Woo, Y Oh, SY Kang, YS Jung, B 2024-01-21T08:30:50Z 2024-01-21T08:30:50Z 2021-09-03 2003-08-01 0376-7388 https://pubs.kist.re.kr/handle/201004/138318 The sulfonated polyimide (SPI) membranes for direct methanol fuel cell (DMFC) were synthesized with 3,3,4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 2,2'-benzidinedisulfonic acid (BDSA), 4,4'-oxydianiline (ODA) through classical two-step methods: (1) preparation of sulfonated poly(amic acid) (SPAA) precursors with different sulfonation levels by controlling the molar ratio of BDSA to ODA, and (2) thermal imidization of the SPAA films. The chemical structure and the imidization from SPAA membranes were characterized by FT-IR with temperature, and the sulfonation levels were determined by elemental analysis. The thermal stability of the membranes was also characterized by TGA. From water uptake and small angle X-ray scattering (SAXS) experiments for different sulfonation levels, it was found that the number of water clusters in SPI membranes increased as the water uptake of membranes increased, but the size of water cluster was not changed with the sulfonation levels. The proton conductivity and the methanol permeability of SPI membrane showed a sudden leap like a percolation phenomenon around 35 mol% of sulfonation level. The SPI membranes exhibited relatively high proton conductivity and extremely low methanol permeability, and showed the feasibility of suitable polymer electrolyte membranes (PEM) for DMFC. (C) 2003 Elsevier B.V. All rights reserved. English ELSEVIER POLYMER ELECTROLYTE MEMBRANE PROTON CONDUCTIVITY NAFION(R) 117 CROSSOVER POLYELECTROLYTES PERFORMANCE TRANSPORT Synthesis and characterization of sulfonated polyimide membranes for direct methanol fuel cell Article 10.1016/S0376-7388(03)00185-6 1 JOURNAL OF MEMBRANE SCIENCE, v.220, no.1-2, pp.31 - 45 JOURNAL OF MEMBRANE SCIENCE 220 1-2 31 45 scie scopus 000184760600004 2-s2.0-0042167594 Engineering, Chemical Polymer Science Engineering Polymer Science Article POLYMER ELECTROLYTE MEMBRANE PROTON CONDUCTIVITY NAFION(R) 117 CROSSOVER POLYELECTROLYTES PERFORMANCE TRANSPORT methanol permeability proton conductivity water cluster sulfonated polyimide DMFC