Preparation and characterization of polyvinyl alcohol/chitosan blended membrane for alkaline direct methanol fuel cells

A novel polyvinyl alcohol/chitosan, PCS, blended membrane is prepared by direct blend process and solution casting method. In order to reduce the swelling ratio and enhance the chemical and thermal stabilities of the PCS, PCS membrane is crosslinked with glutaraldehyde to get PCS-G membrane. These membranes are characterized by differential scanning calorimetry, X-ray diffraction, thermogravimetry analysis and mechanical properties of tensile strength and elongation at breaking. The structures of these membranes are identified with azocarmine G. The various membranes are immersed in KOH(aq) solution to form polymer electrolyte membranes and then the alkaline uptake and swelling ratio in the thickness (SWL) and plane direction (SWA) in membranes are studied. The ionic conductivity and methanol permeability of the membranes are conducted. It is found that the value of methanol permeability through the membrane is lower than that of Nafion membrane. Compared to data of Nafion and other studies, PCS91-G membranes with higher selectivity suggest their potential applications in DMFC.

► A novel polyvinyl alcohol/chitosan, PCS, blended membrane is prepared.
► PCS membrane is prepared by the direct blend process and solution casting method.
► The ionic conductivity and methanol permeability through membranes are evaluated.
► Methanol permeability through the membrane is lower than that of Nafion membrane.
► PCS91-GA membranes are good candidates for future alkaline DMFC applications.