Sulfonated fluorinated poly aryl ether

Scheme 2.31 Structure of sulfonated fluorinated poly(aryl ether ketone) with cross-linking alkyne moiety. Taken from Ref. [145],...

Jeong et al. [147] synthesized a sulfonated fluorinated poly(aryl ether ketone) with pendant phenyl rings, as shown in Scheme 2.32. Both proton conductivity and WU increased with an increase in temperature. For example, the proton conductivity of a polymer membrane with DS=0.96 was 83mS/cm at 25 °C and 98mS/cm at 80 °C, comparable to that of Nafion 117 (proton conductivity=45 mS/cm at 25 °C and 96 mS/cm at 80 °C). The pendant phenyl ring containing sulfonic acid group improved WU from... 

J. Ding, Y. Qi, M. Day, J. Jiang, and C. L. Callender. A low temperature polycondensation for the preparation of highly fluorinated poly(aryl-ene ether sulfone)s containing crosslinkable pentafluorostyrene moieties. Macromol. Chem. Phys., 206 2396-2407, 2005. 

The acid-base Nafion composite membranes include blends of Nafion with polypyrrole (PPy) [98-104], polybenzimidazole (PBI) [105-107], poly (propyleneoxide) (PPO) [108, 109], polyfurfuryl alcohol (PFA) [110], poly(vinyl alcohol) (PVA) [111-115], sulfonated phenol-formaldehyde (sPF) [116], polyvinylidene fluoride (PVdF) [117-122], poly(p-phenylene vinylene) (PPV) [123], poly(vinyl pyrrolidone) (PVP) [124] polyanifine (PANI) [125-128], polyethylene (PE) [129], poly(ethylene-terephtalate) [130], sulfated p-cyclodextrin (sCD) [131], sulfonated poly(ether ether ketone) (sPEEK) [132-135], sulfonated poly(aryl ether ketone) (sPAEK) [136], poly(arylene ether sulfone) (PAES) [137], poly(vinylimidazole) (PVl) [138], poly(vinyl pyridine) (PVPy) [139], poly (tetrafluoroethylene) (PTFE) [140-142], poly(fluorinated ethylene-propylene) [143], sulfonated polyhedral oligomeric silsesquioxane (sPOSS) [144], poly (3,4-ethylenedioxythiophene) (PEDT) [145, 146], polyrotaxanes (PR) [147], purple membrane [148], sulfonated polystyrene (PSSA) [149, 150], polystyrene-b-poly(ethylene-ran-butylene)-bpolystyrene (SEES) [151], poly(2-acrylamido-2-methyl-l-propanesulphonic acid-co-l,6-hexanediol propoxylate diacrylate-co-ethyl methacrylate) (AMPS) [152], and chitosan [31]. A binary PVA/chitosan [153] and a ternary Nafion composite with PVA, polyimide (PI) and 8-trimethoxy silylpropyl glycerin ether-1,3,6-pyrenetrisulfonic acid (TSPS) has also been reported [154]. 

Scheme 2.34 Structure of highly fluorinated sulfonated poly(aryl ether). Taken from Ref. [150],...

Zhang et al. [151] used Ni(0)-catalyzed coupling copolymerization to synthesize a series of sulfonated fluorinated poly(p-phenylene-co-aryl ether ketone)s (SPP-co-PAEKs). Copolymerization with the sulfonated monomer 2,5-dichloro-3 -sulfobenzophenone (DCSB) and 2,2 - w[4-(4-chlorobenzoyl)]phenoxyl perfluoropropane (BCPPF) was carried out by varying the molar ratio of DCSBrBCPPF. The structure of SPP-co-PAEKs is shown in Scheme 2.35. 

B. Liu, G.P. Robertson, M.D. Guiver, Y.M. Sun, Y.L. Liu, J.Y. Lai, S.D. Mikhailenko, S. Kaliaguine, Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials, J. Polym. Sci. Part B Polymer Physics 44 (16) (2006)2299-2310. 

Sulfonated poly(aryl ether ketone)s appear to have their merits especially in DMFC, where one of the problems of current commercially available per-fluorinated membranes is the relatively high methanol permeability, which translates to a reduced power efficiency of the fuel cell. 

Even higher conductivities were found for block copolymers consisting of sulfonated poly(aryl ether sulfone) blocks alternating with fluorinated aromatic polyether blocks (Fig. 13), although they had relatively high water uptake even at room temperature. Table 4 shows conductivites and water uptake data. 

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