Graft-crosslinked Copolymers Based on Poly(arylene ether ketone)-gc-sulfonated Poly(arylene ether sulfone) for PEMFC Applications a Xuan Zhang, Zhaoxia Hu, Linqiang Luo, Shanshan Chen, Jianmei Liu, Shouwen Chen,* Lianjun Wang* Introduction Over the past decades, the international community has pushed ahead with a nationwide campaign to build a resource conserving and environment friendly society. Against this background, polymer electrolyte membrane fuel cell (PEMFC) technology has become a popular research area as a promising energy resource. The proton exchange membrane (PEM), which serves as a proton transfer carrier and fuel barrier, is one of the limiting factors in the large scale application of PEMFC technology. The current Communication X. Zhang, Z. Hu, S. Chen, J. Liu, S. Chen, L. Wang School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China Fax: þ86 25 84315518; E-mail: shouwenchen@yahoo.com.cn, wanglj@mail.njust.edu.cn L. Luo National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China a Supporting Information for this article is available from the Wiley Online Library or from the author. Novel poly(arylene ether ketone) polymers with fluorophenyl pendants and phenoxide-termi- nated wholly sulfonated poly(arylene ether sulfone) oligomers are prepared via Ni(0)-catalyzed and nucleophilic polymerization, respectively, and subsequently used as starting materials to obtain graft-crosslinked membranes as polymer electrolyte membranes. The phenoxide-termi- nated sulfonated moieties are introduced as hydrophilic parts as well as crosslinking units. The chemical structure and morphology of the obtained membranes are confirmed by 1 H NMR and tapping-mode AFM. The properties required for fuel cell applications, including water uptake and dimensional change, as well as proton conductivity, are investigated. AFM results show a clear nanoscale phase-separation microstructure of the obtained membranes. The membranes show good dimensional stability and reasonably high proton conductivities under 30–90% relative humidity. The anisotropic proton conduc- tivity ratios (s ?/jj ) of the membranes in water are in the range 0.65–0.92, and increase with an increase in hydrophilic block length. The results indicate that the graft-crosslinked membranes are promis- ing candidates for applications as poly- mer electrolyte membranes. 1108 Macromol. Rapid Commun. 2011, 32, 1108–1113 ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com DOI: 10.1002/marc.201100116