作者: ASUMAN C KUCUK , JUN MATSUI , TAKUJI MIYASHITA
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摘要: Phosphonic-acid-containing double-decker-shaped polyhedral silsesquioxanes (2-PHOS-DDSQ and PHOS-DDSQ) were synthesized and the proton conductivity of the PHOS-DDSQ cast film was studied under humid and non-humid conditions. Two-armed and four-armed DDSQ functionalized with di (ethylene glycol)(DEG)(2DEG-DDSQ, 4DEG-DDSQ) were used as initial materials. Esterification reaction of phosphate was carried out using POCl3 through the hydroxylterminated groups attached to 2DEG-DDSQ, 4DEG-DDSQ to synthesize 2PHOS-DDSQ and PHOSDDSQ. However, it has been found that 2PHOS-DDSQ is not sustainable against to the water, thus proton conductivity measurements carried out with PHOS-DDSQ. A uniform film of PHOS-DDSQ was fabricated by drop casting. The cast film showed high proton conductivity (0.12 S cm-1) under humid conditions. Moreover, the cast film offered good proton conductivity under non-humid conditions (3.6 10-4 S cm-1 at 170 o C). The conductivity and thermal stability indicate that PHOSDDSQ is a good candidate for use as a proton-conductive membrane in hydrated type fuel cells as well as fuel cells operated at intermediate temperatures (100–200 o C) under non-humid conditions.