Surface fluorinated poly(vinyl alcohol)/poly(styrene sulfonic acid-co-maleic acid) membrane for polymer electrolyte membrane fuel cells

Surface fluorination effectively reduced the water absorption of crosslinked polyvinyl alcohol (PVA)/poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA) membranes. The crosslinked PVA membranes were prepared using PSSA_MA as a crosslinking agent as well as a donor of the hydrophilic group (–SO3H and/or –COOH). Surface treatment by gaseous fluorine treatment disrupted the C–OH bonds and generated C–F and C–F2 groups at the membrane surface where atomic percent of fluorine increased up to 5.4%. The membranes with highly hydrophobic fluorinated surface exhibited improved proton conductivity and methanol permeability at a relatively low water uptake.