This is the monthly networking meeting for faculty affiliated with NDnano. New faculty are welcome! For more information on affiliating with the Center, please contact Heidi Deethardt at deethardt.1@nd.edu.

Presenter: Ruilan Guo, Associate Professor, Chemical and Biomolecular Engineering

Title:

Leveraging Free Volume-based Microporosity Design to Advance Polymer Membrane Separations

Abstract:

Materials-driven, membrane-based separation technologies have great promise to dramatically drive down the energy consumption, carbon footprint, and water intensity of traditional thermally-driven separation technologies, such as cryogenic distillation.  The creation of novel membrane materials with precisely controlled structures and properties holds the key to enabling membrane-mediated solutions to many of the separation-related challenges facing humanity in environment, energy, and sustainability.  Microporous polymers, or high-free-volume polymers, are leading membrane materials for gas separations.  However, existing microporous polymer membranes that follow the size-sieving mechanism suffer from permeability-selectivity tradeoff, physical aging (loss of permeability over time) and membrane plasticization (loss of size sieving capability upon sorption of condensable gases like CO2).  The molecular origin of these materials challenges largely lies in the transient nature of non-equilibrium conformational free volume dictated by polymer chain packing. To address these major challenges, we introduce a new concept of configurational polymer free volume to mimic non-collapsible, permanent microcavities in inorganic molecular sieves, thus enabling physical aging and plasticization resistance in corresponding microporous polymer membranes. This talk will describe several macromolecular strategies that introduce configurational free volume in microporous polymers using iptycene-based structure units. The rich structural hierarchy and chemistry versatility of iptycene units offer great opportunities for generating well-defined yet highly tailorable microstructure and unique supramolecular interactions, which synergistically lead to intriguing membrane properties and attractive gas separation performance. Discussions will emphasize on new macromolecular design concepts and the understanding of fundamental structure-property relationships for these innovative polymer membrane materials.