Molecular dynamics simulation of nafion oligomer solvation in equimolar methanol-water mixture

The solvation of Nafion oligomer in equimolar water-methanol solution was studied by means of molecular dynamics simulations. The skeleton in water-methanol system was found to be substantially folded; its geometry was close to that in pure water. Pronounced flexibility of the skeleton was observed. At the same time, the side chains turned out to be very stiff. No conformation transitions in the side chains were monitored. The skeleton was mostly solvated by methanol. A minor preference for water in the vicinity of the sulfate group was observed. The lifetime of the hydrogen bonds of water and methanol were estimated. The lifetimes for the two components were very close to each other and several times longer than rotational correlation times of individual solute molecules in the bulk.