Polymers of Intrinsic Microporosity (PIMs)

Based on cumulative research from the past two decades, this personal perspective defines the structurally unique features of Polymers of Intrinsic Microporosity (PIMs), which result in a distinct combination of properties, including solution-processability and microporosity, providing organic materials suitable for the fabrication of membranes that perform efficient molecular sieving. [Display omitted] •Personal reflection on the development of Polymers of Intrinsic Microporosity (PIMs).•Explanation of why PIMs form a distinct class of polymer and microporous material.•Re-definition of PIMs based on their method of synthesis, structure and properties.•Rigidity and sub-nanometre pore size combine to make PIM membranes selective.•Free volume is largely interconnected but only for the transport of small gases.