I-Corps: Membrane Materials for Efficient Gas and Vapor Separations

The broader impact/commercial potential of this I-Corps project is the development of a membrane technology for industrial gas and vapor separations. Effective membrane separation technology has the potential not only to reduce the energy consumption of chemical industries and accelerate the adoption of green alternative energy sources, but also to mitigate the emission of greenhouse gases.

Replacing existing energy-intensive processes with membranes may reduce annual U.S. energy costs by $4 billion and eliminate 100 million tons of carbon dioxide emissions. Deploying efficient membranes for the purification of hydrogen and natural gas also may accelerate the replacement of coal for electricity generation, while implementing membranes for carbon dioxide separation from flue gas may reduce the cost of carbon capture by 50%.

Despite their great potential, however, the broad adoption of membranes has been hampered by the inadequate separation performance of existing materials. The proposed technology uses molecular filters capable of performing precise separations based on gas molecule size, and enables separations currently unaddressed in industry that may realize the full potential of energy-efficient membrane-based technologies.

This I-Corps project focuses on the development of molecular filters engineered to have similar pore sizes to gas molecules, making them exceptional molecular sieves. Traditional membrane materials consist of single-stranded and flexible polymer chains that pack efficiently in the solid state, leading to virtually no pores in the membranes. This dense packing results in limited productivity because molecules could not diffuse quickly through the dense material.

The materials had low selectivity because they could not distinguish molecules by size. The materials in the proposed design represent a shift in polymer chemistry and materials engineering. A rigid ladder, or double-stranded, molecular motif was incorporate into the polymer chains.

These rigid ladder motifs prevent the dense packing of polymer chains in the solid-state, leading to abundant microporosity that may be leveraged for molecular separations. By systematically tuning the conformation of these ladder motifs, the productivity and selectivity of the membrane may be simultaneously tailored for specific applications. In addition to the potential applications in the energy sector, this project may provide important intellectual insights to guide the understanding and design of porous organic materials with other applications yet to be explored.

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.