NONEQUILIBRIUM MOLECULAR-DYNAMICS SIMULATION OF OXYGEN DIFFUSION THROUGH HEXADECANE MONOLAYERS WITH VARYING CONCENTRATIONS OF CHOLESTEROL

The effect of varying concentrations of cholesterol on the static properties of a hexadecane monolayer and on the diffusion rate of oxygen across the monolayer has been studied by using a novel application of nonequilibrium molecular dynamics. The results show an increased ordering of the hexadecane chains in the region of the monolayer near the added cholesterol with a general increase in monolayer thickness with increasing concentration of cholesterol. The calculation of the diffusion coefficients from the work required to pull oxygen through the monolayer by using a forcing potential suggests an enhanced diffusion rate of oxygen with added cholesterol and a decrease in the diffusion coefficient at higher cholesterol concentrations.