Polymers of intrinsic microporosity (PIMs), as novel microporous organic polymers polymerized by rigid monomers that have sites of contortion, have great application potential in homogeneous catalysis and hydrogen storage due to their high specific surface, chemical and physical stability and pore size controllability. Particularly, PIMs composed of polymer chains attract more attention in gas separation membranes due to their superior gas separation properties and good solubility. Here, the classification and applications of PIMs as well as the properties including stability, gas permeability and gas selectivity of PIMs gas membrane are introduced. The structure controls and modifications of PIMs gas membrane and the relationship between molecular structures and gas separation properties are described in detail. Finally, the problems existed in the present research are pointed out and a brief comment on the development is given.

Contents
1 Introduction
2 Summary of PIMs gas separation membranes
2.1 Classification of PIMs
2.2 Properties of PIMs gas separation membranes
3 Structure controls of PIMs gas separation membranes
3.1 Change of the rigidity of linking groups between benzene rings
3.2 Adjustment of the angles of spiro or twist centers and the lengths between the spirocentres
3.3 Introduce of different pendant substituents
4 Modifications of PIMs gas separation membranes
4.1 Cross-linking
4.2 Blending
5 Conclusions and outlook