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Exceptional high gas permeability and physical aging resistance of silyl-functionalized fluorene-based poly(substituted acetylene)s

Year: 2025

Type: article

Abstract: Poly(substituted acetylene)s have emerged as highly promising materials for gas-permeable membranes in gas separation systems. A novel series of silyl-functionalized fluorene-based poly(substituted acetylene)s (Copoly(Flu1-Flu2)s) were synthesized via copolymerization of 1-phenyl-2-(7-trimethylsilyl-9,9-bistrimethylsilylfluoren-2-yl)acetylene (Flu1) with 1-phenyl-2-(7-trimethylsilyl-9,9-dimethylfluoren-2-yl)acetylene (Flu2). Solution-cast copolymer membranes exhibited exceptional gas permeabilities, with the Copoly(Flu1-Flu2)(4:1) membrane showing oxygen (PO2 = 19,800 Barrer) permeability that surpass those of homopolymers. Desilylation via trifluoroacetic acid treatment altered permeability depending on the feed ratio, attributed to competitive effects of chain packing densification and microvoid generation. XRD and N2 adsorption analyses revealed that higher Flu1 content increased chain spacing (d-spacing = 15.2 Å) and BET surface area (492 m2/g), with desilylation inducing pore structure reorganization. The membranes exhibited good thermal stability (Td > 420 °C) and resistance to physical aging (PO2 reduction < 10% within 240 days), underscoring their potential for gas separation applications.

Source: Journal of Membrane Science

DOI: 10.1016/j.memsci.2025.124830

Authors: Yi Lin, Toshikazu Sakaguchi, Tamotsu Hashimoto, Xiaoli Sun, Yanbing Guo, Jiping Chen