Difluorodiphenyl Sulfone Research Articles

Design and synthesis of low‐dieclectric polyaryl ethers containing bulky tetraphenyl vinyl pendant group

AbstractA tetraphenylethylene‐containing bisphenol monomer 5‐[4‐(triphenylvinyl)phenyl]benzene‐1,3‐diol (TPE‐OH) was designed and synthesized by Suzuki coupling and nucleophilic substitution reaction. By adjusting the proportion of TPE‐OH, a series of rigid polyaryl ether, namely PPTES, were facilely synthesized by homopolymerization or copolymerization with 4‐(4‐hydroxyphenyl)‐2,3‐diazepine‐1‐one (DHPZ) and 4,4′‐difluorodiphenyl sulfone (DFS). The following characterization of their structures with nuclear magnetic resonance and infrared spectroscopy confirmed successful synthesis of both monomers and polymers. Large, volume‐twisted and non‐coplanar rigid tetraphenylethylene could effectively increase the molecular chain spacing and reduce the regularity of the molecular chain, as evidenced by molecular dynamics simulation with Materials Studio, in turn to form an amorphous nature of PPTES phase state. In addition, such PPTESs have excellent solubility, heat resistance, and other comprehensive properties. Their glass transition temperature (Tg) is between 219 and 300°C, and the 5% thermogravimetric temperature of PPTESs locates at 490–539°C under N2 atmosphere. At 1 GHz, the intrinsic dielectric permittivity of polymer films is between 2.32 and 2.61, gradually decreases with TPE‐OH content. This work would provide new idea and choice for the selection of polyaryl ether resin bisphenol monomer, and promote the development and application of low‐dielectric polyarylether materials.

Fluorination as a powerful tool for improving water/salt selectivity of hydrophilic polyethersulfone

Fluorination is an important tool for tuning polymer free volume properties, but the effect of fluorination on the water/salt transport properties of desalting polymers remains uncertain. In this work, a series of novel cysteine-based polyethersulfones (PES-Cys and PES-Cys-2F, PES-Cys-6H and PES-Cys-6F, PES-Cys-8H, and PES-Cys-8F) were designed in pair (4,4'-difluorodiphenyl sulfone versus 3,3',4,4'-tetrafluorodiphenyl sulfone, bisphenol A versus hexafluorobisphenol A, and 4,4'-dihydroxybiphenyl versus decafluorobiphenyl). Upon casting into membranes via the solvent evaporation method, the membranes/polymers were characterized by 1H NMR, FTIR, XRD, DSC, Zeta potential, and the water/salt transport properties of the membranes was investigated systematically. It has been demonstrated that fluorination brings out greater spatial site resistance, stronger hydrophobicity, and higher electronegativity to polyethersulfone chains, leading to decreased water sorption but increased salt sorption. Fluorinated polyethersulfone displayed higher water diffusion coefficient because the C–F group can shatter water clusters into water molecules, which can diffuse more rapidly. Fluorinated polyethersulfone exhibit superior water/salt selectivity, with the most rigid PES-Cys-8F of the highest fluorine content showing water/salt selectivity over the empirical upper bound line. The enhanced water/salt selectivity is mostly because that fluorination improves water permeability by significantly increasing the water diffusion coefficient, while the electrostatic barrier provided by the electronegative fluorine atoms inhibits salt diffusion. This study provides valuable theoretical guidance for future molecular design of antioxidant desalting polymers.

Enhanced performance of proton-conducting poly(arylene ether sulfone)s via multiple alkylsulfonated side-chains and block copolymer structures

A novel difluoro aromatic monomer DFTMTE is prepared, which contains five pendant ionizable methoxy and crosslinkable ethanedione groups. Block copolymers are developed via block copolycondensation of the monomers DFTMTE, 4,4′-difluorodiphenyl sulfone and 4,4′-diphenol. Sulfonated block ionomers are obtained via the following demethylation and nucleophilic substitution of the copolymers. The ionomer membranes with ion exchange capacity (IEC) of 1.80–2.16 mequiv. g−1 display high conductivity of 234–319 mS cm−1 at 80 °C and large maximum power density of 1730–2140 mW cm−2, which is obviously larger than Nafion 212 (117 mS cm−1 and 1350 mW cm−2) in the same condition. Their enhanced performances are attributed to excellent microphase separations caused by block copolymer structures and multiple sulfonated side-chains integrating both rigid aromatic and flexible aliphatic units. Meanwhile, crosslinking further improves the balance among the properties of the membranes. For example, CB1SP having IEC of 1.80 mequiv. g−1 displays high comprehensive performance because of DFTMTE units and crosslinking structures, wherein low membrane swelling below 15% at 80 °C, large conductivity of 234 mS cm−1, high maximum power density of 1730 mW cm−2 and good stability of the membrane electrolyte assembly indicate a high potential in the application of fuel cell.

Robust three‐dimensionally printed polypropylene/highly sulfonated polysulfone composites for potential applications in fuel cells

Advanced ion-conducting composites were prepared by ionomer synthesis, fused deposition modeling (FDM) 3D-printing, surface modification, and pore-filling. The cost-effective, mechanically robust, and inert microporous substrates of polypropylene were made by FDM printing. Three infill contents of 30, 50, and 70 vol% of polypropylene were designed. A synthesized highly sulfonated hydroquinone-based polysulfone, with 80% degree of sulfonation (DS), was used as the pore material. Nucleophilic aromatic substitution on difluorodiphenyl sulfone was used to synthesize the highly sulfonated ionomer. Pore-filling of the designed printed substrate was done via 10 w/v% of the ionomer solution. Oxygen plasma treatment was applied to enhance the compatibility of the substrate and the pore material's interfaces. Modification of porous substrate was confirmed by alteration of surface polar characteristics and roughness from contact angle measurements and atomic force microscopy, respectively. Confinement of highly sulfonated ionomer by the robust structure resulted in the preparation of electrolyte with controlled water uptake, no in-plane swelling, high conductivity (up to 0.417 S/cm at 60°C under 100% relative humidity), and current density of about 836 mA.cm−2 at 60°C under 100% relative humidity. Regarding the presence of commodity polypropylene in the structure, the performance was good, compared to commercial Nafion membrane, with a cell current density of about 1120 mA.cm−2.

Poly(arylene ether sulfone)s with different positions of pyridyl groups: Synthesis of the basic diphenyl sulfone dihalide monomers in lithiation and the optimal polymerization in condensation

The present study consists of three parts: 1) synthesis of diphenyl sulfone dihalide monomers with different positions of pyridyl groups; 2) fundamental understanding of polymer chain growth (i.e., condensation) and scission (i.e., trans-etherification) involving use of the novel dihalides; and 3) general properties of the basic polymers prepared. The dihalides are 4,4′-difluorodiphenyl sulfone contained with pyridyl groups where the nitrogen atom is in either ortho- or para-position to the ketone bridges, synthesized via lithiation using n-butyl lithium and the corresponding electrophiles. Both dihalides were found to be thermally stable up to 250 °C and their melting points were 222 and 206 °C, respectively. Their versatilities for K2CO3-mediated poly-condensation were confirmed with a careful control of reaction time, temperatures and solvents to depress trans-etherification and cross-linking reactions with an activation energy sufficiently for polymer chain growth. Consequently, the optimal conditions were 130 °C for 24 h in dimethylacetamide that resulted in polymer products with high molecular weights (Mw) ranging from 40 to 200 kDa. The glass transition points of poly(arylene ether sufone)s (PAESs) with pyridyl groups in the para-positions were higher than those of PAESs with pyridyl groups in the ortho-positions under a given Mw, and the thermal decomposition points were higher for PAESs in the ortho-positions than in the para-positions under a given degree of pyridyl substitution. These findings would consequently open up many synthetic routes towards various kinds of monomers and polymers via metalation and condensation reaction schemes.

Synthesis and properties of poly(arylene ether sulfone) anion exchange membranes with pendant benzyl-quaternary ammonium groups

A series of side-chain type poly(arylene ether sulfone)s (sPAE) bearing pendant 3,5-dimethylphenyl groups are prepared via high temperature polycondensation reaction of 4,4’-biphenol, 4,4'-difluorodiphenyl sulfone, and new difluoro aromatic ketone monomer, (2,6-difluorophenyl) [3-[(3,5-dimethylphenyl)methyl]-5-methylphenyl] methanone. The sPAE-based anion exchange membranes (sQPAE(x/y)) containing pendant benzyl-quaternary ammonium groups are obtained by the corresponding bromomethylation of sPAE and subsequent quaternization. The obtained side-chain type membranes sQPAE(x/y) display anisotropic membrane swelling, high alkaline stability and good hydroxide conductivity in the range of 42.7–61.5 mS cm−1 at 80 °C, taking their low IECs of 0.97–1.29 mequiv g−1 into consideration. Their high hydroxide conductivity is attributed to the greater length and dense distribution of the pendant benzyl-quaternary ammonium groups. Besides, the crosslinked membrane sCQPAE(1/4) is prepared via quaternization reaction between brominated sPAE and crosslinker. Compared to the uncrosslinked membrane, sCQPAE(1/4) with same IEC shows lower membrane swelling, better oxidative stability, higher conductivity and chemical stability at 80 °C.

Synthesis and properties of hydroxide conductive polymers carrying dense aromatic side-chain quaternary ammonium groups

A series of hydroxide conductive polymers QTBMs carrying dense aromatic side-chain quaternary ammonium groups has been synthesized by using a new monomer of 3,3′-di(3″,5″-dimethylphenyl)-4,4′-difluorodiphenyl sulfone and other commercial monomers via polycondensation reaction, and subsequent bromination, quaternization and alkalization. The chemical structures of the ionomers were confirmed by 1H- and 13C-NMR spectroscopy. Water uptake, swelling ratio, hydroxide conductivity, the number of bonded water per ammonium group (λ), volumetric ion exchange capacity (IECVwet), mechanical and thermal properties, and chemical stability were systematically evaluated for the series of QTBMs membranes. QTBMs showed IECs ranging from 1.02 meq·g−1 to 2.11 meq·g−1; in particular, QTBM-60 membrane with the highest IEC (2.11 meq·g−1) had very high hydroxide ion conductivity of 131.9 mS·cm−1 at 80 °C, which was attributed to the well assembled nano-channels with distinct phase separation evidenced by small-angle X-ray scattering (SAXS). It was found that the hydrated QTBMs membranes were mechanically stable with moderate water uptakes and swelling ratios, high chemical stability under the harsh alkaline conditions. This work provides a facile way to prepare anion exchange membranes (AEMs) with high performances for the application in alkaline fuel cells.

Effects of sulfonated side chains used in polysulfone based PEMs for VRFB separator

Polysulfone (PSU) –based Proton Exchange Membranes (PEMs) were synthesized from different pre-sulfonated monomers and evaluated for use in a vanadium redox flow battery (VRFB). Two types of sulfonated monomers, containing either an allyl sulfonate or styrene sulfonate group, were synthesized by a Mizoroki-Heck reaction from a 4,4′-difluorodiphenyl sulfone derivative. These monomers were polymerized with 4,4′-(hexafluoroisopropylidene)diphenol to give partially fluorinated PSUs with controlled placement and content of sulfuric acid moieties. PEMs were then fabricated by solution casting and characterized against the membranes made from traditional backbone sulfonated PSU. The new PEMs revealed desirable physical properties and performance in a VRFB cell competitive with the Nafion membrane. Furthermore, each PEM with a different acid side-chain structure exhibited varying properties and performance depending on its acid content, providing a path to optimization.

Synthesis of organosoluble and transparent phenolphthalein-based cardo poly(ether sulfone imide)s via aromatic nucleophilic substitution polymerization

A series of cardo poly(ether sulfone imide)s (PESI-C) containing bulky phthalide groups were prepared via aromatic nucleophilic substitution reaction of phenolphthalein with 4,4′-difluorodiphenyl sulfone and 4,4′-bis(4-fluorophthalimido)diphenyl ether (BFPI). The glass transition temperatures and 5% weight loss temperatures in nitrogen of the resulting PESI-C increased from 258°C to 278°C and from 468°C to 495°C with increasing the content of imide moiety in the polymer chain, respectively. These PESI-C films were transparent and essentially colorless and exhibited good mechanical properties with tensile strengths of 91–124 MPa, elongations at break of 6.9–12.8%, and tensile moduli of 2.2–2.8 GPa, respectively. It is noted that the tensile strengths, elongations at break, and tensile moduli of PESI-C also increased with increasing the content of BFPI in the copolymerization, indicating that the properties could be adjusted by controlling the ratio of BFPI and 4,4′-difluorodiphenyl sulfone.

Fluorenyl‐containing Quaternary Ammonium Poly(arylene ether sulfone)s for Anion Exchange Membrane Applications

AbstractA series of anion exchange membranes (AEM) based on block quaternary ammonium poly(arylene ether sulfone) (QA‐bPAES) were successfully synthesized from 9,9′‐bis(4‐hydroxyphenyl) fluorene, 4,4′‐(hexafluoroisopropylidene) diphenol and 4,4′‐difluorodiphenyl sulfone via block polymerization, chloromethylation, quaternization, alkalization and solution casting. Properties of the obtained QA‐bPAES membranes, including ion exchange capacity (IEC), water uptake, swelling ratios, methanol permeability and ion conductivity were investigated. The obtained QA‐bPAES membranes showed low water uptakes, high ion conductivities and good physical and chemical stability. For example, the membrane of QA‐bPAES(20/10)‐1.34 with IEC of 1.34 mmol g−1 exhibited swelling ratios of 5.0% and 5.1% in in‐plane and through‐plane direction, respectively, and ion conductivity of 15.6 mS cm−1 in water at 60 °C with low methanol permeability of 1.06 × 10−7 cm2 s−1 (25 °C). All the results indicated that this type of block membranes had good potentials for alkaline anion exchange membrane fuel cell applications.

High temperature, flame-retardant, and transparent epoxy thermosets prepared from an acetovanillone-based hydroxyl poly(ether sulfone) and commercial epoxy resins

A phosphinated biphenol, 6-(1-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)ethyl)-6H-dibenzo[c,e] [1,2]oxaphosphinine 6-oxide (1), was synthesized from a sustainable phenol, acetovanillone. A methoxy-substituted poly(ether sulfone), methoxy-PES-1, was successfully prepared by the nucleophilic substitution of (1) and difluorodiphenyl sulfone in the presence of potassium carbonate. Another phosphinated biphenol, 6-((4-hydroxy-3-methoxyphenyl)(4-hydroxyphenyl)methyl)-6H-dibenzo[c,e] [1,2]oxaphosphinine 6-oxide (2), was prepared from another sustainable phenol, vanillin. However, the preparation of the methoxy-substituted poly(ether sulfone) based on biphenol (2) is not successful due to the biphenol (2) being unstable in an alkaline condition. After demethylation of the methoxy-PES-1, a phenolic hydroxyl poly(ether sulfone), hydroxyl-PES-1, was obtained. The phenolic hydroxyl linkages of the hydroxyl-PES-1 act as reacting sites for the epoxy resins. High-performance, bendable, flame retardant, and unexpectedly transparent cured epoxy film can be achieved through the curing of hydroxyl-PES-1 with commercially-available epoxy resins.

Side-chain-type poly(arylene ether sulfone)s containing multiple quaternary ammonium groups as anion exchange membranes

A new difluorodiphenyl sulfone monomer, 3,3′,5,5′-tetra(3′′,5′′- dimethylphenyl)-4,4′-difluorodiphenyl sulfone (M-DFDPS), was synthesized and further polymerized to form a series of poly(arylene ether sulfone)s containing four pendent 3,5-dimethylphenyl groups. After bromination of benzylmethyl groups, side-chain-type poly(arylene ether sulfone)s containing multiple quaternary ammonium groups in pendant phenyl rings (PAES-Q-xx) were prepared by quaternization. Their chemical structures and some properties, including water uptake, swelling ratio, hydroxide conductivities, and thermal and alkaline stabilities, were investigated. These PAES-Q-xx membranes with IEC values of 1.65–2.36 mequiv/g had low water uptake and swelling ratio. Their conductivities were all above 10mS/cm and the values were in the range of 23–37 and 54–82mS/cm at 20 and 80°C, respectively. The good conductivity is probably due to the high IEC and the dense distribution of the pendant quaternary ammonium groups. In addition, PAES-Q-xx membranes also displayed good thermal and alkaline stabilities.

Sulfonated poly (arylene ether sulfone) proton exchange membranes for fuel cell applications

AbstractSulfonated poly (arylene ether sulfone) membranes were synthesized by direct copolymerization of 4,4-bis (4-hydroxyphenyl) valeric acid, 4,4′-difluorodiphenyl sulfone and synthesized sulfonated 6F-bisphenol-A/bisphenol-A as novel proton exchange membranes for fuel cell applications. Prepared membranes were subsequently crosslinked with synthesized 6F-bisphenol-A based epoxy resin (EFN) by thermal curing reaction keeping in view the resilience and toughness of the membranes. The structural characterization was done by using Fourier transform infrared (FTIR),

Synthesis and properties of highly branched star-shaped sulfonated block poly(arylene ether)s as proton exchange membranes

Star-shaped sulfonated block copoly(ether ketone)s exhibit excellent properties for use as proton exchange membranes (PEMs). However, very few investigations of the use of highly branched star-shaped sulfonated block polymers as PEMs have been reported. In this work, two types of highly branched star-shaped sulfonated block poly(arylene ether)s with 6% branching agent were synthesized via direct polycondensation reactions of a trifunctional core (branching agent) with sulfonated 4,4′-difluorobenzophenone, bisphenol fluorene, and 4,4′-difluorodiphenyl sulfone. The properties of a polymer with hydrophilic segments surrounded by hydrophobic segments (P1) and a polymer with hydrophobic segments surrounded by hydrophilic segments (P2) were investigated. The block polymer P1 exhibited better oxidative stability (332min) and dimensional stability (<12%) than the highly branched sulfonated random polymer (P3), whereas P2 exhibited higher proton conductivity (0.40Scm−1 at 80°C) and water uptake (59.1% at 80°C) than P3. The highly branched star-shaped sulfonated block poly(arylene ether)s exhibit greater potential than P3 for use as PEMs.

Assessing the influence of side-chain and main-chain aromatic benzyltrimethyl ammonium on anion exchange membranes.

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.

Synthesis of highly branched sulfonated polymers and the effects of degree of branching on properties of branched sulfonated polymers as proton exchange membranes

Branched sulfonated polymers exhibit excellent properties as proton exchange membranes (PEMs). However, very few highly branched sulfonated polymers are reported as PEMs. The highly branched polymer, including the method to increase degree of branching (DB) and the effects of DB on the properties of PEMs, should be further studied. In this work, novel branched sulfonated poly(fluorenyl ether ketone sulfone)s with different DB value are synthesized by direct polycondensation reactions from bisphenol fluorene (A2), sulfonated 4,4′-difluorobenzphenone, 1,3,5-tris(4-(4-fluorophenylsulfonyl)phenyl)benzene (B3-3) and 4,4′-difluorodiphenyl sulfone. The highest DB with 10% branching agent is obtained using the B3-3 monomer. The method to increase the DB is discussed. It is found that B3 scaffold with long and hard arms can effectively increase the DB value. The effects of DB on the properties, including oxidative stability, proton conductivity, water uptake, swelling ratio, thermal stability, mechanical property and microstructure, are investigated. With increasing DB value, oxidative stability and proton conductivity of the membranes increase remarkably, but swelling ratio and tensile strength decrease slowly. The membrane with the highest DB value (10%) exhibits high proton conductivity (0.42 S cm−1) and oxidative stability (327 min), as well as relatively low swelling ratio (16.2%) at 80 °C.

Covalent‐ionically crosslinked sulfonated poly(arylene ether sulfone)s bearing quinoxaline crosslinkages as proton exchange membranes

AbstractCrosslinkable sulfonated poly(arylene ether sulfone)s (SPAESs) were synthesized by copolymerization of 4,4′‐biphenol with 2,6‐difluorobenzil, 4,4′‐difluorodiphenyl sulfone, and 3,3′‐disulfonated‐4,4′‐difluorodiphenyl sulfone disodium salt. The corresponding covalent‐ionically crosslinked SPAESs were prepared via the cyclocondensation reaction of benzil moieties in polymer chain with 3,3′‐diaminobenzidine. The crosslinking significantly improved the membrane performance, that is, the crosslinked membranes had the lower membrane dimensional swelling, lower methanol permeability, and higher oxidative stability than the corresponding precursor membranes, with keeping the reasonably high proton conductivity. The crosslinked membrane (CS5) with measured ion exchange capacity of 1.47 meq g−1 showed a reasonably high proton conductivity of 112 mS cm−1 with water uptake of 42 wt % at 80°C, and exhibited a low methanol permeability of 2.1 × 10−7 cm2 s−1 for 32 wt % methanol solution at 25°C. The crosslinked SPAES membranes have potential for PEFC and DMFCs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Studies on the Relationship of Polymer Backbone Rigidity and Properties for Proton Exchange Membranes Derived from Sulfonated Polys(Arylene Ether Sulfone)

A series of novel sulfonated poly(arylene ether sulfone) (SPAES) copolymers were successfully synthesized from hexafluoro bisphenol A (6F-BPA), 9,9’-bis(4-hydroxyphenyl) fluorene (BHPF), 4,4’-difluorodiphenyl sulfone (DFDPS) and 3,3’-disulfonate-4,4’-difluorodiphenyl sulfone (SDFDPS) via aromatic nucleophilic substitution polymerization, and subsequently used to prepare proton exchange membranes. By adjusting the ratio of 6F-BPA to BHPF, the influence of the rigidity of polymer backbone on the properties of the prepared membranes was investigated in detail. The results indicated that the SPAES membranes had better stability towards water but lowered water uptake and proton conductivity with the increase in the polymer backbone rigidity.

Crosslinked sulfonated poly(arylene ether sulfone) membranes for fuel cell application

A series of sulfonated poly(arylene ether sulfone) with photocrosslinkable moieties is successfully synthesized by direct copolymerization of 3,3′-disulfonated 4,4′-difluorodiphenyl sulfone (SDFDPS) and 4,4′-difluorodiphenyl sulfone (DFDPS) with 4,4′-biphenol (BP) and 1,3-bis-(4-hydroxyphenyl) propenone (BHPP). The content of crosslinkable moieties in the polymer repeat unit is controlled from 0 to 10 mol% by changing the monomer feed ratio of BHPP to BP. The polymer membranes can be crosslinked by irradiating UV with a wavelength of 365 nm. From FT-IR analysis, it can be identified that UV crosslinking mainly occurs due to the combination reaction of radicals that occurs in conjunction with the breaking of the carbon–carbon double bonds (–CH = CH-) of the chalcone moieties in the backbone. Consequently, a new bond is created to form cyclobutane. The crosslinked membranes show less water uptake, a lower level of methanol permeability, and good thermal and mechanical properties compared to pristine (non-crosslinked) membranes while maintaining a reasonable level of proton conductivity. Finally, the fuel cell performance of the crosslinked membranes is comparable to that of the Nafion 115 membrane, demonstrating that these membranes are promising candidates for use as polymer electrolyte membranes in DMFCs.

Synthesis of poly(arylene ether sulfone)s with locally and densely sulfonated pentiptycene pendants as highly conductive polymer electrolyte membranes

Poly(aryl ether sulfone)s containing sulfonated pentiptycene groups SPES- x-PPD are firstly synthesized through nucleophilic aromatic substitution polycondensation by using pentiptycene-6,13-diol, bis(4-hydroxyphenyl) sulfone and 4,4′-difluorodiphenyl sulfone, followed by postsulfonation with concentrated sulfuric acid at room temperature. The structures of SPES- x-PPD are characterized by IR, 1H NMR and 13C NMR spectra. These ionomers generally show high thermal stability. Transmission electron microscopic observations reveal that SPES- x-PPD membranes form well-defined microphase separated structures. SPES-40-PPD with the IEC value 2.36 mmol g −1 shows conductivity of 2.6 × 10 −1 S cm −1 which is much higher than that of perfluorinated Nafion 117 membrane (1.1 × 10 −1 S cm −1) at 80 °C and 94% RH. At 80 °C and 34% RH, SPES-40-PPD membrane displays the conductivity of 2.7 × 10 −3 S cm −1 which is comparable with that of Nafion 117 membrane (3.0 × 10 −3 S cm −1).