摘要
研究了磷钨酸( PWA)掺杂聚乙烯醇(PVA)/纳米二氧化硅(nano SiO2)复合质子导电材料的甲醇渗透性能和质子导电性能。研究结果表明,有机无机纳米复合膜的甲醇阻隔性能随着SiO2 的加入而提高,随着PWA的加入而降低,复合膜和PVA的甲醇渗透率随甲醇浓度的增大而降低。随着温度的升高复合膜的质子导电率也相应增加,复合膜的常温质子导电率可达10-5S·cm-1。质子导电率与温度的关系不符合Arrhenius关系,可用WLF方程或VTF方程来拟合,这种复合膜的质子输送过程主要与聚合物链运动有关。纳米SiO2 的加入有利于提高复合膜在较高温度时的水保留能力,70℃时复合膜的吸水率是纯PVA吸水率的4 倍,使得复合膜可以在较高温度下使用。
Phosphotungstic acid (PWA) doped poly(vinyl alcohol) (PVA)/nano-(silicon dioxide) membrane was prepared. The methanol permeation and proton conductivity of nanocomposite membranes were investigated. The methanol permeability of both PVA and nanocomposite membranes were reduced with increasing concentration of methanol. The methanol barrier ability of the composite membranes was improved with the addition of nano-SiO2. The methanol permeability of PWA doped PVA/SiO2 membrane was lower than pure PVA and a little higher than that of PVA/nano-SiO2 membrane. Proton conductivity of the composite membrane increases with increasing temperature. The composite can exhibit a conductivity as high as 10-5 S·cm-1 at room temperature. Temperature dependence of proton conductivity of the composite can be fitted by WLF or VTF equation rather than Arrhenius equation. Proton transport in the composite membrane was mainly contributed by segmental motion of the polymer. The water retention of the membrane at higher temperature can be improved by the addition of nano-(silicon dioxide). The water absorption of the composite membrane can be four times of that of pure PVA.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2005年第4期563-565,568,共4页
Journal of Functional Materials
基金
教育部留学回国人员科研启动基金
国家自然科学基金资助项目(50103009)
关键词
有机-无机纳米复合
聚乙烯醇
甲醇渗透率
质子电导率
保水能力
Fuel cells
Mechanical permeability
Methanol
Nanostructured materials
Polyvinyl alcohols
Protons
Silica
