Molecular branching as a simple approach to improving polymer electrolyte membranes

Does power ultrasound affect hydrocarbon Ionomers?

“…Fabrication of the catalyst inks for PEMFCs typically involves addition of appreciable amounts of Pt catalyst on carbon support, relative to the ionomer, followed by dispersion, or homogenization, via power ultrasound (e.g., in an ultrasonication bath). For instance, catalyst inks containing Nafion® D520 ionomer are typically prepared with 0.30 wt% ionomer and 0.70 wt% Pt/C [10] , [13] , whereas hydrocarbon-based catalyst inks range from 0.15 to 0.30 wt% ionomer, and 0.85 – 0.70 wt% Pt/C [11] , [13] , [47] . In both cases, 99.0 wt% of the ink is solvent/dispersant.…”

Effect of steric constraints on the physico‐electrochemical properties of sulfonated polyaromatic copolymers

“…[23][24][25] Within this subset of aromatic-hydrocarbon-based PEMs exists a multitude of synthetic strategies to obtain various chemical architectures from comparatively lowcost starting materials. Common examples include sulfonated derivatives of poly(arylene ether sulfone)s, [26][27][28][29] poly(ether ether ketone)s, 13,30 poly(phenylene oxide)s, 31 poly(benzimidazole) s, [32][33][34][35] poly(imide)s 36 and poly(phenylene)s. [37][38][39][40][41][42] Of the numerous hydrocarbon-based structures examined in the literature to date, recent developments on sulfonated poly(phenylene)s have been particularly promising. These polymers, which are composed wholly of aryl-aryl linkages devoid of labile heteroatomic linkages, are potentially more resilient to oxidative degradation than other hydrocarbon PEMs, both ex situ 25,37,38,40,41 and in situ.…”

“…38,40 Within this class of hydrocarbonbased PEMs, proton conductivity values of up to 338 mS cm −1 41 and Young's moduli and tensile strength of up to 1616 and 62 Mpa, respectively, with respectable elongations at break have been reported. 42 Historically, work in this area had been limited by poor solubility in polar solvents and the challenge of synthesizing well-defined and precisely functionalized polymer structures. 43,44 Many of the traditional disadvantages associated with poly(phenylene)s such as poor solubility and poor membrane flexibility, however, have been overcome in recent years.…”

“…Within this subset of aromatic‐hydrocarbon‐based PEMs exists a multitude of synthetic strategies to obtain various chemical architectures from comparatively low‐cost starting materials. Common examples include sulfonated derivatives of poly(arylene ether sulfone)s, 26–29 poly(ether ether ketone)s, 13,30 poly(phenylene oxide)s, 31 poly(benzimidazole)s, 32–35 poly(imide)s 36 and poly(phenylene)s 37–42 …”

“…These polymers, which are composed wholly of aryl–aryl linkages devoid of labile heteroatomic linkages, are potentially more resilient to oxidative degradation than other hydrocarbon PEMs, both ex situ 25,37,38,40,41 and in situ 38,40 . Within this class of hydrocarbon‐based PEMs, proton conductivity values of up to 338 mS cm −1 41 and Young's moduli and tensile strength of up to 1616 and 62 Mpa, respectively, with respectable elongations at break have been reported 42 . Historically, work in this area had been limited by poor solubility in polar solvents and the challenge of synthesizing well‐defined and precisely functionalized polymer structures 43,44 .…”