2009 Fiscal Year Final Research Report
Clarification of Proton Conduction Processes in Radical-doped Perfluorosulfonic Acid Ion Exchange Membranes Using Elastic Recoil Detection Technique
| Project/Area Number |
19760483
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tohoku University |
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Principal Investigator |
TSUCHIYA Bun Tohoku University, 金属材料研究所, 助教 (90302215)
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| Project Period (FY) |
2007 – 2009
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| Keywords | 高分子電解質 / ラジカル / プロトン伝導度 / 水素輸送 / 反跳粒子検出法 |
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| Research Abstract |
New protonic conduction processes of perfluorosulfonic acid membranes by gamma-ray irradiation at a dose of up to approximately 50 kGy at room temperature in air have been found by direct current resistance and alternative current impedance measurements. The conductivities of the membranes at 300 K in air were enhanced to approximately three orders of magnitude higher than the conductivities of an unirradiated membrane. The hydrogen content in the near-surface region of the irradiated polymers was observed to increase to twice that of the unirradiated polymer by using the elastic recoil detection (ERD) technique. In addition, it was found by the water contact angle measurements that the water absorption characteristics were enhanced due to the production of hydrophilic radicals.By means of ultraviolet, visible, and infrared optical absorption and by hydrogen-ion-exchange capacity measurements, it was revealed that radiation-induced defects such as fluorocarbon and peroxy radicals, and C=O bonds included in carbonyl groups were related to the new proton conduction processes. The modification of hydrogen absorption characteristics due to the radiation-induced defects in near-surface regions leads to the enhancement of the proton conductivity.
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