Asymmetric membranes by wet phase inversion of phenylated polyphenylene

Asymmetric membranes of phenylated polyphenylene were prepared by wet phase inversion. The polyphenylene ( M n = 62 kDa, PD = 2.3) was prepared by Diels–Alder polymerization of 1,4‐bis(tetraphenylcyclopentadienonyl)benzene with 1,4‐diethynylbenzene at 180°C. Solvents and non‐solvents were experimentally identified and solvent : non‐solvent systems were evaluated by the quality of the resulting membranes. Cyclohexanone/ n‐ butanol (88 : 12) as solvent and n‐ butanol as the non‐solvent were found to afford the best asymmetric membranes with minimal defects. Membranes (20–30 µm thick) from coagulating 11.5 wt % polyphenylene from cyclohexanone/ n ‐butanol in n ‐butanol baths exhibited 250–300 nm, non‐porous skins overlaying 20–30 µm of open‐celled, spongiform structure. Due to a relatively high glass transition temperature of 370°C, the phenylated polyphenylene membranes retained their porosity to 200°C higher than polysulfone asymmetric membranes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013