DNA, comprising phosphate ions along a rod-like polymer of heteroatomic rings, was used as the proton transport channel in polymer electrolyte membranes under conditions of high temperature and low humidity. Cast DNA/poly(ethylene oxide) (PEO) blend membranes containing different amounts of DNA were prepared and characterized. Two different molecular weights of PEO were used to provide mechanical strength. The proton conductivity of DNA/PEO membranes increased with the DNA loading and the temperature. The crystallinity of PEO decreased with increasing amounts of DNA, which would improve interaction between the basic oxygen of PEO and the acidic hydrogen of DNA. This would enhance the dissociation of hydrogen from DNA phosphate groups, resulting in increased proton conductivity. The DNA/PEO complexes were investigated in terms of their complexation energy using density functional theory and the effect of hydrogen dissociation from phosphate was studied. (C) 2008 Elsevier B.V. All rights reserved.