Molecular Mobility of the High Performance Membrane Polymer PIM-1 as Investigated by Dielectric Spectroscopy

The increasing demand for energy efficient separation processes fosters the development of new high performance polymers as selective separation layers for membranes. PIM-1 is the archetypal representative of the class of polymers of intrinsic microporosity (PIM) which are considered most promising in this sector, especially for gas separations. Since their introduction, PIMs stimulated a vast amount of research in this field and meanwhile evolved to the state-of-the-art in membrane technology for gas separation. The major obstacle for extending the practical membrane application is their strong tendency to physical aging. For the first time, investigations by broadband dielectric spectroscopy (BDS) addressing molecular dynamics and conductivity in PIM-1 are presented. As chain packing during film formation from the casting solution and physical aging are key factors determining the separation performance of PIMs as membrane materials, characterization of the molecular mobility in such materials as revealed by BDS will provide valuable information for further development and optimization.