Molecularly Designed Stabilized Asymmetric Hollow Fiber Membranes for Aggressive Natural Gas Separation

New rigid polyimides with bulky CF₃ groups were synthesized and engineered into high-performance hollow fiber membranes. The enhanced rotational barrier provided by properly positioned CF₃ side groups prohibited fiber transition layer collapse during cross-linking, thereby greatly improving CO₂ /CH₄ separation performance compared to conventional materials for aggressive natural gas feeds.