Enhancement of Proton Transport by Nanochannels in Comb‐Shaped Copoly(arylene ether sulfone)s

Abstract

Combed to perfection: Fully aromatic comb‐shaped copolymers based on a poly(arylene ether sulfone) (PAES) backbone with highly sulfonated (SA) poly(phenylene oxide) (PPO) graft chains have a nanochannel morphology (see picture) for efficient proton transport. These molecular structures show a dramatic enhancement in proton conductivity under partially hydrated conditions compared with typical hydrocarbon polymer electrolytes.

Ion Transport by Nanochannels in Ion-Containing Aromatic Copolymers

“…A comparison of the morphology of two of the copolymers having similar IEC values, one with more periodic but shorter grafts (X5-Y9, IEC 1.28 mequiv/g) and one with less periodic but longer grafts (X3-Y14, IEC 1.26 mequiv/g), suggests that the latter copolymer has the highest interconnectivity in the ionic domains. 24 Paradoxically, the former copolymer has significantly higher proton conductivity, which could possibly be explained by the more periodic shorter graft chains being distributed more homogeneously than the less periodic longer graft counterparts. The interconnectivity of ionic clusters was very pronounced for the copolymer with the highest IEC (X5-Y14, IEC 1.72 mequiv/g), with nanochannel sizes in the range of 15−20 nm.…”

Fluorinated Poly(Arylene Ether)s

“…Guiver's group prepared comb-shaped densely sulfonated fluorinated PAEs [165] in which the grafted side chain contained two sulfonic acid groups per unit. The IEC value of the comb-shaped copolymers ranged from 0.92 to 1.72 mEq./g.…”

Proton Mobility in Sulfonated PolyEtherEtherKetone (SPEEK): Influence of Thermal Crosslinking and Annealing

“…These nanodomains percolate above a critical concentration of water (or below a certain proton concentration in the acidic solutions present in the hydrophilic domains) [7][8][9]. The resulting nanocomposite combines very attractive properties for use in demanding environments, such as on the one hand high chemical and thermal stability and good mechanical properties, due to relatively strong and rigid bonds in and between the aromatic rings, and on the other hand high proton conductivity, due to the dissociated and hydrated protons migrating in the acidic solution [10][11][12][13][14]. This microstructure allows responding to a general dilemma found in all solid electrolytes, i.e., that a high ionic conductivity is related to a low thermodynamic and mechanical stability.…”