Evans’ ACS PRF Award to Aid in Low-Energy, Low-Cost Polymer Membranes

“We’re excited to assist in designing the next generation of low-energy and low-cost membranes,” said Assistant Professor of Materials Science and Engineering Christopher Evans. He has been awarded a $110,000 grant from the American Chemical Society Petroleum Research Fund (ACS PRF) for his research on polymer membranes. The Doctoral New Investigator (DNI) grant supports a two-year project that began in July entitled “Understanding organic liquid transport in polymerized ionic liquid networks and blends.” 

Currently, many industrial separations are performed using distillation which relies on differences in boiling points of components. However, this method requires a large amount of energy and many organic molecules have similar boiling points, making separations difficult. Petroleum is a mixture of thousands of distinct organic molecules and the isolation of the various species represents a multibillion dollar industry.

“Cheap, large scale membranes would enable a number of industries from pharmaceuticals to refineries to move away from distillation, which can account for upwards of 80% of the energy costs for chemical separations,” Evans said. 

The Evans group is focusing on developing polymer membranes which operate under ambient conditions as passive elements. These membranes are being designed to separate components based on their interaction with the polymer. Specifically, the membrane properties can be tuned through synthesis to favor the passage of certain components in a mixture.

To design the next generation of low-energy/low-cost membranes, the Evans group is making polymers with ionic liquid (IL) groups attached to the backbone of the polymer. Ionic liquids are composed entirely of cations and anions which are bulky, molecular species that melt near room temperature. By incorporating ILs into the polymer to create a polymerized ionic liquid (PIL), the polarity and aromaticity can be systematically controlled which dictates the solubility of various organic liquids in the polymer.

“Determining how the molecular scale polymer-liquid interactions relate to the macroscopic membrane performance is a key aim of this work,” Evans said.

Membranes used in separations must also be able to handle pressurized feeds and to that end, the group is pursuing crosslinked network PILs as well as blending of PILs with mechanically robust blend partners. With tougher membranes, the thickness can be decreased to provide a greater permeation of the desired products as long as selectivity is retained.

The DNI grants from the ACS PRF fund the careers of young faculty by supporting fundamental research relevant to the petroleum field and support advanced scientific education of the next generation of scientists and engineers.