Nafion/SiO_2复合膜水吸附动力学研究

Water sorption dynamics of Nafion/SiO_2 composite membrane

通过测量Nafion/SiO2复合膜在吸水过程中电阻的变化,对复合膜中水的吸附过程进行了表征,测量了不同温度下Nafion与Nafion/SiO2复合膜中水的吸附曲线,并拟合得到了膜中水的吸附动力学参数。结果显示SiO2的亲水性使得相同条件下复合膜的吸水速率高于Nafion膜。同时分析认为在复合膜中SiO2可能形成了网络结构,起到了支撑骨架的作用,减小了复合膜在吸水过程中的形变,使得复合膜在吸水过程中以第一吸附阶段为主;SiO2的加入同时加速了复合膜中水在界面上的传递过程。

Water sorption process of Nafion/SiO2 composite membrane was characterized through measuring the resistance variation of the composite membrane during water sorption process. The water sorption curves of Nation and Nafion/SiO2 composite membrane under different temperatures were measured, and the water sorption dynamic parameters of membrane were fitted. The results show that the water sorption rate of Nafion/SiO2 composite membrane is larger than that of Nation under the same condition because of the hydrophilicity of SiO2; SiO2 in the composite membrane may form network structure functioning as the supporting skeleton, which reduces the structure change of the membrane during the water sorption process and results in the water sorption process of the composite membrane mainly controlled by the first sorption stage; the addition of SiO2 accelerates the water transport at the gas/membrane interface in the membrane.