这些传统技术竞争仍然是一个重要的需求。化学分离是至关重要的，因为它们支撑着现代世界运转所需的能源和材料的生产。改进分离过程是降低能源消耗、产品和服务成本以及温室气体(GHG)排放的关键。该项目将利用合成化学、聚合物科学以及最先进的传输测量和光谱技术来发展膜结构和性能的新基础知识，这将导致膜性能的突破。通过膜设计过程和这些膜的结构-传输关系的发展所获得的经验教训也可以转化为其他应用，例如利用塑料废料来获得关键的起始材料，以产生具有独特性能的新的可3D打印的高性能聚合物材料。这个项目为本科生和研究生创造了各种合成和表征技术的培训机会，并利用研究人员建立的现有课程来促进本科生的参与。气体扩散在聚合物膜的分离性能中起着关键作用。然而，对气体扩散在微观上的量化和基本认识，即。亚微米和微米，长度尺度可与结构不均匀(区域)的大小相媲美的电离烯还没有被证明。该项目将解决这一知识差距，允许在详细了解微观扩散及其与整个膜的宏观传输以及膜结构特性的关系的基础上进行合理的聚合物膜设计。协同实验研究计划的主要目标是对一种新型聚合物中的气体传输有一个基本的了解，这种新型聚合物名为“双链段离子烯”(DS ION Enes)。双链离子烯的研究将为气体分离膜聚合物的设计创造一个新的范例，并产生大量的知识，这些知识也将引起分离科学和聚合物科学界的广泛兴趣。双链离子烯结构的系统变化将提供关于主要膜组分的组成、长度和体积分数如何在所有相关长度尺度上影响气体渗透和扩散的深入知识。总的目标是发展对结构-传输关系的理解，从而允许定制膜成分以使任何目标气体分离应用的性能最大化。二氧化碳(CO2)、甲烷(CH4)和一氧化碳(CO)气体将在微观扩散核磁共振实验中进行检测。宏观膜实验将考虑与能源生产和消耗有关的其他气体，包括氮、氧和氢。该项目的成功将转化为在制造用于气体分离的高渗透和高选择性聚合物膜的能力方面的重大智力进步，这将是应对21世纪能源挑战所必需的。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。

Membranes offer improved energy and operational efficiency compared to traditional chemical separation processes such as distillation and absorption. However, membrane technology is less mature than distillation and absorption technologies. Developing new membrane materials to make membrane-based separations competitive with these traditional technologies remains a significant need. Chemical separations are of vital importance as they underpin the production of energy and materials that allow the modern world to function. Improvements to separation processes are key to reducing energy consumption, costs of products and services, and greenhouse gas (GHG) emissions. This project will utilize synthetic chemistry, polymer science, and state-of-the-art transport measurement and spectroscopic techniques to develop new fundamental knowledge of membrane structures and performance, which can lead to breakthroughs in membrane performance. The lessons learned through the membrane design process and the development of structure-transport relationships for these membranes can also be translated to other applications, such as utilizing plastic wastes to obtain key starting materials in the generation of new high-performance polymer materials with unique properties that can be 3D printed. This project creates opportunities for training undergraduate and graduate students in a variety of synthetic and characterization techniques and leverages existing programs established by the investigators to facilitate undergraduate student participation.Gas diffusion plays a key role in the separation performance of polymer membranes. Yet, quantification and fundamental understanding of gas diffusion on microscopic, viz. sub-micrometer and micrometer, length scales comparable with sizes of structural inhomogeneities (domains) have not been demonstrated for ionenes. This project will address this knowledge gap, allowing for rational polymer membrane design based on a detailed understanding of microscopic diffusion and its relationship with the macroscopic transport through an entire membrane as well as membrane structural properties. The key objective of the synergistic experimental research plan is to develop a fundamental understanding of gas transport in a new type of polymer named “doubly segmented ionenes” (DS ionenes). The study of DS ionenes will create a new paradigm for the design of polymers for gas separation membranes and generate a significant body of knowledge that will also be of broad interest to the separation science and polymer science communities. The systematic variation of DS ionene structures will provide deep knowledge of how the composition, length, and volume fraction of major membrane constituents influence gas permeability and diffusion on all relevant length scales. The overall goal is to develop an understanding of the structure-transport relationship that allows for tailoring membrane composition to maximize performance for any target gas separation application. Carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) gases will be examined in microscopic diffusion NMR experiments. Additional gases related to energy production and consumption, including nitrogen, oxygen, and hydrogen, will be considered in the macroscopic membrane experiments. The success of this project will translate into major intellectual advancements in the ability to build high-permeability and high-selectivity polymer membranes for gas separations, which will be required to meet the energy challenges of the 21st Century.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.