Title of article :
Synthesis and characterization of sulfonated poly(arylene ether sulfone) copolymers containing carboxyl groups for direct methanol fuel cells
Author/Authors :
Dae-Sik Kim، نويسنده , , Kwang-Ho Shin، نويسنده , , Ho Bum Park، نويسنده , , Youn Suk Chung، نويسنده , , Sang Yong Nam، نويسنده , , Young Moo Lee، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2006
Pages :
9
From page :
428
To page :
436
Abstract :
Sulfonated poly(arylene ether sulfone) copolymers derived from sulfonated 4,4′-dichlorodiphenyl sulfone (S-DCDPS), 4,4′-dichlorodiphenyl sulfone (DCDPS) and phenolphthalin (PP) were evaluated as polymer electrolyte membranes for direct methanol fuel cells. The change in ion exchange capacity, state of water content, proton conductivity, and methanol permeability with S-DCDPS content are discussed. The proton conductivity increased linearly from 5.1 × 10–3 to 4.7 × 10–2 S cm−1 at 30 °C and 95% RH with increasing sulfonation level. However, the methanol permeability increased linearly up to 20 mol% sulfonated monomer content, but then a sudden increase was observed, referred to as the “percolation threshold”, at sulfonated monomer content >20 mol%. The proton conductivity of the polymer membranes depended on the bound water and free water in the membrane, but their methanol permeability depended on the free water content. The maximum selectivity (i.e. proton conductivity/methanol permeability) of the membranes was obtained near the percolation concentration. The behavior of the proton and methanol transport mechanism is discussed in relation to the state of water in the membranes.
Keywords :
Fuel cell , Free water , Proton conductivity , Methanol permeability , Percolation threshold
Journal title :
Journal of Membrane Science
Serial Year :
2006
Journal title :
Journal of Membrane Science
Record number :
1352390
Link To Document :
بازگشت