Development of High Performance Gas Separation Membranes through Intelligent Catalyst and Monomer Design

Polymer membranes are a valuable tool for separating components of liquid and gas mixtures. Heavily inspired by biological systems, the idea of using the intrinsic properties of polymers to perform otherwise energy-intensive tasks is attractive for applications such as water desalination, natural gas sweetening, and post-combustion carbon capture. Of particular interest to our research group, post-combustion carbon capture is a promising potential solution aimed at reducing the carbon footprint involved with production, transportation, and storage of electrical energy generation.

Every year, the United States produces close to seven billion metric tons of carbon dioxide, of which a significant portion is generated by coal-fired power plants. With a lack of significant research breakthroughs in renewable energy sources, the continued use of coal is necessary to maintain current energy demands. To consume this resource responsibly, researchers continue to develop methods to minimize the release of greenhouse gas emissions from the combustion of coal and other fossil fuels. Polymer membranes offer an industrially scalable solution that can be easily implemented into existing infrastructure and operate at a fraction of the cost of other possible carbon sequestration solutions. However, implementing membrane solutions for this particular gas separation is extremely demanding in terms of chemical stability, thermal stability, and raw membrane performance, which requires materials designed specifically for this application.

Described herein, is a body of work directed towards the synthesis of new materials that have not been investigated for the separation of carbon dioxide and nitrogen previously. Throughout the membrane design, we chose to emphasize polymer structures with rigid backbones, significant mechanical integrity, and polar functionality that will be attracted towards carbon dioxide more so than nitrogen. These macromolecules were made via different polymerization techniques and required specific catalyst design in order to obtain the desired functionality. The results are polymer membranes that have some of the highest performance for the separation of carbon dioxide and nitrogen while maintaining a unique combination of excellent processability, mechanical strength, thermal stability, and optical transparency that could be useful in other engineering applications.