Critical Factors Controlling Gas Separations by Polymeric Membranes

非技术总结该奖项支持理论、计算和数据密集型研究和教育，旨在使用计算和数据密集型方法帮助开发用于分离气体的聚合物膜。PI将开发计算工具，模拟由长链分子组成的聚合物制成的材料。这些工具将与其他理论、数据中心和计算方法结合使用，以促进对聚合物材料的理解，并为当前和新兴的技术应用开发强大的聚合物膜设计方法。这项工作的一个亮点是使用聚合物膜来清除气流中不必要的污染物，例如从气流中去除腐蚀性的硫基化合物，以减轻长距离泵送水力压裂气体时的管道腐蚀。这些研究活动与广泛的教育活动相结合。在国际学生联合会最近成功招收高中生和本科生进行暑期研究的推动下，国际学生联合会将继续努力在本科生和研究生水平上招募女性和少数族裔学生。重点将是为高中生提供在这个项目中进行暑期研究的机会。受到过去成功的鼓舞，这些高中生将被积极鼓励继续本科教育，最终可能在STEM就业。技术总结该奖项支持理论、计算和数据密集型研究，以及促进对聚合物膜的理解的教育。聚合物膜对于气体分离应用是有效的，它还有另外的优点，即重量轻，易于加工。聚合物膜材料有许多进展，但大多数都是经验性设计的。为了制定设计策略，需要定量地了解控制分子传输、溶解度以及这些材料的渗透性和选择性的微观机制。PI将使用计算机模拟和数据密集型方法来解决本主题中一些最重要的悬而未决的问题。该奖项支持主要使用分子动力学模拟和机器学习方法来解决三个重要问题的研究：(I)数据密集型方法能否用于设计感兴趣的膜材料？更具体地说，数据挖掘和机器学习能否被用来预测渗透率和选择性，从而预测膜气体分离性能的上限相关性？(Ii)已经发现，橡胶聚合物的渗透率对溶质大小的依赖关系与其玻璃类似物的情况“相反”。这是一种总的趋势吗？如果是这样，如何从筛分主导的玻璃化趋势过渡到可能由溶解度效应驱动的橡胶行为？以及(Iii)在气体分离的背景下，当纳米粒子与聚合物物理混合时，其作用是什么？如果使纳米颗粒具有选择性，这种现象会受到怎样的影响？在这种情况下，纳米粒子在聚合物玻璃老化中的作用是什么？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。

NONTECHNICAL SUMMARYThis award supports theoretical, computational, and data-intensive research, and education with an aim to use computation and data-intensive approaches to help develop membranes made of polymer to be used to separate gases. The PI will develop computational tools modelling materials made of polymers which are composed of long-chain molecules. These tools will be used in conjunction with other theoretical, data-centric, and computational methods to advance understanding of polymeric materials and to develop robust design methodologies for polymer membranes for current and emerging technological applications. A highlight of the work focuses on using polymer membranes to clean gas streams of unnecessary pollutants, for example removing corrosive sulfur-based compounds from gas streams to mitigate pipeline corrosion when fracked gases are pumped over long distances. These research activities are coupled to extensive educational activities. Driven by the PI's recent success in recruiting high school and undergraduate students for summer research, the PI will continue his efforts to recruit women and minority students at both the undergraduate and graduate levels. A focus will be to provide high school students with opportunities to perform summer research in this project. Encouraged by past successes, these high-school students will be actively encouraged to pursue undergraduate education leading to possible careers in STEM.TECHNICAL SUMMARYThis award supports theoretical, computational, and data-intensive research, and education to advance understanding of polymeric membranes. Polymeric membranes, which are efficient for gas separation applications, have the added advantages of being lightweight and easily processable. There have been many advances in polymer membrane materials, but most of these have been empirically designed. To develop design strategies, there is need for a quantitative understanding of the microscopic mechanisms controlling molecular transport, solubility, and hence permeability and selectivity of these materials. The PI will use computer simulations and data-intensive approaches to target some of the most important unresolved questions in this topic.This award supports research which will primarily use molecular dynamics simulations and machine learning methodologies to address three important questions: (i) Can data-intensive methods be applied to design membrane materials of interest? More specifically, can data mining and machine learning be used to predict permeability and selectivity, and thus the upper bound correlation for membrane gas separation performance? (ii) It has been found that the solute size dependence of permeability in the case of rubbery polymers is "opposite" to that found in their glassy analogs. Is this a general trend, and if so, how does the transition from glassy trends, dominated by sieving, to rubbery behavior, which is probably driven by solubility effects, occur? and (iii) What is the role of nanoparticles when they are physically mixed with polymers in the context of gas separation? How is this phenomenon affected if the nanoparticles are made selective? What is the role of nanoparticles in aging of polymer glasses in this context?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.