(11c) Polymer Membranes with Engineered Microporosity for Gas Separations

Amid the growing interest and awareness in clean energy (e.g., hydrogen fuel) and curbing climate change (e.g., carbon capture), membrane-mediated gas separations represent a highly enabling technology for the realization of net zero energy future due to its unprecedented energy efficiency and low carbon footprint. Microporous polymers with precisely controlled free volume-based micrporosity are leading membrane materials for gas separations due to their chemistry versatility that allows for sophisticated manipulation of chemical functionality to construct ideal gas transport pathways. However, existing microporous polymer membranes suffer from permeability-selectivity tradeoff, physical aging and plasticization. the transient nature of non-equilibrium conformational free volume dictated by random polymer chain packing. To address these challenges, we introduce a new concept of configurational polymer free volume to mimic non-collapsible, permanent microcavities presented in inorganic molecular sieves, thus enabling physical aging and plasticization resistance. This talk will describe several macromolecular strategies that introduce configurational free volume in microporous polymers using hierarchical iptycene-based structure units. The introduction of configurational free volume offers great opportunities for generating well-defined yet highly tailorable microporosity and unique supramolecular interactions, synergistically leading to highly attractive gas separation performance surpassing the upper bounds as well as unusual physical aging resistance. Discussions will emphasize on new macromolecular design concepts and the understanding of fundamental structure-property relationships for these innovative polymer membrane materials.