Journal of Power Sources 196 (2011) 8272–8279 Contents lists available at ScienceDirect Journal of Power Sources jou rnal h omepa g e: www.elsevier.com/locate/jpowsour Anionic membrane and ionomer based on poly(2,6-dimethyl-1,4-phenylene oxide) for alkaline membrane fuel cells Ai Lien Ong a,b , Saeed Saad b , Rong Lan a,b , Robert J. Goodfellow c , Shanwen Tao a,b,∗ a Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ, UK b Department of Chemistry, Heriot Watt University, Edinburgh EH14 4AS, UK c Technology and Research Services, Heriot Watt University, Edinburgh EH14 4AS, UK a r t i c l e i n f o Article history: Received 12 March 2011 Received in revised form 25 May 2011 Accepted 3 June 2011 Available online 13 June 2011 Keywords: Alkaline membrane fuel cell Amination Bromination Ionic conductivity PPO a b s t r a c t Hydroxyl-ion conductive poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) membranes with different char- acteristics were prepared via relatively simple bromination/amination serial reactions with reduced number of involved chemicals and shorter reaction time. The effects of reactants ratio, reaction atmosphere, polymer concentration, casting solvent, and hydroxylation treatment on reaction were investigated in details. The microstructure, water uptake, swelling ratio, ion-exchange capacity and ionic conductivity of the membranes were also studied. The obtained results demonstrate that, the ionic con- ductivity of the membrane is dependent on casting solvent. The N-methyl-2-pyrrolidonecast membrane exhibits the highest conductivity with the thinnest film. Although the membrane was prepared via a relatively simple preparation route with least toxic chemicals, a competitive ionic conductivity value of 1.64 × 10 -2 S cm -1 was achieved at 60 ◦ C. A power density of 19.5 mW cm -2 has been demonstrated from the alkaline membrane fuel cell operated at 70 ◦ C, assembled from the entirely homemade membrane electrode assembly without any hot-pressing. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Alkaline membrane fuel cells (AMFCs) have recently attracts attention of many researchers worldwide [1–11]. A boost in the research regarding AMFCs is due to the development of alkaline anion-exchange membranes (AEM), which have highly potential in eliminating the problem of the progressive carbonation of alka- line electrolyte [12], and also as an alternative approach to the challenges in Nafion-based proton exchange membrane fuel cells (PEMFCs) [13–15], such as high cost membranes [16] and platinum- based catalyst [17]. Analogous to PEMFCs [18,19], a continuous development of AEM for AMFC technology is therefore apparently essential. Postpolymerization modification is an important method for obtaining new chemical and physical properties for an exist- ing polymer to be tailored for specific applications [20]. A series of methods for preparing diverse AEM have been devel- oped for AMFC applications, ranging from radiation–grafting [21], halogenation–quaternization reactions [22] to quaternization–sol gel reactions [23]. The most commonly utilized method for ∗ Corresponding author at: Department of Chemical and Process Engineering, Uni- versity of Strathclyde, Glasgow G1 1XJ, UK. Tel.: +44 (0)1415482361; fax: +44 (0)1415482539. E-mail address: shanwen.tao@strath.ac.uk (S. W. Tao). synthesizing strongly basic AEM is halogenation–quaternization reactions, usually comprising chloromethylation and quaternary amination. With the increasing use of toxic chemicals in industry, simple and rapid methods for membranes preparation with least toxic materials are becoming more and more important. Although the use of chloromethylmethyl ether in chloromethy- lation provides excellent conversions and high yields, however this material is a carcinogen and rather expensive [24]. In addition, to improve mechanical stability, the membranes will suffer cross-linking and resulting in limitation of membrane molding with intricate shape [25]. In order to avoid the use of carcinogen materials, Wu and co-workers have developed a new series of AEMs directly from engineering polymer, poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) through sequence processes of bromination–hydroxylation–quaternization–sol–gel reaction–heat treatment [26]. In their works, molar ratio of bromine to PPO of 1.5:1 was used for bromination; hydroxyla- tion treatment was employed; quaternization step was conducted for 13 h in a medium, comprising triethylamine, chlorobenzene, dimethylformamide and ethanol; additional used of monophenyl- triethoxysilane and tetraethoxysilane for 24 h sol–gel reaction was involved; and the synthesis route was ended with heat treatment at 130 ◦ C for 5 h. To further simplify the membranes preparation procedure with least toxic materials, PPO-based AEMs were prepared via a 0378-7753/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2011.06.015