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-F-2 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. (c) 2009 Elsevier B.V. All rights reserved.