(587g) Design of Robust, High-Performance Ionenes and Ionic Composites for Membrane-Based Gas Separations

We have developed a collection of high-performance (HP) ionenes, or polymers which contain ionic groups along the backbone rather than as pendants. These materials combine structural elements typically associated with state-of-the-art gas-separation membranes with functionality utilized in ultra-high-performance engineering polymers (i.e. imide, amide, urea linkages). This work probes the effects of spacing and sequencing functional features and ionic moieties within these ionenes, which contain imidazolium cations (paired with fluorinated anions) integrated within the main chain. Structural segments known to impart free volume, including spirobisindane and Tröger’s base units, have also been incorporated within these ionenes. These materials are robust, exhibiting good thermal and mechanical stability, and are extremely tailorable due to the design and modular synthetic method. Thus, the thermophysical properties and transport behaviors of these materials are highly tunable based on methodical combination of diverse monomers and linkages. These polymeric materials exhibit additional self-assembly and nanostructuring when impregnated with “free” imidazolium-based ionic liquids (IL) or more complex ionic fillers, which imparts another degree of tunability and coordinates the ionene chains. These HP-ionenes are thoroughly characterized in order to develop structure-property relationships which correlate functional and charged features with the resultant polymer properties. Composites are similarly analyzed for comparison with the corresponding neat polymers, to gain a better understanding of the coordination between polymer chains and dispersed additives. This presentation highlights the design and synthesis of these HP-ionenes, focusing on the performance of these materials as gas separation membranes.