Characteristics of PVdF copolymer/Nafion blend membrane for direct methanol fuel cell (DMFC)

For direct methanol fuel cell, blends of vinylidene fluoride-hexafluoropropylene copolymer (P(VdF-co-HFP)) and Nation were prepared the different equivalent weight of Nafion. The investigations of the blend morphology were performed by means of permeability test, uptake measurement, differential-scanning calorimetry (DSC), and scanning electron microscopy. In the blend membranes, many pores were created as the content of Nation in blend increased. Then, the methanol uptake was sharply increased. But the methanol permeability was not sharply increased because the methanol permeation through blend membranes is diffusion-controlled process. The methanol permeability of N10 (low equivalent weight) series was similar to that of N11 series (high equivalent weight). The proton conductivity of N10 series was around one and a half times higher than that of N11 series. The cell performance of the blend was much enhanced when the equivalent weight of Nation was 1000. (C) 2004 Elsevier Ltd. All rights reserved.