Crosslinked poly(vinyl alcohol) membranes containing sulfonic acid group: proton and methanol transport through membranes

Increases in the proton conductivity and selectivity of proton exchange membranes for direct methanol fuel cells by formation of nanocomposites having proton conducting channels

“…The presence of additional water enhances proton conductivity via enhancement of proton mobility, as opposed to additional water which lowers conductivity through the dilution effect. In the reported literature [48][49][50][51], the water absorbed in the membrane can be divided broadly into two groups of bound water and free water. The bound water is the state of water associated with the membrane matrix whereas the free water is not.…”

“…The addition of SA-SNP to SPAEEKK could possibly further enhance proton conductivity through restructuring hydrophilic channels in the membrane [50]. The sulfonic acid groups attached to the silica surfaces have restricted motion in the polymer matrix due to the interactions between the sulfonic particle and matrix.…”

“…Hacker et al also pointed out that the Fantod's test is not a sufficient gauge for hydrocarbon membranes for DMFCs [51]. On the other hand, the hydrolytic stability of the membranes was examined by immersing the membranes in boiling water for 8 days [50]. Fig.…”

Synthesis and characterization of poly(vinyl alcohol) proton exchange membranes modified with 4,4-diaminodiphenylether-2,2-disulfonic acid

“…Nafion developed by DuPont evoked the greatest interest because of its combined chemical, electrochemical, and mechanical stabilities with high proton conductivity (~0.1 S·cm -1 ) at ambient temperature [2]. However, this still limits the wide applications due to its high cost, high methanol permeability (~10 -6 cm 2 /s) and difficulty in synthesis and processing [3,4]. The high methanol permeability allows the undesired transport of methanol from the anode side of the fuel cell, through the membrane, to the cathode side, a phenomenon known as methanol crossover.…”

“…The high methanol permeability allows the undesired transport of methanol from the anode side of the fuel cell, through the membrane, to the cathode side, a phenomenon known as methanol crossover. As a consequence, excessive methanol permeability of any polymer electrolyte membrane (PEM) leads to an unacceptable decrease in cell performance [4,5]. To address the problem of methanol crossover, numerous membranes as alternatives to Nafion have been developed and studied.…”