Highly fluorinated, hyperbranched polymers were synthesized from the polycondensation of AB 2 monomers, 3,5-bis[(pentafluorobenzyl)oxy]benzyl alcohol and 3,5-bis[(pentafluorobenzyl)-oxy]phenol with potassium carbonate base, and 18-crown-6 phase transfer agent in a variety of polar aprotic solvents. The regioselectivity of the polymerization was optimized and was found to be temperature dependent. The new polymerization technique produced higher molecular weight polymer using safer conditions than earlier methods. The resulting optimization was used to control substitution of oxygen-bearing nucleophiles along nonactivated fluoroaryl systems in high yield. Water was found to induce side reactions that generate a highly conjugated fluoroaryl phenol with lowered reactivity. The removal of a methylene spacer in the polymer backbone of the hyperbranched polymer produced a polymer with greater thermal stability. The reaction conditions for polymerization were found to be general for nucleophilebearing perfluorinated systems. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52,[985][986][987][988][989][990][991][992][993][994]

Highly branched perfluorinated aromatic polyether copolymers were prepared from the polycondensation of the AB2 monomer, 3,5‐bis[(pentafluorobenzyl)oxy]benzyl alcohol with a variety of fluoroaryl and alkyl bromide AB comonomers. The structures and comonomer distribution of the resulting polymers were characterized in detail. 1H NMR data from kinetic trials illustrated that perfluoroaryl AB comonomer distribution correlated to AB comonomer sterics. 19F NMR data revealed that fluorinated AB monomers and 3‐bromo‐1‐propanol AB monomers were distributed within the AB2 polymer backbone, while longer alkyl bromide AB monomers, 6‐bromo‐1‐hexanol, were mostly distributed along hyperbranched polymer chain ends. In general, as AB comonomer incorporation increased for nonsterically hindered copolymers, thermal decomposition onset increased and glass transition temperatures decreased. The combined data demonstrated the effect of comonomer distribution and sterics on physical properties of AB2‐based polymer systems. The resulting materials were used to cast thin polymer films for measurement of contact angle, which were shown to be directly related to comonomer content. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1880–1894

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In this research, membrane formation with hyperbranched perfluorinated polymers (HBFP) was investigated. To create a tough membrane, HBFP was blended and crosslinked with a tougher linear polymer. Blending only or crosslinking only was not sufficient to create a tough membrane, but combining blending with crosslinking was successful. Miscibility, phase separation, and thermal and mechanical properties were evaluated for a variety of systems. By using a toughening linear polymer with lower polarity, reduced phase separation and improved mechanical properties were seen. Overall, imidazolecontaining HBFPs produced the clearest and toughest blends. These new hyperbranched ionomers and copolymers are strong candidates for future use in anhydrous proton exchange membranes.Additional supporting information may be found in the online version of this article.

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