3,3'-Di(4″-methyl-phenyl)-4,4'-difluorodiphenyl sulfone (DMPDFPS), a new monomer with two pendent benzyl groups, was easily prepared by Suzuki coupling reaction in high yield. A series of side-chain type ionomers (PAES-Qs) containing pendant side-chain benzyltrimethylammonium groups, which linked to the backbone by alkaline resisting conjugated C-C bonds, were synthesized via polycondensation, bromination, followed by quaternization and alkalization. To assess the influence of side-chain and main-chain aromatic benzyltrimethylammonium on anion exchange membranes (AEMs), the main-chain type ionomers (MPAES-Qs) with the same backbone were synthesized following the similar procedure. GPC and (1)H NMR results indicate that the bromination shows no reaction selectivity of polymer configurations and ionizations of the side-chain type polymers display higher conversions than that of the main-chain type ones do. These two kinds of AEMs were evaluated in terms of ion exchange capacity (IEC), water uptake, swelling ratio, λ, volumetric ion exchange capacity (IECVwet), hydroxide conductivity, mechanical and thermal properties, and chemical stability, respectively. The side-chain type structure endows AEMs with lower water uptake, swelling ratio and λ, higher IECVwet, much higher hydroxide conductivity, more robust dimensional stability, mechanical and thermal properties, and higher stability in hot alkaline solution. The side-chain type cationic groups containing molecular configurations have the distinction of being practical AEMs and membrane electrode assemblies of AEMFCs.

A series of cross-linked multiblock copoly(arylene ether sulfone) ionomer/nano-ZrO 2 (CLQCPAES/nanoZrO 2 ) composite anion exchange membranes were prepared via block copolymerization, bromomethylation, ultrasonication blending, self-crosslinking, quaternization and alkalization. The structure, and the surface and cross section morphology of the CLQCPAES/nano-ZrO 2 composite membranes were characterized by solubility tests, FT-IR, XRD and SEM analyses. The combination of the determined results revealed that the CLQCPAES/nano-ZrO 2 composite membranes are a complex cross-linking networks of hydrophobic domains/hydrophilic domains/nano-ZrO 2 with a clear zonal distribution of uniform nano-sized particles in the hydrophilic domains, when the nano-filler loading was below 7.5%. Basic performances of the CLQCPAES/nano-ZrO 2 composite membranes were assessed to investigate their application in fuel cells in terms of the water uptake, swelling ratio, ion exchange capacity (IEC), hydroxide conductivity, thermal and mechanical properties, and alkaline stability. The modification of anion exchange membranes with multiblock ionomer structures, the use of a crosslinking technique and the introduction of nano-ZrO 2 particles greatly enhanced the water uptake, hydroxide conductivity, mechanical properties and alkaline stability of the composite membranes. In particular, the CLQCPAES/7.5%ZrO 2 membrane with an IEC value of 1.23 mmol g À1 exhibited the best comprehensive properties and constitutes a good potential candidate for an anion exchange membrane to be used in AEMFCs.