Proton‐conductive membranes based on blends of polyimides

Abstract

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 8C, 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.

Tuning transport properties by manipulating the phase segregation of tetramethyldisiloxane segments in modified polyimide electrolytes

“…Various sulfonated aromatic polymers, such as: poly(aryl ether sulfone) [3][4][5][6], poly(ether ketone) [7,8], polyimide (PI) [9][10][11][12][13][14][15][16][17][18], Polybenzimidazole (PBI) [19][20][21][22][23], etc. have been proposed as alternative membrane materials.…”

Proton conductive membranes based on poly(styrene-co-allyl alcohol) Semi-IPN

“…Due to the continuous structure observed in SEM images and the good homogeneity detected, there is no evidence of phase separation in the system, as pointed by other authors for the characterization of IPN and blend membranes [13] . The surface continuity and compactness observed for the DGEBA/PSAA Semi-IPN membranes is key for its application in FC devices, since fuel crossover must be avoided and membrane porosity is one of the main factors influencing this characteristic.…”

Electrospun nanofibrous blend membranes for fuel cell electrolytes

“…The proton conductivity of the blend membranes containing nanofibers was measured by electrochemical impedance spec- troscopy over the frequency range from 50 Hz to 50 kHz (Hioki 3532-50, Tokyo, Japan) as reported in previous papers [9,10]. The blend membranes (1.0 cm × 3.0 cm) and two blackened platinum plate electrodes were placed in a Teflon cell.…”

“…The water uptake of the blend membrane containing nanofibers was gravimetrically measured from the dried and humidified membranes [9,10]. The membranes were dried in a vacuum oven at 80 • C for 10 h and then immersed in liquid water at room temperature.…”

“…However, there are several drawbacks of Nafion, such as high cost, low thermal stability, and high gas permeability. Recently, numerous research efforts are focusing on the development of novel polymer electrolyte membranes based on the sulfonated aromatic hydrocarbon polymers, which have been widely synthesized as alternate candidates due to their excellent chemical and thermal stabilities, and good mechanical strength [5][6][7][8][9][10]. However, most of them contain a large number of sulfonic acid groups to enhance the proton conductivity, resulting in an unfavorable swelling of the membranes and a dramatic loss in their mechanical properties.…”