No abstract

A vinylpyridine block copolymer was prepared by stepwise controlled/living radical polymerization with a novel bifunctional initiator, 4‐(2‐bromopropanoyloxy)‐N‐(p‐methylbenzyloxy)‐2,2,6,6‐tetramethylpiperidine. The initiator was synthesized in a facile manner using commercially available p‐xylene and 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (4‐hydroxy TEMPO). Through stepwise atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and nitroxide‐mediated radical polymerization (NMRP) of 4‐vinylpyridine (4VP), the PMMA‐b‐P4VP copolymer was prepared with a wide range of the copolymer compositions. Microphase‐separation was demonstrated in cross sectional TEM images of self‐standing block copolymer membranes.

A multiply‐fluorinated cobalt phthalocyanine (CoFPC) was prepared, which could reversibly interact with oxygen. CoFPC was introduced into the hydrophobic perfluoroethylene‐backbone domain of the Nafion membrane. The localization of CoFPC did not reduce the high proton conductivity (10−2–10−3 S cm−1) ascribed to the hydrophilic channel of Nafion. The oxygen permeability through the CoFPC/Nafion membrane was higher than the nitrogen permeability and that of the pristine Nafion membrane, and was significantly enhanced at the lower upstream pressure. The permselectivity of oxygen versus nitrogen increased beyond 20 with the CoFPC content in the membrane. The CoFPC/Nafion membrane was coated on a glassy carbon modified with a Pt/C catalyst. The high electrochemical reduction current of oxygen suggested that the CoFPC/Nafion membrane efficiently supplied oxygen to the Pt/C catalyst. Copyright © 2009 John Wiley & Sons, Ltd.