Abstract
Intrinsic microporosity is one of the most important properties of high free volume polymers. If one arranges all known polymers by increasing free volume in a continuous line, at the endpoint, merely a very few polymers with extremely high free volume of above 20% can be named. Today, only some polyacetylenes (best known polytrimethylsilylpropyne (PTMSP)), Teflon copolymers (Teflon® AF-types, Hyflon® AD), one silylated polynorbornene and PIM polymers are identified. PIM polymers, known since 2004 [1], are ladder type polycondensates composed of flat dioxane rings and sites of contortion. Their exceptional basic properties as membrane separation materials have been recovered recently [2].
