Membrane prepared by incorporation of crosslinked sulfonated polystyrene in the blend of PVdF-co-HFP/Nafion: A preliminary evaluation for application in DMFC

Abstract

Sodium salt of sulfonated styrene (SS) was polymerized in situ within the polymeric blend of PVdF-co-HFP/Nafion. The electrical efficiency of this cross-linked semi interpenetrating network membranes were evaluated for its potential application as a polymer electrolyte membrane in direct methanol fuel cell (DMFC). The characteristic aromatic peaks obtained in the FT-IR spectra confirmed the successful incorporation of SS within the polymeric blend. X-ray diffraction analyses were conducted to determine the presence of crystalline and amorphous domains within the structure of the blend membrane. Water uptake measurements at room temperature indicate that above a threshold value of 20wt% of incorporated SS (S-20), water uptake of the semi-IPN membranes increases up to 24%, with an IEC value equal to Nafion, i.e. 0.8meqg-1. The maximum current density was recorded to be 120mAcm-2 at 0.2V, with a cell efficiency (power density) of 24mWcm-2 at 60°C. In addition, proton conductivity and methanol permeability test results indicate that the prepared membrane S-20 is comparable to that of Nafion-117 membrane. © 2014 Elsevier Ltd.