In-situ generation of polymer molecular sieves in polymer membranes for highly selective gas separation

Molecular sieve materials (MSMs) are regarded as ideal fillers for the fabrication of mixed matrix membranes (MMMs). However, the preparation of MSMs-based MMMs usually involves physical mixing of insoluble filler and polymer matrix, which inevitably leads to filler agglomeration and two-phase incompatibility especially for high filler loading. Herein, we report a new strategy to construct MMMs through generating polymer molecular sieve (PMS) fillers in-situ in a thermally stable polymer matrix by post heating treatment. The in-situ generated PMS-based MMMs (i-PMS MMMs) possess greatly improved interfacial compatibility between matrix and filler and the effective loading content of PMS filler can reach as high as 70 wt%. The molecular sieving property of PMS endows the i-PMS MMMs with high gas selectivity of 183.0 for H2/CH4 and 128.9 for H2/N2, approaching or exceeding the state-of-the-art 2015 upper bound.