Fluorine-Based Acetylene Copolymer Membranes with Enhanced Gas Permeability and Aging Resistance

: With the growing demand for high-performance membranes in advanced gas separation applications, developing materials with both superior gas permeability and excellent long-term stability remain a critical challenge. Fluorine-based acetylene copolymers ( Poly(FSDPA- co -SDPA) s) with varying molar feed ratios were synthesized via TaCl 5 – n -Bu 4 Sn-catalyzed copolymerization. The corresponding membranes were fabricated by solution casting and subsequently desilylated to obtain DSpoly(FSDPA- co -SDPA) membranes. Comprehensive characterization revealed that desilylation reaction effectively removed trimethylsilyl groups from Poly(FSDPA- co -SDPA) membranes, leading to enhanced thermal stability, complete insolubility in organic solvents, and a refined microporous structure with significantly increased BET surface area (up to 520 m 2 /g) and total pore volume. Gas permeability measurements revealed significant enhancements, with DSpoly(FSDPA- co -SDPA)(4:1) achieving an O 2 permeability of 14,000 Barrer, which is approximately 2.5 times higher than that of its silylated counterpart. Moreover, the desilylated membranes exhibited excellent resistance to physical aging, retaining up to 85.0% of their initial O 2 permeability after 360 days. This study highlights that copolymerization combined with desilylation is a powerful strategy for tailoring the microstructure of fluorine-based acetylene copolymer membranes, resulting in an optimal balance of high gas permeability and long-term stability for advanced gas separation applications.