Investigation of sulfonated poly(ether ether ketone sulfone)/heteropolyacid composite membranes for high temperature fuel cell applications

The sulfonated poly(ether ether ketone sulfone) (SPEEKS)/heteropolyacid (HPA) composite membranes with different HPA content in SPEEKS copolymers matrix with different degree of sulfonation (DS) were investigated for high temperature proton exchange membrane fuel cells. Composite membranes were characterized by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR band shifts suggested that the sulfonic acid groups on the copolymer backbone strongly interact with HPA particles. SEM pictures showed that the HPA particles were uniformly distributed throughout the SPEEKS membranes matrix and particle sizes decreased with the increment of copolymers' DS. The holes were not found in SPEEKS‐4/HPA30 (consisting of 70% SPEEKS copolymers with DS = 0.8 and 30% HPA) composite membrane after composite membranes were treated with boiling water for 24 h. Thermal stabilities of the composite membranes were better than those of pure sulfonated copolymers membranes. Although the composite membranes possessed lower water uptake, it exhibited higher proton conductivity for SPEEKS‐4/HPA30 especially at high temperature (above 100 °C). Its proton conductivity linearly increased from 0.068 S/cm at 25 °C to 0.095 S/cm at 120 °C, which was higher than 0.06 S/cm of Nafion 117. In contrast, proton conductivity of pure SPEEKS‐4 membrane only increased from 0.062 S/cm at 25 °C to 0.078 S/cm at 80 °C. At 120 °C, proton conductivity decreased to poor 0.073 S/cm. The result indicated that composite membranes exhibited high proton conductivity at high temperature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1967–1978, 2006     

磷酸掺杂的聚苯并咪唑复合膜在高温质子交换膜燃料电池中的应用

磷酸掺杂的聚苯并咪唑复合膜在高温质子交换膜燃料电池中的应用     

Comparison of Electrochemical Synthesis of Ammonia by Using Sulfonated Polysulfone and Nafion Membrane with Sm1.5Sr0.5NiO4

Polysulfone (PSF) and sulfonated polysulfone (SPSF) were synthesized and characterized by IR spectrum. Sm_1.5Sr_0.5NiO₄ (SSN) and Ni‐Ce_0.8Sm_0.2O_2?δ (Ni‐SDC, Ni‐samarium doped ceria) were prepared and characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was synthesized from wet hydrogen and dry nitrogen with applied voltage, using SSN as cathode, Ni‐SDC as anode, Nafion and SPSF as proton membrane respectively. The performances of Nafion and SPSF membranes in ammonia synthesis were investigated and compared at atmospheric pressure and low temperature (25–100°C). The results demonstrated that the proton conducting performances of Nafion and SPSF membranes were similar and the highest rates of evolution of ammonia were up to 1.05×10^?8 and 1.03×10^?8 mol·cm^?2·s^?1 respectively at 80°C and 2.5 V.     

Preparation and characterization of sulfonated poly(phenylene oxide) proton exchange composite membrane doped with phosphosilicate gels

A new class of proton exchange composite membranes made by incorporating phosphosilicate gels into SPPO matrix was prepared and characterized. The thermal stability was evaluated by TGA and DSC, and the amorphous structure information was provided from XRD. The experimental results showed that the composite membranes have good stability to oxidation by Fenton's reagent test, and the membrane dimension is hardly changed, even at high temperature. The hydration number values of the persulfonic acid group of composite membranes were lower than that of Nafion 112 at room temperature, but the water uptake of composite membranes at 80°C was higher than that of Nafion 112. With increasing relative humidity and doping amount, the conductivity of the composite membranes increased. Moreover, the conductivities of water-equilibrated composite membranes were higher than that of Nafion 112 (0.0871 S/cm) at room temperature, and the highest conductivity for the composite membrane was 0.216 S/cm. Copyright © 2007 John Wiley & Sons, Ltd.     

Effect of acidification treatment and morphological stability of sulfonated poly(arylene ether sulfone) copolymer proton‐exchange membranes for fuel‐cell use above 100 °C

Directly copolymerized wholly aromatic sulfonated poly(arylene ether sulfone) copolymers derived from 4,4′‐biphenol, 4,4′‐dichlorodiphenyl sulfone, 3,3′‐disulfonated, and 4,4′‐dichlorodiphenyl sulfone (BPSH) were evaluated as proton‐exchange membranes for elevated temperature operation (100–140 °C). Acidification of the copolymer from the sulfonated form after the nucleophilic step (condensation) copolymerization involved either immersing the solvent‐cast membrane in sulfuric acid at 30 °C for 24 h and washing with water at 30 °C for 24 h (method 1) or immersion in sulfuric acid at 100 °C for 2 h followed by similar water treatment at 100 °C for 2 h (method 2). The fully hydrated BPSH membranes treated by method 2 exhibited higher proton conductivity, greater water absorption, and less temperature dependence on proton conductivity as compared with the membranes acidified at 30 °C. In contrast, the conductivity and water absorption of a control perfluorosulfonic acid copolymer (Nafion 1135) were invariant with treatment temperature; however, the conductivity of the Nafion membranes at elevated temperature was strongly dependent on heating rate or temperature. Tapping‐mode atomic force microscope results demonstrated that all of the membranes exposed to high‐temperature conditions underwent an irreversible change of the ionic domain microstructure, the extent of which depended on the concentration of sulfonic acid sites in the BPSH system. The effect of aging membranes based on BPSH and Nafion at elevated temperature on proton conductivity is also discussed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2816–2828, 2003     

含氨基聚芳醚酮/磺化聚芳醚酮砜中高温质子交换复合膜的制备与性能研究

以自制的高磺化度磺化聚芳醚酮砜(SPAEKS)和含有氨基的聚芳醚酮(Am-PAEK)为原料,通过共溶剂涂膜法制备了不同重量比例的Am-PAEK/SPAEKS复合膜.通过高温(160℃)处理使氨基和磺酸基团在复合膜内形成交联,制得交联型复合膜.复合膜的热性能、尺寸稳定性、阻醇性能有所提高,而且交联型复合膜中的Am-PAEK/SPAEKS-C-3质子传导率在120℃时达到了0.0892 S/cm,高于在相同测试条件下SPAEKS膜的0.0654 S/cm和Nafion膜的0.062 S/cm,而其甲醇渗透系数在25℃时达到0.14×10-6cm2/s,低于SPAEKS膜的0.85×10-6cm2/s和Nafion膜的2×10-6cm2/s.实验结果表明,Am-PAEK/SPAEKS交联型复合膜有望在中高温质子交换膜燃料电池中得到应用.     

Sulfonated poly(aryl ether ketone)s containing naphthalene moieties obtained by direct copolymerization as novel polymers for proton exchange membranes

A series of sulfonated poly(aryl ether ketone)s (SPAEKs) were prepared by aromatic nucleophilic polycondensation of 2,6‐dihydroxynaphthalene with 5,5′‐carbonyl‐bis(2‐fluorobenzenesulfonate) and 4,4′‐difluorobenzophenone. The structure and degree of sulfonation (DS) of the SPAEKs were characterized using ¹H NMR spectroscopy. The experimentally observed DS values were close to the expected values derived from the starting material ratios. The thermal stabilities of the SPAEKs were characterized by thermogravimetric analysis, which showed that in acid and sodium salt forms they were thermally stable in air up to about 240 and 380 °C, respectively. Transparent membranes cast from the directly polymerized SPAEKs exhibited good mechanical properties in both dry and hydrated states. The dependence of water uptake and of membrane swelling on the DS at different temperatures was studied. SPAEK membranes with a DS from 0.72 to 1.60 maintained adequate mechanical properties after immersion in water at 80 °C for 24 h. The proton conductivity of SPAEK membranes with different degrees of sulfonation was measured as a function of temperature. The proton conductivity of the SPAEK films increased with increased DS, and the highest room temperature conductivity (4.2 × 10^?2 S/cm) was recorded for a SPAEK membrane with a DS of 1.60, which further increased to 1.1 × 10^?1 S/cm at 80 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2866–2876, 2004     

Composite polymer electrolyte membranes comprising triblock copolymer and heteropolyacid for fuel cell applications

Hybrid organic/inorganic composite polymer electrolyte membranes consisting of a triblock copolymer (tBC) and varying concentrations of heteropolyacid (HPA) were investigated for application in proton exchange membrane fuel cells (PEMFC). An ABC triblock copolymer, that is, polystyrene‐b‐poly(hydroxyethyl acrylate)‐b‐poly (styrene sulfonic acid), PS‐b‐PHEA‐b‐PSSA, at 28:21:51 wt % was synthesized via atom transfer radical polymerization (ATRP) and solution‐blended with a commercial HPA. Upon the incorporation of HPA into the tBC, the symmetric stretching bands of both the SO group (1187 cm^?1) and the ? OH group (3440 cm^?1) shifted to lower wavenumbers (1158 and 3370 cm^?1). The shift in these FTIR absorptions suggest that the HPA particles strongly interact with both the sulfonic acid groups in the PSSA domains and the hydroxyl groups in the PHEA domains. When the weight fraction of HPA was increased to 0.2, the room‐temperature proton conductivity of the composite membrane increased from 0.048 to 0.065 S/cm, presumably because of the intrinsic conductivity of the HPA particles and the enhanced acidity of the sulfonic acid in the tBC. The water uptake of the composite membranes decreased from 130 to 48% with an increase of the HPA weight fraction to 0.4. The decrease in water uptake is likely a result of the decrease in the number of available water absorption sites because of the hydrogen bonding interaction between the HPA particles and the tBC matrix. Scanning electron microscopy and transmission electron microscopy images showed that the HPA nanoparticles with a diameter of 200–300 nm were uniformly distributed throughout the tBC matrix up to an HPA weight fraction of 0.4. Thermal stability of the composite membranes (decomposition temperature > 400 °C) was enhanced as compared with the pristine tBC membrane, presumably because of the strong specific interaction of the HPA particles with the sulfonic acid and hydroxyl groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 691–701, 2008     

Proton‐conductive membranes based on blends of polyimides

We prepared novel proton‐conductivity membranes based on blends of sulfonated polyimides. The blend membranes were prepared from a sulfonated homopolyimide and a sulfonated copolyimide with a solvent‐casting method. The proton conductivities of the blend membranes were measured as functions of the temperature with four‐point‐probe electrochemical impedance spectroscopy. The conductivity of the membranes strongly depended on the sulfonated homopolyimide content and increased with an increase in the content. The proton conductivity of all the blended membranes indicated a higher value than that determined in Nafion at 80 °C, and this may mean that the proton transfer in the blend membranes is responsible for the ionic channels induced by the hydrophobic and hydrophilic domains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1325–1332, 2007     

Highly sulfonated multiblock copoly(ether sulfone)s for fuel cell membranes

Highly sulfonated multiblock copoly(ether sulfone)s applicable to proton electrolyte fuel cells (PEFCs) were synthesized by the coupling reaction of corresponding hydroxyl‐ terminated oligomers in the presence of highly reactive decafluorobiphenyl (DFB) as a chain extender, followed by postsulfonation with concentrated sulfuric acid. Their molecular weights were reasonably high as determined by viscosity measurement (η_inh = 0.72–1.58 dL/g). It was also confirmed that postsulfonation selectively took place in hydrophilic segments to yield highly sulfonated multiblock copolymers (IEC = 1.90–2.75 mequiv/g). The resulting polymers gave transparent, flexible, and tough membranes by solution casting. The 4b membrane, as a representative sample, demonstrated good mechanical strength in the dry state regardless of high IEC value (2.75 mequiv/g). The 4a–c membranes with higher IEC values (IEC = 2.75–2.79 mequiv/g) maintained high water uptake (13.7–17.7 wt %) at 50% RH and it was still high (7.4–8.5 wt %) at 30% RH. Proton conductivity of all membranes at 80 °C and 95% RH was higher than that of Nafion 117. Furthermore, the 4a membrane showed high proton conductivity, comparable with Nafion 117 in the range of 50–95% RH, and maintained high proton conductivity (2.3 × 10^?3 S/cm) even at 30% RH. Finally, the surface morphology of the membrane was investigated by tapping mode atomic force microscopy, which showed well‐connected hydrophilic domains that could work as proton transportation channel. This phase separation and the high water uptake behavior probably contributed to high and effective proton conduction in a wide range of relative humidity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2757–2764, 2010     

用于燃料电池质子交换膜材料的磺化聚芳醚酮砜的合成与性能研究

以叔丁基对苯二酚(TBHQ)为双酚单体,1,4-二(4′-氟苯甲酰基)苯,3,3′-二磺酸钠基-4,4′-二氧二苯砜(SDCDPS)为原料,采用亲核缩聚反应,通过调整磺化单体和非磺化单体的比例与叔丁基对苯二酚共聚,合成了一系列具有不同磺化度的聚芳醚酮砜.通过红外光谱(FTIR),TGA,DSC等分析方法对其结构及性能进行了表征.并用TEM对其内部形态进行了研究,建立了结构与性能之间的关系.通过对膜进行综合性能评价发现,磺化度为0.8的磺化聚芳醚酮砜膜的质子传导率在80℃时达到了0.061 S/cm接近了Nafion 117,而且其甲醇渗透系数为3.4×10-7cm2/s远低于Nafion 117,在质子交换膜燃料电池(PEMFC)和直接甲醇燃料(DMFC)电池中表现出了好的应用前景.     

Synthesis and properties of novel sulfonated polyimides containing binaphthyl groups as proton‐exchange membranes for fuel cells

A novel sulfonated diamine monomer, 2,2′‐bis(p‐aminophenoxy)‐1,1′‐binaphthyl‐6,6′‐disulfonic acid (BNDADS), was synthesized. A series of sulfonated polyimide copolymers containing 30–80 mol % BNDADS as a hydrophilic component were prepared. The copolymers showed excellent solubility and good film‐forming capability. Atomic force microscopy phase images clearly showed hydrophilic/hydrophobic microphase separation. The relationship between the proton conductivity and degree of sulfonation was examined. The sulfonated polyimide copolymer with 60 mol % BNDADS showed higher proton conductivity (0.0945–0.161 S/cm) at 20–80 °C in liquid water. The membranes exhibited methanol permeability from 9 × 10^?8 to 5 × 10^?7 cm²/s at 20 °C, which was much lower than that of Nafion (2 × 10^?6cm²/s). The copolymers were thermally stable up to 300 °C. The sulfonated polyimide copolymers with 30–60 mol % BNDADS showed reasonable mechanical strength; for example, the maximum tensile strength at break of the sulfonated polyimide copolymer with 40 mol % BNDADS was 80.6 MPa under high moisture conditions. The optimum concentration of BNDADS was found to be 60 mol % from the viewpoint of proton conductivity, methanol permeability, and membrane stability. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 222–231, 2007     

Synthesis and characterization of epoxy‐based semi‐interpenetrating polymer networks sulfonated polyimides proton‐exchange membranes for direct methanol fuel cell applications

Novel epoxy‐based semi‐interpenetrating polymer networks (semi‐IPNs) of aromatic polyimide, derived from 2,2‐benzidinedisulfonic acid (BDSA), were prepared through a thermal imidization reaction. Dynamic scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were utilized to verify the synchronization of the imidization of sulfonated poly(amic acid) (SPAA) and the crosslinking reactions of epoxy. The semi‐IPNs of epoxy/sulfonated polyimides (SPI‐EPX) exhibit excellent film‐forming characteristics and mechanical integrity at room temperature. Conductivities at 100 °C of 0.0243 S cm^?1 (SPI‐EP30) and 0.0141 S cm^?1 (SPI‐EP50) were obtained, which are similar to that of the Nafion 117 (0.0287 S cm^?1). The increase in the conductivity of SPI‐EP(30,40) with temperature is more rapid than that of Nafion 117. The SPI‐EPX exhibited lower methanol permeability than did Nafion117. The hydrolytic stability of the SPI‐EPX was followed by FTIR spectroscopy at regular intervals. SPI‐EPX prepared using epoxy‐based semi‐IPNs of sulfonated polyimide, SPI‐EP(40,50), exhibited higher hydrolytic stability than the phthalic polyimides (five‐membered ring polyimides).The microstructure was analyzed using atomic force microscopy (AFM) in the tapping mode, which demonstrated that SPI‐EP50 exhibited a nanophase that was separated into an essentially reticulated and venous hydrophobic and hydrophilic domains. Transmission electron microscopy (TEM) confirmed widespread and well‐connected hydrophilic domains, proving the higher hydrolytic stability and strong proton‐transporting properties of the SPI‐EPX membrane. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2262–2276, 2008     

Synthesis and properties of novel sulfonated (co)polyimides bearing sulfonated aromatic pendant groups for PEFC applications

Novel sulfonated diamines bearing aromatic pendant groups, namely, 3,5‐diamino‐3′‐sulfo‐4′‐(4‐sulfophenoxy) benzophenone (DASSPB) and 3,5‐diamino‐3′‐sulfo‐4′‐(2,4‐disulfophenoxy) benzophenone (DASDSPB), were successfully synthesized. Novel side‐chain‐type sulfonated (co)polyimides (SPIs) were synthesized from these two diamines, 1,4,5,8‐naphthalene tetracarboxylic dianhydride (NTDA) and nonsulfonated diamines such as 4,4′‐bis(3‐aminophenoxy) phenyl sulfone (BAPPS). Tough and transparent membranes of SPIs with ion exchange capacity of 1.5–2.9 meq g^?1 were prepared. They showed good solubility and high thermal stability up to 300 °C. They showed isotropic membrane swelling in water, which was different from the main‐chain‐type and sulfoalkoxy‐based side‐chain‐type SPIs. The relative humidity (RH) and temperature dependence of proton conductivity were examined. At low RH, the novel SPI membranes showed much higher conductivity than the sulfoalkoxy‐based SPIs. They showed comparable or even higher proton conductivity than Nafion 112 in water at 60 °C (>0.10 S cm^?1). The membrane of NTDA‐DASDSPB/BAPPS (1/1)‐s displayed reasonably high proton conductivities of 0.05 and 0.30 S cm^?1 at 50 and 100% RH, respectively, at 120 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2862–2872, 2006     

Sulfonated polyethersulfone Cardo membranes for direct methanol fuel cell

Novel proton conducting membranes, sulfonated polyethersulfone Cardo (SPES-C), were prepared with concentrated sulfonic acid at room temperature. The degree of sulfonation was controlled by reaction time. Their proton conductivity and methanol permeability as a function of temperature were investigated. The SPES-C membranes with 70% DS were still not water soluble and had low degree of swelling. With the level of 70% sulfonation, proton conductivity was 0.011 S/cm at 80 °C, 0.0338 S/cm at 110 °C, which approached that of Nafion^® 115 membrane at the same conditions. Methanol permeability of SPES-C membranes was considerably smaller than that of Nafion^® 115 membrane over the temperature 25–80 °C.     

Synthesis and characterization of proton‐conducting copolyimides bearing pendant sulfonic acid groups

A series of sulfonated copolyimides (co‐SPIs) bearing pendant sulfonic acid groups were synthesized from 1,4,5,8‐naphthalenetetracarboxylic dianhydride (NTDA), bis(3‐sulfopropoxy) benzidines (BSPBs), and common nonsulfonated diamines via statistical or sequenced polycondensation reactions. Membranes were prepared by casting their m‐cresol solutions. The co‐SPI membrane had a microphase‐separated structure composed of hydrophilic and hydrophobic domains, but the connecting behavior of hydrophilic domains was different from that of the homo‐SPIs. The co‐SPI membranes displayed clear anisotropic membrane swelling in water with negligibly small dimensional changes in the plane direction of the membrane. With water uptake values of 39–94 wt %, they showed dimensional changes in membrane thickness of about 0.11–0.58, which were much lower than those of homo‐SPIs. The proton conductivity σ values of co‐SPI membranes with ion exchange capacity values ranging from 1.95–2.32 meq/g increased sigmoidally with increasing relative humidity. They displayed σ values of 0.05–0.16 S/cm at 50 °C in liquid water. Increasing temperature up to 120 °C resulted in further increase in proton conductivity. The co‐SPI membranes showed relatively good conductivity stability during the aging treatment in water at 100 °C for 300 h. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1545–1553, 2005     

侧链磺化聚芳醚质子交换膜的研究进展

燃料电池是以氢气、甲醇等作为燃料的一种新型能量转化装置,其中质子交换膜燃料电池（Proton Exchange Membrane Fuel Cell, PEMFC）凭借其能量功率高、启动速度快和使用寿命长等优点已经在移动电源、潜艇和电动汽车等领域得到了广泛应用。质子交换膜（Proton Exchange Membrane, PEM）对PEMFC的性能影响最大,高效的PEMFC需要PEM具有高的质子电导率、良好的热稳定性和机械性能、低燃料渗透率以及优异的物理化学稳定性等。目前市面上多数使用的均是具有优异质子电导率的Nafion系列膜,但其存在制备困难、成本昂贵、质子电导率严重依赖湿度等缺点,在一定程度上限制了其发展。为了让PEM有更多的选择,科学家一直专注于使用新材料替代Nafion膜。近年来,科学家们模拟Nafion结构,通过合成各种侧链含磺酸基团的聚芳醚结构,使得亲水基团磺酸基和疏水基团之间形成微相分离结构,从而获得了一系列具有优异综合性能的PEM。本文将重点对侧链烷基磺化型、侧链磺化嵌段型、侧链局部密集磺化型、侧链磺化交联型和侧链磺化复合型这几种常见策略的合成方法及性能进行了综述,最后展望了侧链磺化聚芳醚在PEM领域的优势及发展前景。     

含甲基磺化杂萘联苯聚醚砜酮质子交换膜材料的合成与性能

以4-(3,5-二甲基-4-羟基苯基)2,3-二氮杂萘-1-酮,3,3′-二磺酸钠-4,4′-二氟苯甲酮和4,4′-二氯二苯砜为原料,利用亲核缩聚反应,通过改变磺化单体的含量,制备出一系列不同磺化度的杂萘联苯聚醚砜酮(SPPESK-DM).采用FTIR、1H-NMR表征了聚合物的结构,热失重分析仪研究了聚合物的耐热稳定性,以N-甲基-2-吡咯烷酮为溶剂采用溶液浇铸法成膜研究该系列聚合物膜的性能.结果表明,SPPESK-DM磺酸基的热分解温度在260℃以上,主链分解温度在410℃以上;膜的吸水率、溶胀率、离子交换容量和质子传导率均随着磺化度的增大而增大,磺化度为1.0的SPPESK-DM50的质子传导率达到1.08×10-2S/cm(85℃),且甲醇渗透系数为2.06×10-7cm2/s,低于Nafion117膜的甲醇渗透系数(2×10-6cm2/s).此系列膜的耐氧化性比较优异,可望用于质子交换膜燃料电池中.     

Anhydrous state proton conduction in sulfonated bisphenol a polyetherimide with 1H‐1,2,4 triazole as proton solvent

In this study, bisphenol A polyetherimide was sulfonated to various degrees (22, 48, and 62%) by trimethylsilylchlorosulfonate (TMSCS). Novel anhydrous proton conducting polyelectrolytes were prepared by the incorporation of 1H‐1,2,4‐triazole (Taz) as proton solvent in sulfonated polyetherimide (SPEI) matrix. The conductivity reached about 2 × 10^–3 S/cm at 80 °C and 10^–2 S/cm at 140 °C. The temperature dependence proton conductivity of the polyelectrolytes followed Arrhenius equation. The conductivity improved considerably at a temperature close to the triazole melting temperature in SPEI(X)H matrix. It was proposed that the high mobility of the triazolium ions (vehicle diffusion), in addition to structure diffusion, contribute to the high conductivity of these proton conducting electrolytes above the melting temperature of triazole. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2178–2187, 2009     

Sulfonated silica‐based electrolyte nanocomposite membranes

New functionalized particles were prepared by attaching sulfonated aromatic bishydroxy compounds onto fumed silica surface. First, a bromophenyl group was introduced onto the silica surface by reaction of bromophenyltrimethoxysilane with fumed silica. Then, sulfonated bishydroxy aromatic compounds were chemically attached to the silica surface by nucleophilic substitution reactions. The structure of the modified silica was characterized by elemental analysis: ¹³C‐NMR, ²⁹Si‐NMR, and FTIR. Afterward, novel inorganic–organic electrolyte composite membranes based on sulfonated poly(ether ether ketone) have been developed using the sulfonated aromatic bishydroxy compounds chemically attached onto the fumed silica surface. The composite membrane prepared using silica with sulfonated hydroxytelechelic, containing 1,3,4‐oxadiazole units, has higher proton conductivity values in all range of temperatures (40–140 °C) than the membrane containing only the plain electrolyte polymer, while the methanol permeability determined by pervaporation experiment was unchanged. A proton conductivity up to 59 mS cm^?1 at 140 °C was obtained. The combination of these effects may lead to significant improvement in fuel cells (fed with hydrogen or methanol) at temperatures above 100 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2278–2298, 2006