A modified Vrentas-Duda model for the correlation of the solvent self-diffusion coefficients in polymer solutions

A new expression for the specific hole free volume in the Vrentas-Duda (VD) model was proposed, and a modified VD model was developed for the correlation of the solvent self-diffusion coefficients in polymers solutions. The new model gives better correlation for the finite concentration solvent self-diffusion coefficients than the VD model, which also shows better predictions for the infinite dilution solvent self-diffusion coefficient,, than the latter, The modified VD model takes into account the pressure effects on diffusion coefficients through the pressure dependence of the specific volumes from an existing equation of state, which can be used to predict the pressure dependence of diffusion coefficients with the parameters obtained from atmospheric pressure diffusivity data.