PIM hybrids and derivatives: how to make a good thing better

Polymers of intrinsic microporosity (PIMs) are solutionprocessable, rigid, and sterically hindered polymers. Since their inception almost two decades ago, this new class of materials has grown substantially and found prominence in membrane separations. Indeed, the large internal free volume of PIMs has led to the development of highly permeable and moderately selective membranes. However, this modest selectivity often requires further improvements to reach industrial targets for separation performance. Here, we highlight the latest advancements in PIM membrane functionalization to improve the membrane separation performance including the development of molecularly mixed composite matrix membranes, thin film composite carbon molecular sieve membranes, and vapor phase infiltrated membranes.