Room-temperature ionic liquids (RTILs) are organic salts which are liquids at room temperature. They have little or no vapor pressure, are non-flammable and thermally stable at and above 300 °C. Current applications of RTILs include “green solvents” for chemical reactions, ion conduction and storage and separation of CO2. Imidazolium-based RTILs are particularly interesting because they can be easily tailored to create task-specific organic materials.

Our research groups have utilized this versatile chemistry to create novel imidazolium-based RTILs and crosslinked polymers for use in gas separation applications. Using RTILs containing two tethered cationic units, we are exploring the effects of cation spacer length and chemistry on gas solubility and selectivity. We have also synthesized analogous cross-linked polymers based on these new RTILs. We are examining the permeability, solubility and diffusion properties of these materials. Our current focus is determining the effects of molecular structure, chemistry, and inclusion of liquid RTIL content in crosslinked networks on gas separation performance.

The synthesis, characterization, and gas separation performance of these novel RTIL-based materials in CO2/N2 and CO2/CH4 separation applications will be discussed.